Book 4 Sources

1 How can paints be different colors?

https://www.explainthatstuff.com/howpaintworks.html

https://www.thespruce.com/how-paint-is-made-4587730

https://www.andersonpaintingnc.com/blog/why-your-paint-color-looks-different-than-you-expect

https://sites.google.com/site/scienceofcolour/how-colors-mix

https://burnaway.org/magazine/a-history-of-paint-part-one/

http://www.webexhibits.org/causesofcolor/7A.html

https://en.wikipedia.org/wiki/Paint

https://www.jacksonsart.com/blog/2021/10/15/pigment-colour-index-blue-pigments/

https://www.domain.com.au/living/150000-shades-of-white-why-are-there-so-many-white-paints-to-choose-from-1018556/

2: What is a scramjet?

https://en.wikipedia.org/wiki/Scramjet

https://en.wikipedia.org/wiki/Ramjet

https://www.nasa.gov/centers/langley/news/factsheets/X43A_2006_5.html

https://www.grc.nasa.gov/www/k-12/UEET/StudentSite/engines.html

https://www.blazingtrails.info/post/anatomy-of-a-jet-engine-the-compressor-section

https://www.sciencefocus.com/future-technology/whats-the-difference-between-a-scramjet-and-a-ramjet-engine/

https://skybrary.aero/articles/ramjet

https://www.scienceabc.com/innovation/what-is-a-scramjet-engine.html

https://abcnews.go.com/Technology/story?id=98824&page=1

3: What is & called and why?

https://www.thesaurus.com/e/grammar/ampersand/

https://en.wikipedia.org/wiki/Ampersand

https://en.wikipedia.org/wiki/Apple_Pie_ABC

https://web.archive.org/web/20080508140613/http://www.word-detective.com/052003.html

https://www.dictionary.com/e/ampersand/

https://www.thoughtco.com/what-is-ampersand-symbol-1689083

https://raindance.org/what-an-ampersand-means-in-screenwriting-credits/

https://medium.com/@jonhudson.main/the-old-27th-letter-of-the-english-alphabet-d073c777db26

https://en.wikipedia.org/wiki/Rebracketing

https://history.stackexchange.com/questions/53546/when-did-stop-being-taught-alongside-the-alphabet

4 Can the Mona Lisa ever be sold?

https://www.quora.com/Why-did-Napoleon-hang-the-Mona-Lisa-painting-in-his-bedroom

https://en.wikipedia.org/wiki/Napoleon

https://www.thecollector.com/how-mona-lisa-and-famous-artworks-were-never-finished/

https://en.wikipedia.org/wiki/Leonardo_da_Vinci

https://news.artnet.com/opinion/mona-lisa-sale-1869297

https://en.wikipedia.org/wiki/Mona_Lisa

https://www.thecoldwire.com/who-owns-the-mona-lisa/

https://www.britannica.com/topic/Mona-Lisa-painting

5 How quickly are the continents moving apart?

https://en.wikipedia.org/wiki/Seafloor_spreading

https://en.wikipedia.org/wiki/Mid-ocean_ridge

https://news.curtin.edu.au/media-releases/pacific-ocean-set-to-make-way-for-worlds-next-supercontinent/

https://en.wikipedia.org/wiki/Supercontinent

https://www.amnh.org/explore/ology/earth/power-of-plate-tectonics/mountains

https://www.scientificamerican.com/article/what-do-we-know-about-the/

https://education.nationalgeographic.org/resource/continental-drift

https://oceanservice.noaa.gov/facts/tectonics.html

https://www.earthquakeauthority.com/Blog/2020/Understanding-Plate-Tectonic-Theory

https://www.wtamu.edu/~cbaird/sq/2013/07/18/what-keeps-the-continents-floating-on-a-sea-of-molten-rock/

6: Why is glass transparent?

https://www.azom.com/article.aspx?ArticleID=8141

https://www.scientificamerican.com/article/what-determines-whether-a/

https://science.howstuffworks.com/question404.htm

https://physics.stackexchange.com/questions/7437/why-is-glass-transparent

https://www.corning.com/worldwide/en/innovation/materials-science/glass/how-glass-made.html

https://www.explainthatstuff.com/glass.html

https://andor.oxinst.com/learning/view/article/what-is-light

https://andor.oxinst.com/learning/view/article/absorption-of-light

7: When did we start using tarmac (asphalt) on roads?

https://en.wikipedia.org/wiki/Tarmacadam

https://www.fhwa.dot.gov/infrastructure/back0506.cfm

https://en.wikipedia.org/wiki/Macadam

https://www.bbc.co.uk/nottingham/content/articles/2009/07/03/edgar_hooley_tarmac_feature.shtml

https://www.uksurfacings.com/news/tarmac-invented/

https://en.wikipedia.org/wiki/Road

https://en.wikipedia.org/wiki/Roman_roads

https://www.roadandtrack.com/car-culture/a4447/the-road-ahead-road-evolution/

http://www.laoistarmacadam.ie/asphalt-tarmacadam.html

8: How do LED lights produce different colors?

https://www.rohm.com/electronics-basics/leds/what-are-leds

https://byjus.com/physics/light-emitting-diode/

https://en.wikipedia.org/wiki/Light-emitting_diode

https://en.wikipedia.org/wiki/Electron_hole

https://electronics.howstuffworks.com/led.htm

https://www.lampsplus.com/ideas-and-advice/how-an-led-light-bulb-works/

https://www.colorkinetics.com/global/learn/what-is-an-led

https://www.lampsplus.com/ideas-and-advice/how-an-incandescent-light-bulb-works/

https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/led/color.asp

9: What is chewing gum made of and what happens if you swallow it?

https://www.healthline.com/health/how-long-does-gum-take-to-digest#How-gum-is-digested-in-the-body-

https://www.smithsonianmag.com/arts-culture/a-brief-history-of-chewing-gum-61020195/

https://www.history.com/news/chew-on-this-the-history-of-gum

https://en.wikipedia.org/wiki/Chewing_gum

https://www.wearenopla.com/blogs/news/3-in-4-people-are-unaware-there-is-plastic-in-chewing-gum-did-you-know

https://www.mrsilicone.co.in/2021/01/23/what-is-chewing-gum-made-of/

10: Why do mosquito bites itch?

https://www.yourgenome.org/facts/how-is-malaria-treated-and-prevented/

https://en.wikipedia.org/wiki/Malaria

https://www.tepapa.govt.nz/discover-collections/read-watch-play/science/mosquito-facts/why-cant-we-just-eradicate-mosquitoes

https://www.orkin.com/pests/mosquitoes/mosquito-habitats

https://en.wikipedia.org/wiki/Mosquito

https://www.medicalnewstoday.com/articles/320979

https://www.goodrx.com/conditions/itching/why-mosquito-bites-itch-how-to-stop

https://www.healthline.com/health/why-mosquito-bites-itch#_noHeaderPrefixedContent

https://a-z-animals.com/blog/how-many-mosquitoes-are-in-the-world/

11: How does body armor work?

https://www.sciencedirect.com/topics/engineering/body-armour

https://science.howstuffworks.com/body-armor.htm

https://www.spartanarmorsystems.com/blog/how-body-armor-works-a-technical-look/

https://en.wikipedia.org/wiki/Body_armor

https://en.wikipedia.org/wiki/Bulletproof_vest

https://www.wonderopolis.org/wonder/how-fast-can-a-bullet-travel

https://www.futurity.org/body-armor-boron-carbide-2262412-2/

https://spectrumnews1.com/ca/la-west/news/2020/03/10/how-does-a-bullet-proof-vest-work-

12: What is the smallest thing an electron microscope can see?

http://scienceline.ucsb.edu/getkey.php?key=7046

https://en.wikipedia.org/wiki/Electron_microscope

https://en.wikipedia.org/wiki/Scanning_electron_microscope

https://www.umassmed.edu/cemf/whatisem/

https://www.sciencelearn.org.nz/resources/497-the-microscopic-scale

https://www.khanacademy.org/science/biology/structure-of-a-cell/introduction-to-cells/a/microscopy

13: How do metal detectors work?

https://en.wikipedia.org/wiki/Metal_detector

https://www.minelab.com/knowledge-base/getting-started/how-metal-detectors-work

https://www.explainthatstuff.com/metaldetectors.html

https://electronics.howstuffworks.com/gadgets/other-gadgets/metal-detector.htm

https://www.thoughtco.com/table-of-electrical-resistivity-conductivity-608499

14: Why are sunsets such beautiful colors?

https://scied.ucar.edu/learning-zone/air-quality/how-weather-affects-air-quality

https://spaceplace.nasa.gov/blue-sky/en/

https://www.rmg.co.uk/stories/topics/why-sky-blue

https://en.wikipedia.org/wiki/Cone_cell

https://askabiologist.asu.edu/rods-and-cones

https://www.amnh.org/explore/ology/brain/seeing-color

https://en.wikipedia.org/wiki/Sunset

https://www.wrtv.com/weather/all-eyes-on-the-horizon-heres-why-our-sunsets-have-been-so-colorful

https://www.mercurynews.com/2020/01/05/science-of-sunsets-why-are-we-getting-such-gorgeous-skies/

https://www.reconnectwithnature.org/news-events/the-buzz/the-science-of-sunsets/

15: Why do mustard and wasabi make your nose hurt?

https://justenoughheat.com/education/behind-the-burn/

https://clockworklemon.com/why-does-mustard-burn-your-nose/

https://edu.rsc.org/everyday-chemistry/why-chilli-burns-your-mouth/4014152.article

https://www.labroots.com/trending/videos/11614/why-are-peppers-spicy

https://www.sciencedaily.com/releases/2012/08/120830141335.htm

https://en.wikipedia.org/wiki/Capsaicin

https://www.futurity.org/caterpillars-mustard-evolution-947422/

https://eugene.wbu.com/birds-and-hot-pepper

16: How does LiDAR help archaeologists?

https://en.wikipedia.org/wiki/Lidar

https://www.synopsys.com/glossary/what-is-lidar.html

https://flyguys.com/lidar-technology-helps-archaeology-industry/

https://www.nationalgeographic.com/culture/article/lasers-lidar-driving-revolution-archaeology

https://cosmosmagazine.com/technology/lidar-how-self-driving-cars-see/

https://www.wevolver.com/article/lidar-vs-radar-detection-tracking-and-imaging

17: Why are there many different types of screw head?

