Why do they put fluoride in water? Not a lot of countries puts fluoride in their water supply, but those that do use fluoride, do it to strengthen people’s teeth and make them more resistant to tooth decay and cavities. There are two types of fluoridated water: artificial and natural. 5 countries in the world […]
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How many ice ages have there been? There have been five major ice ages through the history of our planet, but there have been several smaller ones as well. What is an ice age? An ice age is a period in time where the global temperature falls to the point where water freezes and ice
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What is wind chill? Wind chill is where the wind reduces the air temperature, making it feel much colder than it actually is. Wind chill can be deadly if you are not wearing the right clothing. The temperature for the day that you say in the newspaper or on the weather forecast of the TV
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Why are bird nests s strong? The way that birds build nests depends very much on the birds. Different birds use different materials, different methods, and some birds don’t even build nests at all. However, the nests that birds build in trees tend to be strong because of their saliva. Birds that don’t build nests
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Why is an atomic clock so accurate? Atomic clocks are accurate because atoms oscillate at a stable and predictable frequency. All clocks work by using the number of movements of something to calculate the passage of time. They do this by knowing how many movements of something equal a second and working from that. Mechanical
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Why is a pronghorn so fast? The pronghorn evolved to have phenomenal speed so that it could outrun predators that no longer exist. A pronghorn is a hoofed mammal that lives in Western and Central North America. It belongs to the artiodactyl family. This family contains antelopes, hippos, deer, giraffes, camels, and 265 other animals.
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What happened at Dunkirk? 338,226 British and French soldiers were evacuated from the beach at Dunkirk over the space of 8 days. That was far better than anyone in the British government expected, but about 20,000 soldiers died and 90,000 were captured by the Germans. Along with that, 300 ships were sunk, 100 planes were
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How are sellotape (Scotch tape), duct tape, stick glue, wood glue, and superglue different? All the types of glue have different chemical components and they are different in the way that they dry. They also stick or don’t stick to different things. Adhesive tape is called sellotape in the UK and Scotch tape in the
How could a whistle get free phone calls? Old telephone routing equipment worked on sound at a specific frequency. Some whistles blew at exactly the same frequency and could be used to trick the phone equipment. The people who were cheating the phone system called themselves “phreaks”, which was a combination of “phone” and “freak”.
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How do drones hover? Drones hover by using a mix of sensors to adjust their rotor blades. The majority of commercially available drones have four sets of rotor blades, one on each corner. This makes them much easier to control at low speeds and much more stable. The military have drones like this, but they
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