Why can we only hear certain frequencies? Our cochlea is only stimulated by frequencies between 20 Hertz and 20,000 Hertz. First, let’s look at how we actually hear. Our ear is a detector for sound waves. It is shaped to funnel them into the ear canal, which ends in the eardrum. The sound waves make […]
#304 Why can we only hear certain frequencies? Read More »
Could nuclear fusion power the Earth? Yes, but not in this half of the 21st century. Nuclear fusion and nuclear fission are the two ways we can get energy out of an atom. Nuclear fission is the easiest of the two for us to perform on Earth. In nuclear fission, a neutron is fired at
#296 Could nuclear fusion power the Earth? Read More »
How does a rocket engine work? Rocket engines work because of Newton’s third law of motion. Newton’s third law of motion states “to every action there is always opposed an equal reaction; or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.” Or, in other words, for
#293 How does a rocket engine work? Read More »
I learned this today. Why are some places more humid than others? It is because they are closer to a large, warm body of water, which causes warm winds and warm air can carry more water vapor than cold air. What is humidity? Humidity is the concentration of water vapor in the air. The air
#283 Why are some places more humid than others? Read More »
I learned this today. How does fly spray work? By blocking the insect from using its nerves to move its muscles. There are two kinds of fly spray. There are repellents, which are sprays you apply to your body to stop insects landing on you and biting. Then there are insecticide fly sprays that kill
#280 How does fly spray work? Read More »
I learned this today. How does a desalination plant work? A desalination plant makes freshwater from seawater by using reverse osmosis. Humans and animals obviously cannot drink salt water. Fish have adapted to be able to do it, but we have not. There is about 35g of salt in every liter of sea water. If
#278 How does a desalination plant work? Read More »
I learned this today. High energy radiation or long exposure to radiation can damage the DNA in cells and cause radiation sickness. What is radiation? Radiation is energy that radiates from a source and travels through space at the speed of light. It travels as a wave or as particles and has an electric field
#275 How does radiation sickness happen? Read More »
I learned this today. A superfluid is a point where matter behaves like a fluid but has zero viscosity.A superfluid has no viscosity. That means it doesn’t have any friction and doesn’t lose energy. It appears to go against the laws of thermodynamics. If you stir a cup of coffee with a spoon and step
#265 What is a superfluid? Read More »
I learned this today. The aurora borealis are green, purple, pink, and blue because those are the colors given off when the different elements in the atmosphere are heated up. The aurora borealis is caused by electrically charged particles from space hitting the magnetic field in the upper atmosphere at a very high speed. The
#264 Why are the aurora borealis those colors? Read More »
I learned this today. A hand grenade works because the removal of the lever starts a series of steps that ends with an explosion. There are many different types of grenade. I am going to look at the fragmentation grenade. Most of us imagine the Mk 2 grenade when we think of a hand grenade.
#259 How does a hand grenade work? Read More »