https://en.wikipedia.org/wiki/Screw

https://www.theautopian.com/a-suspension-engineer-breaks-down-the-physics-behind-how-a-bolt-works-how-torque-specs-are-determined-how-much-of-your-ratcheting-agony-goes-into-fighting-friction/

https://www.wagnermeters.com/moisture-meters/wood-info/history-of-woodworking/

https://www.fordfasteners.com/a-brief-history-of-fasteners/

https://lemonbin.com/types-of-screw-heads/

https://www.nbk1560.com/en/resources/specialscrew/article/nedzicom-topics-08-come-out/?SelectedLanguage=en

https://hausoftools.com/blogs/news/who-invented-the-screw-and-how-has-the-screw-evolved

https://diy.stackexchange.com/questions/2701/why-are-there-so-many-different-types-of-screws-phillps-flat-hex-star-etc

https://www.hitchcockandking.co.uk/h-k-news/what-are-the-different-types-of-screw/

18: Why do we get jet lag?

https://www.worldtimeserver.com/learn/time-zone-facts-how-big-is-a-time-zone/

https://airandspace.si.edu/explore/stories/evolution-commercial-flying-experience

https://en.wikipedia.org/wiki/Jet_lag

https://www.nhs.uk/conditions/jet-lag/

https://www.mayoclinic.org/diseases-conditions/jet-lag/symptoms-causes/syc-20374027

https://slate.com/human-interest/2015/11/when-did-people-start-moving-fast-enough-to-experience-jet-lag.html

19: Why does drinking milk help after eating spicy food?

https://www.psychologytoday.com/us/blog/brain-babble/201702/why-does-drinking-milk-ease-the-pain-eating-spicy-food

https://www.houstonmethodist.org/blog/articles/2020/sep/how-to-cool-your-mouth-down-after-eating-spicy-food/

https://www.usdairy.com/news-articles/does-milk-help-with-spicy-food

https://health.clevelandclinic.org/does-milk-help-with-spicy-food/

https://www.naturespath.com/en-us/blog/all-about-the-scoville-scale/

https://en.wikipedia.org/wiki/Scoville_scale

https://en.wikipedia.org/wiki/Wilbur_Scoville

https://en.wikipedia.org/wiki/High-performance_liquid_chromatography

20: Why are rabbit ears so long?

https://www.discoverwildlife.com/animal-facts/mammals/why-do-rabbits-have-such-long-ears/

https://bunnylady.com/rabbit-ears/

https://www.rabbitcaretips.com/how-well-can-rabbits-hear/

http://www.pef.uni-lj.si/eprolab/comlab/sttop/sttop-is/TG/Life_science/Elephants.htm

https://en.wikipedia.org/wiki/Rabbit

https://en.wikipedia.org/wiki/Domestic_rabbit

21: How does caffeine stop you from feeling sleepy?

https://www.livescience.com/5269-study-sleepy.html

https://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2014-2015/the-science-of-sleep.html

https://www.sleepscore.com/blog/learn-about-adenosine/

https://www.cspinet.org/caffeine-chart

https://www.ncbi.nlm.nih.gov/books/NBK223808/

https://en.wikipedia.org/wiki/Melatonin

https://byjus.com/question-answer/how-is-glucose-converted-to-atp/

https://en.wikipedia.org/wiki/Glycolysis

22: How long does a 747’s runway need to be?

https://simpleflying.com/boeing-747-shortest-runway-landing/

https://travelonthefly.com/minimum-runway-length-boeing-747/

https://www.slideshare.net/GaurangK/basic-runway-length

https://aertecsolutions.com/en/2019/02/11/the-length-of-a-runway/

https://www.aviationfile.com/factors-effecting-runway-lenght/

https://samchui.com/2022/01/15/top-10-most-produced-commercial-aircraft-types/#.Y2RP5HZBzcs

https://en.wikipedia.org/wiki/Boeing_747

https://modernairliners.com/boeing-747-8/boeing-747-8i-and-8f-specs/

https://aviation.stackexchange.com/questions/33430/why-are-most-runways-made-of-asphalt-and-not-concrete

23: Can you cure male-pattern baldness?

https://www.getmosh.com.au/hair-loss-treatment

https://www.science.org/doi/10.1126/sciadv.1500973

https://www.belgraviacentre.com/blog/what-is-dht

https://www.belgraviacentre.com/blog/study-explores-relevance-of-jak-stat-pathway-to-genetic-hair-loss

https://www.webmd.com/skin-problems-and-treatments/picture-of-the-hair

https://en.wikipedia.org/wiki/Pattern_hair_loss

https://www.aestheticsmd.com/hair-loss/science/science-of-male-pattern-baldness/

https://www.healthline.com/health/male-pattern-baldness

24: When did people first start using locks and keys?

https://www.precision-locksmiths.co.uk/a-history-of-locks/

http://www.historyofkeys.com/locks-history/history-of-locks/

https://medium.com/keycafe/the-history-of-keys-and-locks-8869bdc0ee7f

https://www.ancient-origins.net/history-ancient-traditions/locks-and-keys-0015361

https://en.wikipedia.org/wiki/Pin_tumbler_lock

https://en.wikipedia.org/wiki/Lever_tumbler_lock

http://www.todayifoundout.com/index.php/2014/06/great-lock-controversy-1851/

https://en.wikipedia.org/wiki/Chubb_detector_lock

https://en.wikipedia.org/wiki/Lock_and_key

25: Why do we get a headache when we are dehydrated?

https://www.bbc.com/future/article/20201016-why-we-cant-survive-without-water

https://my.clevelandclinic.org/health/diseases/21517-dehydration-headache

https://coastaluc.com/health-blog/drink-up-this-summer-a-quick-guide-to-the-stages-of-dehydration/

https://www.sciencealert.com/here-s-what-happens-to-your-body-when-you-re-dehydrated

https://www.usgs.gov/special-topics/water-science-school/science/water-you-water-and-human-body

https://www.popsci.com/dehydration-death-thirst-water/

https://www.cdc.gov/healthywater/pdf/global/programs/globaldiarrhea508c.pdf

26: What exactly is cubism?

https://useum.org/Cubism/What-is-Cubism

https://en.wikipedia.org/wiki/Cubism

https://www.studiobinder.com/blog/what-is-positive-and-negative-space-in-art/

https://en.wikipedia.org/wiki/Proto-Cubism

https://www.tate.org.uk/art/art-terms/cubism

https://www.ideelart.com/magazine/what-is-cubism-art

https://www.moma.org/collection/works/82049

27: What is the tallest a mountain can be?

https://www.reddit.com/r/askscience/comments/57g0md/what_is_the_highest_a_mountain_can_be_is_there_a/

https://lowell.edu/olympus-mons-the-biggest-hotspot-in-the-solar-system/

https://www.livescience.com/how-tall-can-mountains-get.html

https://www.forbes.com/sites/trevornace/2015/11/25/tallest-mountain-in-the-world-debatable/?sh=551e9c18221c

https://mounteverest.info/mount-everest-weigh-mass-volume/

https://www.youtube.com/watch?v=i85CHs9UgrU

https://en.wikipedia.org/wiki/Mauna_Kea

https://www.ck12.org/earth-science/weathering-and-erosion/rwa/why-isnt-olympus-mons-on-earth/

28: When was corrugated cardboard first used?

https://www.wired.com/2014/09/curvature-and-strength-empzeal/

https://www.packsize.com/blog/corrugated/where-does-corrugated-cardboard-get-its-strength/

https://en.wikipedia.org/wiki/Corrugated_fiberboard

https://www.supplychain247.com/article/history_of_cardboard_boxes_when_were_cardboard_boxes_invented/premier_handling_solutions

https://www.dssmith.com/tecnicarton/about/newsroom/2018/11/the-origin-of-corrugated-cardboard

http://www.kirkhambox.co.uk/History.html

https://www.jkmoving.com/blog/residential-moving/how-much-weight-can-a-cardboard-box-hold-for-moving

https://boingboing.net/2014/09/06/deep-math-of-the-folded-pizza.html

29: How does the heating element in a toaster work?

https://www.hagley.org/librarynews/history-making-toast

https://www.johndesmond.com/blog/products/the-history-of-toasters/

https://en.wikipedia.org/wiki/Heating_element

https://en.wikipedia.org/wiki/Nichrome

https://cookingindoor.com/toaster/how-hot-does-a-toaster-get/

https://www.seriouseats.com/what-is-maillard-reaction-cooking-science

30: Do ants need to sleep?

https://www.popsci.com/blog-network/our-modern-plagues/do-microbes-sleep/

https://www.tepapa.govt.nz/discover-collections/read-watch-play/science/your-bug-questions-answered/do-spiders-sleep

https://www.eurekalert.org/news-releases/731506

https://fireant.tamu.edu/learn/biology/

https://us.whales.org/whales-dolphins/how-do-dolphins-sleep/

https://www.scienceabc.com/nature/do-plants-and-trees-sleep.html

http://news.bbc.co.uk/earth/hi/earth_news/newsid_8100000/8100876.stm

https://medium.com/a-dose-of-curiosity/do-ants-sleep-c9c2fd001d96

31: Who invented the skateboard?

https://en.wikipedia.org/wiki/Surfing

https://en.freshsurf.de/history-of-surfing/

https://errantsurf.com/history-surfing/

https://en.wikipedia.org/wiki/Skateboarding

https://wonderopolis.org/wonder/who-invented-the-skateboard

https://www.surfertoday.com/skateboarding/who-invented-the-skateboard-and-skateboarding

https://en.wikipedia.org/wiki/Roller_Derby_Skateboard

https://nostalgiacentral.com/pop-culture/fads/skateboards/

32: How do scales work?

https://www.adamequipment.com/aeblog/how-do-balances-and-scales-work

https://electronics.howstuffworks.com/gadgets/fitness/digital-scale.htm

https://www.marsden-weighing.co.uk/blog/how-weighing-scales-work

https://www.explainthatstuff.com/weights_and_balances.html

https://en.wikipedia.org/wiki/Steelyard_balance

https://en.wikipedia.org/wiki/Spring_scale

https://en.wikipedia.org/wiki/Microbalance

33: How thick are Saturn’s rings?

