What makes rain smell? A combination of plant oils, bacterial spores, and ozone. Everything always smells very fresh after a rainfall and there is a word for it. Merriam-Webster defines petrichor as, “a distinctive, earthy, usually pleasant odor that is associated with rainfall especially when following a warm, dry period”. The word was invented by […]
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How does dry cleaning work? Clothes are soaked in a water-free liquid solvent. Dry cleaning is a way of washing clothes without water. At home, all of us wash our clothes in the washing machine using some kind of detergent and water. Inside the washing machine is something called an agitator. This is a drum
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Why do the leaves on a tree change color in the autumn (fall)? The leaves on trees change color in the autumn because the tree breaks down its own chlorophyll. Not all trees lose their leaves. Evergreen trees keep their leaves throughout the year. Trees that lose their leaves in the winter are called deciduous
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Why does smoke inhalation kill people? It reduces the amount of oxygen that the lungs can take out of the air and people die of asphyxiation. House fires are obviously dangerous, but most people who are caught in a fire don’t die from burns. In 2019, there were 3,704 deaths caused by fire in the
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Why are stealth bombers invisible? They are not completely invisible, but they are able to reduce the reflection of radar, infrared, visible light, and radio waves. The first stealth plane was the Lockheed F-117 Nighthawk built in 1981. It was an attack aircraft, not a bomber, but it was the first plane to make use
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What is the difference between snowflakes and hail? Snowflakes are made up of ice crystals and hail is a frozen raindrop. Hail are frozen raindrops. They are generally between 5 mm and 15 cm in diameter. Hail is not as common as snow and can only form in a thunderstorm. For hail to form there
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How does an air fryer work? A fan circulates hot air at high speed which cooks the food. Firstly, let’s look at how food cooks when it is fried. With deep-frying, food is submerged in oil that is heated to between 177 and 191˚C. That seems pretty hot, but it is far below the boiling
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What causes quicksand? It forms in saturated loose sand when the sand is suddenly agitated. Quicksand is an example of a non-Newtonian fluid. That means it is a liquid, but has the properties of a solid when the pressure applied to it changes. A Newtonian fluid is a liquid such as water that flows exactly
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What is in toothpaste? It usually has fluoride, abrasives, flavors, humectants, and detergents. So, what do all of these things do? Fluoride is a naturally occurring mineral. It can be found in most places on Earth, and it is also present in our bodies. Our bodies use it to strengthen our bones and teeth. Fluoride
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What are the four laws of thermodynamics? I didn’t know there were four laws until researching this. Thermodynamics is the study of the relationship between heat, temperature, and energy. The 0th law of thermodynamics states that if two systems are in thermodynamic equilibrium with a third system, the first two systems are in equilibrium with
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