https://astronomy.stackexchange.com/questions/21348/why-only-saturn-has-visible-rings

https://en.wikipedia.org/wiki/Rings_of_Saturn

https://solarsystem.nasa.gov/planets/saturn/in-depth/

https://news.mit.edu/2022/saturn-rings-tilt-missing-moon-0915

https://now.northropgrumman.com/saturns-rings-are-disappearing/

https://slate.com/technology/2014/05/saturn-s-rings-to-scale-thinner-than-paper.html

https://www.syfy.com/syfy-wire/just-how-thin-are-saturns-rings

https://physics.stackexchange.com/questions/6545/why-are-saturns-rings-so-thin

34: Why is the Dead Sea so salty?

https://oceanservice.noaa.gov/facts/whysalty.html

https://en.wikipedia.org/wiki/Dead_Sea

https://manoa.hawaii.edu/exploringourfluidearth/physical/density-effects/measuring-salinity/weird-science-salty-lakes

https://www.livescience.com/56047-why-is-dead-sea-so-salty.html

35: How do sparklers work?

https://en.wikipedia.org/wiki/Sparkler

https://www.mcgill.ca/oss/article/technology-you-asked-general-science/how-do-sparklers-work

https://www.wired.com/2014/07/the-awesome-physics-in-a-simple-sparkler/

https://www.thoughtco.com/how-do-sparklers-work-607351

https://weddingdaysparklers.com/metal-wire-sparklers-vs-wooden-handle-sparklers/

https://physics.stackexchange.com/questions/252411/why-do-some-elements-burn-different-colors

https://en.wikipedia.org/wiki/Spark_(fire)

https://topsmalibu.com/blogs/news/how-are-sparklers-made-the-exciting-science-and-history-of-sparklers

36: Why don’t cats knock things over?

https://faqcats.com/do-cats-have-whiskers-on-their-legs/

https://vcahospitals.com/know-your-pet/why-do-cats-have-whiskers

https://pets.webmd.com/cats/features/why-cats-whiskers

https://www.hillspet.com/cat-care/behavior-appearance/why-do-cats-have-whiskers

https://www.treehugger.com/things-you-didnt-know-about-cat-whiskers-4864051

https://www.floppycats.com/why-do-cats-have-leg-whiskers.html

https://delavanlakesvet.com/news/why-do-cats-have-whiskers

https://en.wikipedia.org/wiki/Whiskers

37: How do fish breathe underwater?

https://www.bbc.co.uk/bitesize/guides/zsry39q/revision/2

https://www.khanacademy.org/science/ap-biology/cellular-energetics/cellular-respiration-ap/a/fermentation-and-anaerobic-respiration

https://byjus.com/biology/aerobic-anaerobic-respiration/

https://rwu.pressbooks.pub/webboceanography/chapter/5-4-dissolved-gases-oxygen/

https://www.chesapeakebay.net/discover/ecosystem/dissolved-oxygen

https://www.goodrx.com/conditions/anesthesia/oxygen-toxicity

https://en.wikipedia.org/wiki/Hypoxia_(medical)

https://nessf.org/how-do-fish-breathe-the-science-behind-gills/

https://science.howstuffworks.com/question386.htm

https://www.livescience.com/how-do-fish-breathe

38: How do throat lozenges work?

https://my.clevelandclinic.org/health/symptoms/21660-inflammation

https://my.clevelandclinic.org/health/diseases/15219-swollen-lymph-nodes

https://www.ncbi.nlm.nih.gov/books/NBK519550/

https://my.clevelandclinic.org/health/body/21871-white-blood-cells

https://en.wikipedia.org/wiki/Pharyngitis

https://vicks.com/en-us/symptom/sore-throat

https://www.londondoctorsclinic.co.uk/blog/throat-lozenges/

39: How does a Geiger counter work?

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/alpha-radiation

https://www.nrc.gov/reading-rm/basic-ref/students/science-101/what-are-different-types-of-radiation.html

https://en.wikipedia.org/wiki/Beta_particle

https://en.wikipedia.org/wiki/Geiger_counter

https://www.livescience.com/how-a-geiger-counter-works.html

https://www.nrc.gov/reading-rm/basic-ref/students/science-101/what-is-a-geiger-counter.html

https://www.co.monmouth.nj.us/documents/118/RADIATION%20HEALTH%20BASICS.pdf

https://en.wikipedia.org/wiki/Electromagnetic_spectrum

https://en.wikipedia.org/wiki/Tokaimura_nuclear_accidents

https://byjus.com/chemistry/cathode-and-anode/

40: Why do fish have scales?

https://wildlifeinformer.com/why-do-fish-have-scales/

https://en.wikipedia.org/wiki/Fish_scale

https://australian.museum/learn/animals/fishes/fish-scales/

https://australian.museum/learn/animals/fishes/cycloid-and-ctenoid-scales/

https://australian.museum/learn/animals/fishes/ganoid-scales/

https://australian.museum/learn/animals/fishes/cosmoid-scales/

https://australian.museum/learn/animals/fishes/placoid-scales/

https://www.letusfindout.com/why-do-fish-have-scales/

https://asknature.org/strategy/why-fish-scales-arent-such-a-drag/

https://en.wikipedia.org/wiki/LZR_Racer

41: Who was Molotov and why was the Molotov cocktail named after him?

https://en.wikipedia.org/wiki/Molotov_cocktail

https://en.wikipedia.org/wiki/Battle_of_Sese%C3%B1a

https://en.wikipedia.org/wiki/Vyacheslav_Molotov

https://www.livescience.com/molotov-cocktails-history

https://www.nationalgeographic.com/history/article/history-of-the-molotov-cocktail

https://physicsforanimators.com/what-is-a-gas-can-it-explode/

https://blogs.loc.gov/law/2018/01/finland-100-years-of-independence-global-legal-collection-highlights/

https://europecentenary.eu/why-did-lenin-recognize-finlands-independence/

42: Why are rubies red, emeralds green, and sapphires blue?

https://en.wikipedia.org/wiki/Ruby

https://www.philophrosyne.com/blogs/jewelry-guide/difference-between-ruby-and-diamond

https://www.americangemsociety.org/ruby-fun-facts/

https://thenaturalrubycompany.com/education/rarity-of-rubies-versus-diamonds/

https://www.thenaturalsapphirecompany.com/t-education_sapphires/

https://www.webexhibits.org/causesofcolor/8.html

https://www.gemrockauctions.com/learn/technical-information-on-gemstones/blue-sapphires-what-makes-sapphires-blue

https://en.wikipedia.org/wiki/Emerald

https://sciencing.com/how-emeralds-formed-5001485.html

https://www.gia.edu/seeing-green

https://www.webexhibits.org/causesofcolor/6AB.html

https://en.wikipedia.org/wiki/Painite

43: How does a laser work?

https://spaceplace.nasa.gov/laser/en/

https://lasers.llnl.gov/education/how-lasers-work

https://science.howstuffworks.com/laser.htm

https://en.wikipedia.org/wiki/Laser

https://en.wikipedia.org/wiki/Carbon-dioxide_laser

https://socratic.org/questions/55dfc97f581e2a2b523c0b49

https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Quantum_Mechanics/09._The_Hydrogen_Atom/Atomic_Theory/Electrons_in_Atoms/Electronic_Orbitals

44: What are the four laws of thermodynamics?

https://hsm.stackexchange.com/questions/11231/why-was-it-necessary-to-define-the-zeroth-law-of-thermodynamics

https://byjus.com/jee/zeroth-law-of-thermodynamics/

https://www.thoughtco.com/zeroth-law-of-thermodynamics-4177952

https://www.grc.nasa.gov/www/k-12/airplane/thermo2.html

https://www.wired.co.uk/article/how-will-universe-end

http://www.csun.edu/~psk17793/G%20Chemistry/entropy.htm

https://thegraduateengineer.com/what-is-the-meaning-of-entropy/

https://www.thoughtco.com/definition-of-entropy-604458

https://en.wikipedia.org/wiki/Laws_of_thermodynamics

https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Thermodynamics/The_Four_Laws_of_Thermodynamics

https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Thermodynamics/The_Four_Laws_of_Thermodynamics/Third_Law_of_Thermodynamics

https://www.livescience.com/50942-third-law-thermodynamics.html

https://www.thoughtco.com/laws-of-thermodynamics-p3-2699420

45: What is in toothpaste?

https://en.wikipedia.org/wiki/Toothpaste

https://www.sciencedirect.com/topics/chemistry/toothpaste

https://www.colgate.com/en-us/oral-health/selecting-dental-products/what-is-in-toothpaste-five-ingredients-and-what-they-do#

https://en.wikipedia.org/wiki/Human_tooth

https://en.wikipedia.org/wiki/Fluoride

https://www.healthline.com/health/what-is-fluoride

https://ec.europa.eu/health/scientific_committees/opinions_layman/fluoridation/en/l-3/2.htm

https://www.humana.com/dental-insurance/dental-resources/tooth-enamel

https://ods.od.nih.gov/factsheets/Fluoride-HealthProfessional/

46: How many revolutions has France had?

https://www.studentsofhistory.com/causes-of-the-french-revolution

https://en.wikipedia.org/wiki/Napoleon

https://www.smithsonianmag.com/history/why-france-its-fifth-republic-180962983/

https://en.wikipedia.org/wiki/July_Revolution

https://en.wikipedia.org/wiki/Charles_X

47: What causes quicksand?

https://en.wikipedia.org/wiki/Quicksand

https://science.howstuffworks.com/environmental/earth/geology/quicksand.htm

https://www.nationalgeographic.com/science/article/quicksand-science-why-it-traps-how-to-escape

https://www.allthingsnature.org/what-is-quicksand.htm

https://wonderopolis.org/wonder/Why-Do-You-Sink-in-Quicksand

https://en.wikipedia.org/wiki/Grain_entrapment

48: Why are there twelve months in a year?

https://mocomi.com/who-decided-a-year-should-have-12-months/

https://www.reddit.com/r/AskHistorians/comments/1iwqu2/why_is_the_year-divided-in-12-awkwardly-arranged/

https://science.howstuffworks.com/science-vs-myth/everyday-myths/time6.htm

https://en.wikipedia.org/wiki/Calendar

https://en.wikipedia.org/wiki/Egyptian_calendar

https://www.qualitylogoproducts.com/blog/history-of-calendars/

https://sites.google.com/site/ishikag610/home/the-calendar-and-the-system-of-irrigation

https://en.wikipedia.org/wiki/Roman_calendar

https://blogs.transparent.com/latin/latin-numbers-1-100/

49: How do mammals keep warm in the winter?

https://animals.mom.com/might-animal-live-cold-places-7738.html

https://www.sciencefocus.com/science/why-does-being-in-cold-water-feel-worse-than-being-in-air-of-the-same-temperature/

https://education.nationalgeographic.org/resource/blubber

https://bestlifeonline.com/how-do-animals-stay-warm/

https://www.mentalfloss.com/article/71087/15-incredible-ways-animals-stay-warm-when-its-chilly

https://asknature.org/strategy/fur-keeps-heat-in-and-cold-water-out/

https://www.scienceworld.ca/stories/do-bears-actually-hibernate/

https://www.naturallynorthidaho.com/2013/01/several-ways-fur-can-keep-animals-war.htm

50: How does an air fryer work?

https://www.masterclass.com/articles/cooking-101-learn-the-science-of-frying-plus-20-recipe-ideas-for-frying-at-home

https://en.wikipedia.org/wiki/Deep_frying

https://en.wikipedia.org/wiki/Air_fryer

https://www.thespruceeats.com/how-does-an-air-fryer-work-4693673

https://www.usnews.com/360-reviews/home-goods/air-fryers/how-does-air-fryer-work

https://www.tasteofhome.com/article/what-is-an-air-fryer/

https://latourangelle.com/pages/what-does-smoke-point-mean

https://cooking.stackexchange.com/questions/86048/does-oil-boil-just-like-water-does

https://www.centrafoods.com/blog/edible-oil-smoke-flash-points-temperature-chart

https://www.doctorkiltz.com/is-vegetable-oil-bad-for-you/

https://www.everydayhealth.com/news/best-worst-oils-health/

51: What is the difference between snowflakes and hail?

https://en.wikipedia.org/wiki/Hail

https://www.abc.net.au/science/articles/2008/09/18/2367819.htm

http://www.differencebetween.net/science/nature/difference-between-snow-and-hail/

https://en.wikipedia.org/wiki/Snow

https://mrcc.purdue.edu/living_wx/hail/index.html

https://scied.ucar.edu/learning-zone/storms/thunderstorms

52: How far will the Voyager probes go?

https://www.reddit.com/r/askscience/comments/kh2y7/will_voyager_1_eventually_crash_into_a_star_or_a/

https://voyager.jpl.nasa.gov/mission/interstellar-mission/

https://voyager.jpl.nasa.gov/

https://www.space.com/predicting-voyager-golden-records-distant-future

https://www.smithsonianmag.com/science-nature/how-far-can-voyager-i-go-4728025/

https://www.nbcnews.com/science/space/artemis-delay-voyager-probes-rcna44188

https://iopscience.iop.org/article/10.3847/2515-5172/ab158e

https://www.syfy.com/syfy-wire/where-will-voyager-pioneer-probes-end-up

53: Why are stealth bombers invisible?

https://www.dailymail.co.uk/news/article-11495107/Americas-B-21-Raider-invisible-weapon-unveiled-today.html

https://www.northropgrumman.com/what-we-do/air/b-2-stealth-bomber/

https://science.howstuffworks.com/stealth-bomber4.htm

https://en.wikipedia.org/wiki/Stealth_aircraft

https://en.wikipedia.org/wiki/Radar

54: Why do our stomachs grumble?

https://www.scientificamerican.com/article/why-does-your-stomach-gro/

https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works

https://en.wikipedia.org/wiki/Stomach_rumble

https://en.wikipedia.org/wiki/Peristalsis

https://wonderopolis.org/wonder/what-makes-your-stomach-growl

https://www.tasteofhome.com/article/why-does-my-stomach-grumble/

55: Why does smoke inhalation kill people?

https://en.wikipedia.org/wiki/Smoke_inhalation

https://www.fireco.uk/the-killing-fumes-why-smoke-is-more-deadly-than-fire/

https://www.webmd.com/lung/smoke_inhalation_treatment_firstaid.htm

https://www.sciencelearn.org.nz/resources/748-what-is-smoke

https://www.qrg.northwestern.edu/projects/vss/docs/propulsion/2-how-do-things-burn.html

https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/carbon-monoxide-poisoning

https://health.ny.gov/environmental/outdoors/air/smoke_from_fire.htm

https://www.cityofandrews.org/fire_marshal/carbon_monoxide.php

https://www.msdmanuals.com/en-jp/home/injuries-and-poisoning/burns/smoke-inhalation

https://www.mayoclinic.org/diseases-conditions/carbon-monoxide/diagnosis-treatment/drc-20370646

56: Why do the leaves on a tree change color in the autumn (fall)?

https://www.discoverwildlife.com/plant-facts/trees/does-tree-sap-freeze/

https://en.wikipedia.org/wiki/Carotenoid

https://www.newscientist.com/article/mg21528791-800-plant-senses-sight/

https://forestryandland.gov.scot/blog/trees-in-autumn

https://www.open.edu/openlearn/science-maths-technology/scales-space-and-time/content-section-2.7

https://spacemath.gsfc.nasa.gov/earth/89Mod11Prob2.pdf

https://askabiologist.asu.edu/questions/why-do-leaves-change-color

https://www.esf.edu/pubprog/brochure/leaves/leaves.htm

57: How does dry cleaning work?

https://en.wikipedia.org/wiki/Dry_cleaning

https://home.howstuffworks.com/home-improvement/household-hints-tips/cleaning-organizing/how-does-dry-cleaning-work.htm

https://www.thespruce.com/what-is-dry-cleaning-2145885

https://www.thespruce.com/why-clothes-shrink-in-the-laundry-2146152

https://www.sglaundry.co.uk/how-does-it-work/is-dry-cleaning-better-than-washing/

https://www.adastradrycleaning.com.au/is-dry-cleaning-better-than-washing/

https://home.howstuffworks.com/how-do-washing-machines-get-clothes-clean2.htm

https://home.howstuffworks.com/laundry-detergent.htm

https://www.drycleanerstogo.com/a-brief-history-of-the-father-of-modern-dry-cleaning-thomas-l-jennings/

58: Does the Oort cloud exist?

https://socratic.org/questions/does-the-oort-cloud-exist-if-so-why-can-t-we-see-it

https://en.wikipedia.org/wiki/Oort_cloud

https://public.nrao.edu/ask/proof-that-the-oort-cloud-exists/

https://solarsystem.nasa.gov/solar-system/oort-cloud/overview/

https://astronomy.stackexchange.com/questions/14256/how-big-do-comets-get

https://www.newscientist.com/article/2080988-the-oort-cloud-surrounds-our-solar-system-why-cant-we-see-it/

http://apps.usd.edu/esci/creation/age/content/creationist_clocks/comets_disintegration.html

https://blogs.nasa.gov/pluto/2018/02/28/the-pis-perspective-why-didnt-voyager-explore-the-kuiper-belt/

59: Why do we have a coccyx?

https://geneticliteracyproject.org/2020/02/12/why-do-humans-have-tailbones/

https://askdruniverse.wsu.edu/2019/10/03/why-do-we-have-a-tailbone/

https://www.businessinsider.com/human-useless-body-parts-2019-1

https://creation.com/tailbone

https://evolution-outreach.biomedcentral.com/articles/10.1186/s12052-014-0012-5

https://www.popsci.com/story/science/human-tailbone-evolution/

https://animals.howstuffworks.com/mammals/bipedalism.htm

60: What makes rain smell?

https://www.theguardian.com/news/2021/sep/11/heaven-scent-science-satisfying-smell-rain-petrichor

https://en.wikipedia.org/wiki/Petrichor

https://www.merriam-webster.com/dictionary/petrichor

https://earthsky.org/earth/what-is-smell-of-rain-petrichor/

https://www.smithsonianmag.com/science-nature/what-makes-rain-smell-so-good-13806085/

https://www.acs.org/content/dam/acsorg/education/students/highschool/chemistryclubs/infographics/petrichor-the-smell-of-rain.pdf

https://www.reconnectwithnature.org/news-events/the-buzz/nature-curiosity-why-does-rain-have-a-smell/

https://www.baranidesign.com/faq-articles/2020/1/19/rain-drop-size-and-speed-of-a-falling-rain-drop

https://www.intechopen.com/chapters/49873

https://www.youtube.com/watch?v=Waqmq_GTyjA

61: Who made the first English dictionary?

https://www.dictionary.com/e/johnson/

https://www.bl.uk/learning/timeline/item102970.html

https://en.wikipedia.org/wiki/Robert_Cawdrey

https://extra.shu.ac.uk/emls/iemls/work/etexts/caw1604w_removed.htm

https://www.bl.uk/collection-items/robert-cawdreys-a-table-alphabeticall

https://en.wikipedia.org/wiki/A_Dictionary_of_the_English_Language

https://www.ruf.rice.edu/~kemmer/Histengl/spelling.html

https://en.wikipedia.org/wiki/List_of_dictionaries_by_number_of_words

https://en.wikipedia.org/wiki/Table_Alphabeticall

https://public.oed.com/blog/the-first-dictionaries-of-english/

62: How does a caterpillar become a butterfly?

https://wisconsinpollinators.com/BU/BA_ButterflyChrysalis.aspx

https://www.sciencedirect.com/topics/chemistry/ecdysone

https://www.abc.net.au/science/articles/2011/12/07/3384014.htm

https://www.sciencedirect.com/topics/neuroscience/caspase

https://en.wikipedia.org/wiki/Caterpillar

https://monarchjointventure.org/monarch-biology/life-cycle/pupa

https://ansp.org/exhibits/online-exhibits/butterflies/lifecycle/

https://monarchjointventure.org/monarch-biology/life-cycle/larva

https://monarchjointventure.org/monarch-biology/life-cycle/egg

https://monarchjointventure.org/faq/how-many-eggs

https://www.cell.com/current-biology/pdf/S0960-9822(10)00291-5.pdf

63: Why are katana blades curved?

https://en.wikipedia.org/wiki/Katana

https://en.wikipedia.org/wiki/Martensite

https://en.wikipedia.org/wiki/Austenite

https://samuraiswords.store/katana-sword/why-is-the-katana-blade-curved/

https://medievalswordsworld.com/why-are-katanas-curved/

https://www.sword-buyers-guide.com/sori.html

https://mas-swords.myshopify.com/blogs/articles/how-japanese-bladesmiths-made-the-katanas-curved-blade?shpxid=73d7a38e-7168-44ad-9cd0-4b059f1ce3a6

https://www.martialartswords.com/blogs/articles/why-some-swords-have-two-edges-instead-of-one

https://en.wikipedia.org/wiki/Scimitar

64: When were pencils invented?

https://blogs.bl.uk/untoldlives/2019/05/the-history-of-the-pencil.html

https://pencils.com/pages/the-history-of-the-pencil

https://en.wikipedia.org/wiki/Pencil

https://en.wikipedia.org/wiki/Graphite

https://www.bl.uk/history-of-writing/articles/a-brief-history-of-writing-materials-and-technologies

https://pensguide.com/how-did-people-write-before-pens-and-pencils/

65: Why is the Gutenberg Bible special?

https://www.history.com/news/printing-press-renaissance

https://aiimpacts.org/historic-trends-in-book-production/

https://en.wikipedia.org/wiki/Wang_Zhen_(inventor)

https://www.history.com/topics/inventions/printing-press

https://www.historytoday.com/reviews/gutenberg%E2%80%99s-bible-real-information-revolution

https://en.wikipedia.org/wiki/Movable_type

https://en.wikipedia.org/wiki/Johannes_Gutenberg

https://en.wikipedia.org/wiki/Gutenberg_Bible

https://www.history.com/news/7-things-you-may-not-know-about-the-gutenberg-bible

66: Why are Quakers the reason we have fixed prices?

https://timespelunking.wordpress.com/2012/11/12/the-invention-of-the-price-tag/

https://en.wikipedia.org/wiki/Price_tag

https://en.wikipedia.org/wiki/Wanamaker%27s

https://www.researchgate.net/post/Who_and_when_first_announced_fixed_one-price_system

https://quaker.org/integrity/

https://skent.ualberta.ca/wp-content/uploads/2020/07/The-Quaker-Ethic-and-the-Fixed-Price-Policy-Max-Weber-and-Beyond.pdf

https://www.systemsofexchange.org/post/the-quakers-and-the-origin-of-fixed-prices

https://aifora.com/en/blog-en/the-history-of-pricing-from-the-barter-system-to-dynamic-pricing/

https://en.wikipedia.org/wiki/Quakers

https://en.wikipedia.org/wiki/George_Fox

https://en.wikipedia.org/wiki/Mitsui_Takatoshi

67: Why can humans throw so fast?

https://pubmed.ncbi.nlm.nih.gov/25283776/

https://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_08.html

https://www.bbc.com/future/article/20140225-human-vs-animal-who-throws-best

https://www.nytimes.com/2013/06/27/science/evolution-on-the-mound-why-humans-throw-so-well.html

https://theconversation.com/how-humans-became-the-best-throwers-on-the-planet-131189

https://scholar.harvard.edu/ntroach/evolution-throwing

68: Why are people left-handed or right-handed?

https://medlineplus.gov/genetics/understanding/traits/handedness/

https://www.livescience.com/what-causes-left-handedness.html

https://en.wikipedia.org/wiki/Handedness

https://www.scienceofpeople.com/why-are-you-right-or-left-handed/

https://www.bbc.com/future/article/20141215-why-are-most-of-us-right-handed

https://www.healthline.com/health/left-brain-vs-right-brain#left-brain-vs-right-brain-myth

69: How does wireless charging work?

https://en.wikipedia.org/wiki/Inductive_charging

https://en.wikipedia.org/wiki/Inductive_coupling

https://www.computerworld.com/article/3235176/wireless-charging-explained-what-is-it-and-how-does-it-work.html

https://case-mate.com/blogs/case-mate-blog/how-does-wireless-charging-work

https://www.nde-ed.org/Physics/Magnetism/electricitymagnet2.xhtml

https://patents.google.com/patent/US527857A/en

https://debugger.medium.com/wireless-charging-is-a-disaster-waiting-to-happen-48afdde70ed9

https://www.computerworld.com/article/3235176/wireless-charging-explained-what-is-it-and-how-does-it-work.html

https://www.digikey.com/en/articles/inductive-versus-resonant-wireless-charging

https://www.freethink.com/hard-tech/wireless-charging

70: Was there really going to be a black Taj Mahal?

https://en.wikipedia.org/wiki/Black_Taj_Mahal

https://en.wikipedia.org/wiki/Shah_Jahan

https://timesofindia.indiatimes.com/travel/destinations/what-if-there-was-a-black-taj-mahal-in-india/articleshow/46383435.cms

https://www.india.com/travel/articles/black-taj-mahal-all-you-need-to-know-about-madhya-pradeshs-kaala-taj-5558243/

https://www.tajmahal.org.uk/legends/black-taj.html

71: What causes thunder?

http://lightningsafety.com/nlsi_info/thunder2.html

https://en.wikipedia.org/wiki/Thunder

https://en.wikipedia.org/wiki/Lightning

https://scijinks.gov/lightning/

https://www.loc.gov/everyday-mysteries/meteorology-climatology/item/what-causes-the-sound-of-thunder/

https://www.sciencefocus.com/planet-earth/where-is-the-safest-place-to-stand-outside-in-a-thunderstorm/

https://www.weather.gov/safety/lightning-odds

72: When did people start having lawns outside their houses?

https://en.wikipedia.org/wiki/History_of_gardening

https://en.wikipedia.org/wiki/Lawn

https://www.gardensillustrated.com/feature/the-history-of-lawns/

https://en.wikipedia.org/wiki/Suburb

73: Why is Christmas on December 25th?

https://www.britannica.com/story/why-is-christmas-in-december

https://www.washingtonpost.com/news/answer-sheet/wp/2015/12/25/why-is-christmas-on-dec-25-a-brief-history-lesson-that-may-surprise-you/

https://www.history.com/news/why-is-christmas-celebrated-on-december-25

https://www.whychristmas.com/customs/25th

https://en.wikipedia.org/wiki/Christmas

https://www.livescience.com/42976-when-was-jesus-born.html

https://en.wikipedia.org/wiki/Date_of_birth_of_Jesus

74: What are contact lenses made of?

https://en.wikipedia.org/wiki/Contact_lens

https://www.thoughtco.com/definition-of-nonpolar-molecule-604582

https://www.thoughtco.com/what-are-contact-lenses-made-of-4117551

https://www.fda.gov/medical-devices/contact-lenses/types-contact-lenses

75: Why is oil measured in barrels?

https://www.goffpetroleum.co.uk/news/why-do-we-measure-oil-in-barrels-and-price-it-in-dollars

https://en.wikipedia.org/wiki/Barrel_(unit)

https://en.wikipedia.org/wiki/Drum_(container)

https://en.wikipedia.org/wiki/Barrel

76: What were the moa and what happened to them?

https://en.wikipedia.org/wiki/Moa

https://www.science.org/content/article/why-did-new-zealands-moas-go-extinct

https://www.museum.ie/en-IE/Collections-Research/Collection/Documentation-Discoveries/Artefact/An-Extinct-Moa-Bird-from-New-Zealand/0ac1baaa-1003-49a0-8a03-b780f06a5366

https://sciencenordic.com/animals-biology-biotechnology/humans-alone-killed-off-the-giant-moa-bird/1398602

https://en.wikipedia.org/wiki/Haast%27s_eagle

https://teara.govt.nz/en/when-was-new-zealand-first-settled

77: What is the densest material in the universe?

https://www.middleschoolchemistry.com/lessonplans/chapter3/lesson1

https://en.wikipedia.org/wiki/Osmium

https://www.science.org/content/article/neutron-stars-billions-times-stronger-steel

https://www.newscientist.com/article/mg20928026-900-eight-extremes-the-densest-thing-in-the-universe/

https://en.wikipedia.org/wiki/Neutron_star

https://letstalkscience.ca/educational-resources/stem-in-context/life-and-death-stars

https://www.thoughtco.com/blue-supergiant-stars-3073592

http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/pulsar.html

78: When were sunglasses invented?

https://venetiancat.blogspot.com/2014/06/venetians-put-on-show-spectacles-fit.html

https://www.allaboutvision.com/sunglasses/faq/invention-of-shades/

https://www.sunglassmuseum.com/blogs/news/a-brief-history-of-sunglasses

https://www.americansunglass.com/blogs/news/ever-want-to-know-how-sunglasses-came-about

https://en.wikipedia.org/wiki/Sunglasses

79: Why do we still have wisdom teeth if we don’t need them?

https://science.howstuffworks.com/life/evolution/no-wisdom-teeth.htm

https://www.newscientist.com/article/dn13615-evolution-myths-everything-is-an-adaptation/

https://www.kenilworthdentalassociates.com/the-evolutionary-reason-for-wisdom-teeth/

https://en.wikipedia.org/wiki/Human_jaw_shrinkage

https://www.biltmoreoralsurgery.com/blog/why-do-we-have-wisdom-teeth-anyway/

https://www.smithsonianmag.com/smart-news/how-dawn-farming-changed-our-mouths-worst-180954167/

https://www.scientificamerican.com/article/mind-your-fs-and-vs-agriculture-may-have-shaped-both-human-jaws-and-language/

https://www.thedentaldistrict.com/wellness/why-do-wisdom-teeth-come-in-so-late/

80: Why do we get goosebumps?

https://www.nih.gov/news-events/nih-research-matters/what-goosebumps-are

https://www.livescience.com/32349-what-causes-goose-bumps.html

https://www.smithsonianmag.com/science-nature/why-did-humans-evolve-lose-fur-180970980/

https://www.discovermagazine.com/planet-earth/why-do-people-get-goosebumps

81: When did people start using glass for windows?

https://www.thenbs.com/knowledge/windows-glass-glazing-a-brief-history

https://www.paarhammer.com.au/blog/history-of-windows

https://en.wikipedia.org/wiki/Window

82: Is an Olympic gold medal really made of gold?

https://en.as.com/en/2021/07/23/olympic_games/1627028063_790955.html

https://www.cosmopolitan.com/entertainment/celebs/a39011500/are-olympic-medals-real-gold/

https://sports.yahoo.com/olympic-medals-real-gold-exactly-212240754.html

https://www.nbcsports.com/northwest/tokyo-olympics/history-olympic-medals-explained-what-know-tokyo

https://supply.co/blogs/journal/when-did-gold-silver-and-bronze-become-the-pinnacle-achievement

https://globalquiz.org/en/question/when-and-where-was-the-idea-of-gold-silver-and/

83: What causes pins and needles?

https://www.nhs.uk/symptoms/pins-and-needles/

https://www.nhs.uk/symptoms/pins-and-needles/

84: Why do we say “born to the purple”? What is Tyrian purple?

https://www.citizenwolf.com/blogs/news/tyrian-purple-the-colour-of-royalty

https://www.bbc.com/culture/article/20180801-tyrian-purple-the-regal-colour-taken-from-mollusc-mucus

https://en.wikipedia.org/wiki/Tyrian_purple

https://sarata.com/bible/verses/about/purple.html

85: How is volcanic ash made and how dangerous is it?

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/volcanic-ash

https://en.wikipedia.org/wiki/Volcanic_ash

https://education.nationalgeographic.org/resource/volcanic-ash

https://edition.cnn.com/travel/article/ash-cloud-aircraft-explainer/index.html

https://en.wikipedia.org/wiki/Pyroclastic_flow

86: Why is there a sunken continent underneath New Zealand?

https://beta.nsf.gov/news/sinking-zealandia-earths-hidden-continent-linked

https://en.wikipedia.org/wiki/Zealandia

https://education.nationalgeographic.org/resource/zealandia

https://www.geosociety.org/gsatoday/archive/27/3/article/GSATG321A.1.htm

https://www.nzherald.co.nz/nz/zealandia-geologist-to-shed-new-light-on-our-lost-continent/PPNLJYYERKEWF7ZW4DKZZGUZRQ/

87: When were glasses invented?

https://en.wikipedia.org/wiki/Far-sightedness

https://en.wikipedia.org/wiki/Myopia

https://en.wikipedia.org/wiki/Glasses

https://www.fostergrant.com/the-history-of-glasses

http://www.glasseshistory.com/

https://nativetrailshome.com/history-of-murano-glass/

https://www.nei.nih.gov/about/news-and-events/news/myopia-close-look-efforts-turn-back-growing-problem

88: Why does hot air rise?

https://www.grc.nasa.gov/www/k-12/Summer_Training/FranktonES/Convection_main_page.html

https://wonderopolis.org/wonder/does-hot-air-always-rise

https://scienceline.ucsb.edu/getkey.php?key=3901

https://teachearthscience.org/Resources/HotAir.pdf

https://theconversation.com/curious-kids-why-does-cold-air-go-down-and-hot-air-go-up-171408

https://www.newscientist.com/article/mg20928026-900-eight-extremes-the-densest-thing-in-the-universe/

89: How does a hydrogen fuel cell work?

https://www.energy.gov/eere/fuelcells/hydrogen-production-electrolysis

https://afdc.energy.gov/fuels/hydrogen_production.html

https://afdc.energy.gov/vehicles/how-do-fuel-cell-electric-cars-work

https://www.energy.gov/eere/fuelcells/fuel-cells

https://www.twi-global.com/technical-knowledge/faqs/what-is-a-hydrogen-fuel-cell#HowDoesAHydrogenFuelCellWork

https://en.wikipedia.org/wiki/Fuel_cell

https://en.wikipedia.org/wiki/Proton-exchange_membrane_fuel_cell

https://driveclean.ca.gov/hydrogen-fuel-cell

https://chemistry.stackexchange.com/questions/7854/why-is-platinum-used-as-a-catalyst-in-fuel-cell-electrodes-and-elsewhere

https://www.japantimes.co.jp/news/2023/01/05/business/corporate-business/toyota-hydrogen-fuel-car/

https://www.energy.gov/eere/fuelcells/liquid-hydrogen-delivery

90: How does LSD work?

https://en.wikipedia.org/wiki/Lysergic_acid_diethylamide

https://en.wikipedia.org/wiki/Glutamate_(neurotransmitter)

https://americanaddictioncenters.org/lsd-abuse/what-does-lsd-do-to-your-brain

https://www.nih.gov/news-events/nih-research-matters/protein-structure-reveals-how-lsd-affects-brain

https://www.newscientist.com/article/2119397-how-lsd-affects-the-brain-and-creates-its-trippy-effect/

https://www.webmd.com/mental-health/what-is-dopamine

https://my.clevelandclinic.org/health/articles/22572-serotonin

https://www.health.harvard.edu/mind-and-mood/dopamine-the-pathway-to-pleasure

https://www.theguardian.com/science/2006/feb/25/drugs.thisweekssciencequestions

https://scholarworks.arcadia.edu/cgi/viewcontent.cgi?article=1013&context=senior_theses

https://healthyliferecovery.com/what-are-the-long-term-effects-of-lsd/

91: Why are carrots orange?

https://books.google.co.jp/books?id=KFQMt1Ww6osC&pg=PA81&redir_esc=y#v=onepage&q&f=false

https://www.economist.com/the-economist-explains/2018/09/26/how-did-carrots-become-orange

https://en.wikipedia.org/wiki/Carotenoid

https://en.wikipedia.org/wiki/Carrot

https://www.livescience.com/why-are-carrots-orange.html

https://www.quora.com/Why-do-some-vegetables-for-example-carrots-contain-light-absorbing-pigments-if-they-grow-underground

https://askdruniverse.wsu.edu/2020/04/17/why-are-carrots-orange/

https://pubmed.ncbi.nlm.nih.gov/23876238/

https://tastehistory.mt/carrot-seeds/

https://www.alimentarium.org/en/fact-sheet/carrot

92: What is a solid-state battery?

https://www.samsungsdi.com/column/technology/detail/56462.html?listType=gallery

https://www.energy.gov/eere/articles/how-does-lithium-ion-battery-work

https://en.wikipedia.org/wiki/Solid-state_battery

https://www.carmagazine.co.uk/electric/solid-state-battery-ev/

https://www.science.org.au/curious/technology-future/batteries

https://article.murata.com/en-global/article/basic-lithium-ion-battery-4

https://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery.htm

https://en.wikipedia.org/wiki/Lithium

https://www.eonenergy.com/electric-vehicle-charging/costs-and-benefits/battery-capacity-and-lifespan.html

https://studiousguy.com/solid-state-battery-working-principle-uses-advantages/

93: What is cotton?

https://learn.genetics.utah.edu/content/cotton/what

https://www.frontiersin.org/articles/10.3389/fpls.2012.00104/full

https://www.cottonworks.com/en/topics/sourcing-manufacturing/fiber-science/cotton-fiber-development-maturation/

https://www.cottonmill.com/blog/the-life-cycle-of-the-cotton-plant/

https://www.theworldcounts.com/challenges/consumption/clothing/world-cotton-production-statistics

https://www.cotton.org/pubs/cottoncounts/story/how.cfm

https://en.wikipedia.org/wiki/Cotton

https://www.masterclass.com/articles/what-is-cotton

https://sewport.com/fabrics-directory/cotton-fabric

https://www.the-sustainable-fashion-collective.com/2014/12/12/how-is-cotton-made-why-bad

https://blog.machinefinder.com/19637/picking-cotton-less-time-john-deere-cp690

94: Why doesn’t silicone melt in the oven?

https://www.sciencedirect.com/science/article/pii/S2542504820300245

https://www.simtec-silicone.com/blogs/how-is-silicone-produced/

https://en.wikipedia.org/wiki/Plastic

https://firesafetysupport.com/what-temperature-does-rubber-melt/

https://education.seattlepi.com/hot-water-melt-plastic-3626.html

https://en.wikipedia.org/wiki/Silicone_rubber

https://en.wikipedia.org/wiki/Silicone

https://silicone.co.uk/news/temperatures-can-silicone-rubber-withstand/

https://jehbco.com.au/improving-extreme-temperature-degradation-silicone-rubber-using-flame-retardant-additives/

https://sunwestcontainer.com/blog/why-doesnt-silicone-melt-or-burn-and-questions-about-silicone-rubber-heaters

https://techiescientist.com/does-silicone-melt/

https://www.simtec-silicone.com/blogs/the-history-of-the-silicone-elastomer/

https://en.wikipedia.org/wiki/Silly_Putty

95: When was the first subway built?

https://en.wikipedia.org/wiki/London_Underground

https://en.wikipedia.org/wiki/History_of_the_London_Underground

https://en.wikipedia.org/wiki/Metropolitan_Railway

https://www.bbc.com/news/uk-england-derbyshire-22342239

https://en.wikipedia.org/wiki/London

http://www.demographia.com/dm-lon31.htm

96: How was the Great Pyramid at Giza built?

https://www.brown.edu/academics/archaeology/sites/academics-archaeology/files/publication/document/Rigby2016.pdf

https://www.nationalgeographic.com/history/article/giza-pyramids

https://www.britannica.com/video/226777/did-enslaved-people-build-the-pyramids

https://www.si.edu/spotlight/ancient-egypt/pyramid

https://www.egypttoday.com/Article/4/119442/How-were-the-Great-Pyramids-of-Giza-built

https://www.history.com/news/ancient-egypt-pyramid-ramp-discovery

https://en.wikipedia.org/wiki/Khufu

https://en.wikipedia.org/wiki/Egyptian_pyramid_construction_techniques

https://en.wikipedia.org/wiki/Great_Pyramid_of_Giza

97: How did Galileo realize that the Earth orbits the sun?

https://en.wikipedia.org/wiki/Galileo_Galilei

https://en.wikipedia.org/wiki/Geocentric_model

https://en.wikipedia.org/wiki/Heliocentrism

https://en.wikipedia.org/wiki/Nicolaus_Copernicus

https://astronomy.com/magazine/ask-astro/2017/01/proof-earth-revolves-around-the-sun

https://www.forbes.com/sites/startswithabang/2021/03/10/the-biggest-problem-in-science-isnt-groupthink/?sh=149d4412626c

https://www.wondriumdaily.com/the-heliocentric-theory-nicolaus-copernicus-and-galileo-galilei/

https://phys.org/news/2016-01-heliocentric-universe.html

https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question46.html

https://earthobservatory.nasa.gov/features/OrbitsHistory

https://solarsystem.nasa.gov/news/307/galileos-observations-of-the-moon-jupiter-venus-and-the-sun/

98: How many dimensions are there?

https://www.smithsonianmag.com/smart-news/our-continued-existence-means-other-dimensions-are-probably-super-tiny-180970487/

https://aeon.co/essays/how-many-dimensions-are-there-and-what-do-they-do-to-reality

https://www.mentalfloss.com/article/501926/how-many-dimensions-are-there

https://now.northropgrumman.com/how-many-dimensions-are-there-in-the-universe/

https://phys.org/news/2014-12-universe-dimensions.html

https://en.wikipedia.org/wiki/Dimension

https://cms.cern/physics/do-we-really-live-only-three-dimensions

https://www.space.com/17594-string-theory.html

https://www.quora.com/Why-are-Quantum-Mechanics-and-General-Relativity-incompatible

https://bigthink.com/surprising-science/physicists-outline-10-different-dimensions-and-how-youd-experience-them/

https://www.space.com/why-is-gravity-so-weak

99: What was the first insurance company?

https://en.wikipedia.org/wiki/Hamburger_Feuerkasse

https://www.beyond-history.com/en/english-beyond-history-blog/article/2021/11/30/hamburger-feuerkasse-the-oldest-existing-insurance-company-in-the-world/

https://www.iii.org/publications/insurance-handbook/brief-history

https://en.wikipedia.org/wiki/History_of_insurance

https://en.wikipedia.org/wiki/Life_insurance

https://www.irmi.com/articles/expert-commentary/the-worlds-first-insurance-company

https://www.wsrinsurance.com/how-insurance-began-3000-years-of-history/

https://en.wikipedia.org/wiki/Lloyd%27s_Coffee_House

https://en.wikipedia.org/wiki/Edmond_Halley

100: How does aspirin work?

https://www.nytimes.com/2000/04/18/health/how-aspirin-works-its-magic.html

https://www.yourhormones.info/hormones/prostaglandins/

https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/drug-cabinet/aspirin

https://my.clevelandclinic.org/health/articles/24411-prostaglandins

https://www.banamine.com/research/prostaglandins.asp

https://source.wustl.edu/2007/07/aspirin-the-mighty-drug/

http://edition.cnn.com/2010/HEALTH/12/22/aspirin.history/index.html

https://en.wikipedia.org/wiki/Aspirin

101: Why is hypothermia dangerous?

https://tc.canada.ca/en/marine-transportation/marine-safety/hypothermia-survival-cold-water

https://www.medicalnewstoday.com/articles/182197

https://trustcarehealth.com/blog/hypothermia-explained

https://en.wikipedia.org/wiki/Shivering

https://www.labxchange.org/library/items/lb:LabXchange:ffe2c3ef:html:1

https://en.wikipedia.org/wiki/Warm-blooded

https://en.wikipedia.org/wiki/Hypothermia

https://www.mayoclinic.org/diseases-conditions/hypothermia/symptoms-causes/syc-20352682

https://www.cdc.gov/disasters/winter/staysafe/hypothermia.html

102: How can planes fly upside down?

https://web.fscj.edu/Milczanowski/psc/lect/Ch4/slide2.htm

https://en.wikipedia.org/wiki/Bernoulli%27s_principle

https://www.grc.nasa.gov/www/k-12/UEET/StudentSite/dynamicsofflight.html

https://www.popularmechanics.com/flight/a19875/why-airplane-wings-angle-backwards-explainer/

https://www.cam.ac.uk/research/news/how-wings-really-work

https://www.scienceabc.com/eyeopeners/how-airplane-jets-stunt-planes-fly-upside-down-lift-shape-of-wings-angle-of-attack.html

https://www.wtamu.edu/~cbaird/sq/2012/12/17/how-do-airplanes-fly-upside-down-if-its-the-shape-of-the-wings-that-make-them-fly/

https://www.sciencefocus.com/future-technology/how-are-some-planes-able-to-fly-upside-down/

https://www.smithsonianmag.com/air-space-magazine/how-things-work-flying-upside-down-27746739/

https://www.airlineratings.com/news/can-large-commercial-planes-fly-upside-down/

103: How wild was the Wild West?

https://www.livescience.com/was-the-west-wild.html

https://www.historyextra.com/period/victorian/wild-west-how-lawless-was-american-frontier/

https://en.wikipedia.org/wiki/American_frontier

https://thehistoryjunkie.com/wild-west-timeline/

https://www.amrevmuseum.org/big-idea-5-native-american-soldiers-and-scouts

https://worldpopulationreview.com/state-rankings/wild-west-states

https://www.independent.org/publications/tir/article.asp?id=803

https://www.wsj.com/articles/new-york-city-saw-fewer-murders-in-2022-but-major-crimes-overall-rose-11672954714

104: Why are university degrees called a bachelor’s, a master’s and a doctorate?

https://everything-everywhere.com/the-history-of-academic-degrees/

https://en.wikipedia.org/wiki/Knight_Bachelor

https://uncrcow.tumblr.com/post/177984467810/what-is-the-origin-of-the-academic-degree

http://www.hitechcj.com/criminal-justice-degree-online/degree_explanations.html

https://www.academicapparel.com/caps/History-Academic-Degrees.html

https://www.linkedin.com/pulse/origins-academic-degrees-muhammad-ikhmal/?trk=portfolio_article-card_title

https://en.wikipedia.org/wiki/Academic_degree

https://en.wikipedia.org/wiki/University

https://research.com/universities-colleges/oldest-university-in-the-world

https://www.wikiwand.com/en/University

https://www.etymonline.com/word/bachelor

105: Why do ostriches have two kneecaps?

https://www.scienceinschool.org/article/2011/ostrich/

https://animaldiversity.org/collections/mammal_anatomy/running_fast/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5830293/

https://www.saintlukeskc.org/health-library/kneecap-patella-and-knee-joint

https://yourfunctionalhealth.com/why-do-we-have-knee-caps-anyway/

https://www.discoverwildlife.com/animal-facts/birds/why-do-ostriches-have-two-kneecaps/

https://www.sciencedaily.com/releases/2017/07/170703083313.htm

https://www.newscientist.com/article/2146112-why-the-ostrich-is-the-only-living-animal-with-four-kneecaps/

https://www.earth.com/news/ostriches-double-kneecap/

https://whatsinjohnsfreezer.com/2017/06/08/why-2-kneecaps/

106: Why can’t all animals be domesticated?

https://www.bbc.com/news/science-environment-14616161

https://www.frontiersin.org/articles/10.3389/fevo.2020.00103/full

https://www.amnh.org/exhibitions/horse/domesticating-horses/domestication-timeline

https://www.alleycat.org/resources/the-natural-history-of-the-cat/

https://www.ed.ac.uk/sites/default/files/atoms/files/1._understanding_feline_social_structure.pdf

https://www.nationalgeographic.com/animals/article/domesticated-animals

https://www.forbes.com/sites/quora/2016/10/24/why-can-some-animals-be-domesticated-but-not-others/?sh=32a446d15df4

https://www.livescience.com/33870-domesticated-animals-criteria.html

https://wonderopolis.org/wonder/why-cant-every-animal-be-a-pet

107: What is a Distributed Denial of Service attack?

https://www.paloaltonetworks.com/cyberpedia/what-is-a-denial-of-service-attack-dos

https://www.cloudflare.com/learning/ddos/what-is-a-ddos-attack/

https://www.cisa.gov/uscert/ncas/tips/ST04-015

https://www.cloudflare.com/learning/ddos/glossary/denial-of-service/

https://en.wikipedia.org/wiki/Denial-of-service_attack

https://cloud.google.com/blog/products/identity-security/how-google-cloud-blocked-largest-layer-7-ddos-attack-at-46-million-rps

https://www.cloudflare.com/learning/network-layer/what-is-a-packet/

https://medium.com/@isaac_70614/how-does-a-computer-get-a-web-page-3f5b9458cf05

https://www.reddit.com/r/AskProgramming/comments/io4al6/how_many_concurrent_tcp_connections_can_a_server/

https://www.kaspersky.com/resource-center/threats/botnet-attacks

https://www.kaspersky.com/resource-center/threats/ip-spoofing

108: Does blood volume decrease if a limb is amputated?

https://www.stanfordchildrens.org/en/topic/default?id=what-is-plasma-160-37

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3201099/

https://biologysir.com/how-much-blood-is-in-the-human-body/

https://cvphysiology.com/Blood%20Pressure/BP025

https://www.bloodpressureuk.org/your-blood-pressure/understanding-your-blood-pressure/why-is-high-blood-pressure-a-problem/kidney-disease-and-high-blood-pressure/

https://www.thenakedscientists.com/articles/questions/do-amputees-have-higher-blood-pressure-because-they-have-fewer-blood-vessels

https://www.innerbody.com/anatomy/cardiovascular/arm-hand

https://www.webmd.com/heart/difference-between-arteries-and-veins

https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/circulatory-system

https://www.reddit.com/r/explainlikeimfive/comments/1r5nf9/eli5_if_a_limb_gets_amputated_what_happens_to_the/

https://researchfeatures.com/future-bionic-limbs/

109: What was the Royal African Company?

https://www.npg.org.uk/learning/digital/history/abolition-of-slavery/the-slave-trade

https://en.wikipedia.org/wiki/John_Hawkins_(naval_commander)

https://en.wikipedia.org/wiki/Atlantic_slave_trade

https://en.wikipedia.org/wiki/Triangular_trade

https://www.pbs.org/wgbh/aia/part1/1p269.html

https://schoolshistory.org.uk/topics/british-empire/economic-consequences-of-empire/royal-african-company/

https://en.wikipedia.org/wiki/Royal_African_Company

https://www.history.com/news/what-was-the-royal-african-company

https://www.pepysdiary.com/encyclopedia/7105/

https://www.discoveringbristol.org.uk/slavery/routes/places-involved/britain/british-law/

https://www.slavevoyages.org/voyage/database/

https://www.bl.uk/collection-items/charter-granted-to-the-company-of-royal-adventurers-of-england-relating-to-trade-in-africa-1663

110: How do parrots talk?

https://en.wikipedia.org/wiki/Parrot

https://www.mentalfloss.com/article/73954/why-can-parrots-talk

https://petkeen.com/why-do-parrots-talk/

https://slate.com/technology/2012/11/swearing-parrots-why-do-parrots-mimic-human-speech.html

https://www.audubon.org/news/why-do-parrots-talk

https://www.scientificamerican.com/article/experts-parrots-mimic/

https://www.psittacology.com/how-do-parrots-talk/

https://en.wikipedia.org/wiki/Syrinx_(bird_anatomy)

111: How does a canal lock work?

https://en.wikipedia.org/wiki/Flash_lock

https://www.canaljunction.com/canal_holiday/lock_skills.htm

https://www.whiltonmarina.co.uk/narrowboat-blog/2013/11/narrowboating-guides-canal-locks/

https://science.jrank.org/pages/3986/Lock-History.html

https://citymonitor.ai/transport/so-how-does-canal-boat-travel-uphill-3844

112: Why do some things bounce and other things don’t?

http://scienceline.ucsb.edu/getkey.php?key=4384

https://van.physics.illinois.edu/ask/listing/111

https://howthingsfly.si.edu/ask-an-explainer/what-gravitational-potential-energy

https://www.khanacademy.org/science/physics/work-and-energy/work-and-energy-tutorial/a/what-is-kinetic-energy

https://www.exploratorium.edu/sports/ball_bounces/ballbounces2.html

https://physics.stackexchange.com/questions/398476/why-dont-all-objects-bounce-like-rubber-balls

https://www.scienceabc.com/nature/why-does-a-rubber-ball-bounce-back-while-an-iron-ball-doesnt.html

113: What are the four fundamental forces?

https://www.space.com/why-is-gravity-so-weak

https://www.sciencefocus.com/space/gravity/

https://www.quantamagazine.org/gravitons-revealed-in-the-noise-of-gravitational-waves-20200723/

https://profmattstrassler.com/articles-and-posts/particle-physics-basics/why-do-particles-decay/most-particles-decay-why/

https://physics.stackexchange.com/questions/658605/how-do-the-strong-and-weak-forces-relate-to-nuclear-fission-and-fusion

https://physics.stackexchange.com/questions/148114/how-to-explain-electrons-interaction-via-the-weak-force

https://ecuip.lib.uchicago.edu/multiwavelength-astronomy/astrophysics/06.html

https://energyeducation.ca/encyclopedia/Weak_nuclear_force

https://energyeducation.ca/encyclopedia/Electromagnetic_force

https://ecuip.lib.uchicago.edu/multiwavelength-astronomy/astrophysics/05.html

https://www.space.com/four-fundamental-forces.html

https://en.wikipedia.org/wiki/Fundamental_interaction

114: How do glaciers move?

https://asf.alaska.edu/information/glacier-power/glacier-power-how-do-glaciers-form/

https://asf.alaska.edu/information/glacier-power/glacier-power-how-do-glaciers-move/

https://asf.alaska.edu/information/glacier-power/glacier-power-what-are-crevasses/

https://www.antarcticglaciers.org/glacier-processes/glacier-flow-2/glacier-flow-ii-stress-and-strain/

https://byjus.com/physics/shearing-stress/

https://www.antarcticglaciers.org/glacier-processes/glacier-flow-2/glacier-flow/

https://www.antarcticglaciers.org/glacier-processes/glacier-flow-2/

https://www.antarcticglaciers.org/glacier-processes/mass-balance/glacier-accumulation-and-ablation/

https://nsidc.org/learn/parts-cryosphere/glaciers/science-glaciers

https://www.coolgeography.co.uk/A-level/AQA/Year%2012/Cold%20environs/Ice%20movement/Ice%20movement.htm

https://www.nps.gov/articles/howglaciersmove.htm

115: Why do soldiers break stride on a bridge?

https://www.warhistoryonline.com/war-articles/broughton-suspension-bridge-collapse.html?chrome=1

https://www.wearethemighty.com/military-life/soldiers-marching-over-bridges-myth/

https://www.youtube.com/watch?v=dihQuwrf9yQ

https://en.wikipedia.org/wiki/Resonance

https://science.howstuffworks.com/resonance-info.htm

https://www.livescience.com/34608-break-stride-frequency-of-vibration.html

https://www.pbslearningmedia.org/resource/lsps07.sci.phys.energy.glassbreak/glass-breaking-with-sound/

https://wonderopolis.org/wonder/how-can-a-voice-break-glass

116: Do any other animals cry?

https://www.healthline.com/health/why-do-onions-make-you-cry#why-onions-make-you-cry

https://en.wikipedia.org/wiki/Crocodile_tears

https://www.whyanimalsdothething.com/elephants-dont-cry

https://www.abc.net.au/radionational/programs/archived/bodysphere/features/4837824

https://time.com/4254089/science-crying/

https://www.discovermagazine.com/health/humans-are-the-only-animals-that-cry-and-we-dont-know-why

https://en.wikipedia.org/wiki/Tears

https://www.menshealth.com/health/a19523994/why-we-cry/

117: Why did early humans leave Africa?

https://www.history.com/news/humans-evolution-neanderthals-denisovans

https://humanorigins.si.edu/evidence/human-fossils/species/homo-sapiens

https://www.yourgenome.org/stories/evolution-of-modern-humans/

https://humanorigins.si.edu/education/introduction-human-evolution

https://www.snexplores.org/article/genetics-show-humans-likely-trace-back-to-africa

https://www.discovermagazine.com/planet-earth/why-did-early-humans-leave-africa

https://www.smithsonianmag.com/history/the-great-human-migration-13561/

https://www.sciencedaily.com/releases/2017/10/171004151231.htm

https://en.wikipedia.org/wiki/Evolution_of_human_intelligence

118: When did globalization start?

https://www.history.com/news/silk-road-trade-goods

https://www.investopedia.com/ask/answers/020915/when-did-globalization-start.asp

https://www.weforum.org/agenda/2019/01/how-globalization-4-0-fits-into-the-history-of-globalization/

https://www.etymonline.com/word/globalization

https://cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/g/Globalization.htm

119: What causes a tsunami?

https://oceanservice.noaa.gov/facts/wavesinocean.html

https://www.noaa.gov/education/resource-collections/ocean-coasts/tsunamis

https://www.ngdc.noaa.gov/hazard/tsunami-db-intro.html

http://itic.ioc-unesco.org/index.php?option=com_content&view=article&id=1164&Itemid=2031

https://science.howstuffworks.com/nature/natural-disasters/tsunami3.htm

https://www.npr.org/2011/03/18/134600508/history-of-tsunami-the-word-and-the-wave

https://en.wikipedia.org/wiki/Tsunami

https://iotic.ioc-unesco.org/what-causes-tsunami/

http://tsunami.org/what-causes-a-tsunami/

120: When did the British empire end?

https://www.theweek.co.uk/tags/british-empire

https://en.wikipedia.org/wiki/British_Empire

https://www.politico.com/magazine/story/2014/08/the-sad-end-of-the-british-empire-110362/

https://history.state.gov/milestones/1945-1952/truman-doctrine

https://www.wealthandpower.org/part-4/51-collapse-of-the-british-empire

https://www.worldatlas.com/articles/reasons-why-the-british-were-successful-in-expanding-their-empire.html

https://www.historic-uk.com/HistoryUK/HistoryofBritain/Timeline-Of-The-British-Empire/

121: How does a nuclear bomb work?

https://cnduk.org/how-do-nuclear-weapons-work/

https://nrl.mit.edu/reactor/fission-process

https://www.nde-ed.org/Physics/AtomElements/stableunstableatoms.xhtml

https://www.epa.gov/radtown/radtown-radioactive-atom-activity-4-atomic-stability

https://www.wtamu.edu/~cbaird/sq/2013/06/07/why-do-atoms-always-contain-the-same-number-of-electrons-and-protons/

https://www.wtamu.edu/~cbaird/sq/2013/08/08/why-dont-electrons-in-the-atom-enter-the-nucleus/

https://www.visualcapitalist.com/science-of-nuclear-weapons/

https://science.howstuffworks.com/nuclear-bomb.htm

https://www.atomicarchive.com/science/fission/little-boy.html

122: Why is Washington DC the capital of the United States?

https://en.wikipedia.org/wiki/History_of_the_United_States

https://washington.org/DC-information/washington-dc-history#

https://www.history.com/news/how-did-washington-d-c-get-its-name

https://en.wikipedia.org/wiki/Washington,_D.C.

https://constitutioncenter.org/blog/how-philadelphia-lost-the-nations-capital-to-washington

https://constitutioncenter.org/the-constitution/articles/article-i

https://en.wikipedia.org/wiki/Philadelphia

https://www.yorkcity.org/about/history/

https://en.wikipedia.org/wiki/Thirteen_Colonies

https://www.ushistory.org/us/14d.asp

https://www.battlefields.org/learn/articles/early-capitals-united-states

123: Can you eat the skin of all fruit and vegetables?

https://www.neogen.com/neocenter/blog/science-why-are-fruits-so-colorful/

https://en.wikipedia.org/wiki/Peel_(fruit)

https://www.eater.com/ad/21560922/science-behind-peels-apeel-coating

https://www.thekitchn.com/most-nutrients-in-fruits-vegetables-are-found-in-the-skin-fact-or-fiction-185491

https://www.yummly.com/dish/679008/peel-this-not-that-a-quick-fruit-and-vegetable-guide

https://extension.psu.edu/fruit-quality-how-do-fruit-get-their-flavor

https://www.ehow.com/info_7755421_happens-after-pollination-flowers.html

https://www.twinkl.jp/teaching-wiki/ovary-plant

https://www.treehugger.com/poisonous-fruits-and-vegetables-avoid-4858734

https://www.nybg.org/blogs/science-talk/2014/08/what-is-a-fruit/

https://www.webmd.com/food-recipes/ss/slideshow-toxic-foods

124: How does computer encryption work?

https://nordpass.com/blog/brute-force-attack/

https://the-axiom.uk/how-long-would-it-take-you-to-crack-the-enigma-machine/

https://en.wikipedia.org/wiki/Cryptanalysis_of_the_Enigma

https://brilliant.org/wiki/caesar-cipher/

https://cloud.google.com/learn/what-is-encryption

https://mashable.com/article/why-should-we-care-about-prime-numbers

https://www.scienceabc.com/innovation/how-are-prime-numbers-used-in-cryptography.html

https://www.livescience.com/34526-prime-numbers.html

https://www.splashlearn.com/math-vocabulary/multiplication/factor

125: How do fluorescent lights work?

https://www.safeopedia.com/definition/9067/inert-gas

https://en.wikipedia.org/wiki/Noble_gas

https://en.wikipedia.org/wiki/Fluorescent_lamp

https://home.howstuffworks.com/fluorescent-lamp2.htm

https://lessismore.org/materials/102-fluorescent-light-tubes/

http://www.lamptech.co.uk/Documents/FL%20Gases.htm

https://edisontechcenter.org/Fluorescent.html

https://www.brubakerinc.com/why-does-my-fluorescent-light-make-a-humming-sound/