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What’s the difference between global warming and the greenhouse effect?
─Sofia

Answer: The greenhouse effect is created because certain gases sent into our atmosphere, such as carbon dioxide, allow radiation from the sun to pass through the earth’s atmosphere, but prevent a portion of the infrared radiation from the earth’s surface and lower atmosphere from escaping into outer space. This process occurs naturally; without it our planet’s temperatures would be about 60 degrees cooler! Life as we know it simply would not exist without the natural greenhouse effect. However, many scientists believe global warming is happening because the greenhouse effect has become intensified by human activities (primarily the burning of fossil fuels), which add more carbon dioxide and other gases to the atmosphere and increases the warming process.

I once saw a pair of shoes hanging from a power line. Why didn’t the shoes get burned up by the electricity in the line?
─Will

Answer: Shoes hanging on a power line don’t get burned for the same reason that birds standing on a power line don’t get shocked: they don’t give electricity a path to the ground, so electricity stays in the line and does not go through them. But if the shoes were to touch a power line and a power pole at the same time, they would provide a path to the ground and would get blasted with electric current. It wouldn’t be pretty!

By the way, if you ever see someone throwing shoes up onto a line, tell them to stop! The shoes can damage the power line, or someone trying to get the shoes down could be seriously shocked or even killed.

Is it true that cars can someday run on cow manure?
─Griffin

Answer: Yes! Manure can be made into a gas containing methane. (Methane is the same energy-rich gas found in natural gas.) Certain types of bacteria emit this gas as they consume manure collected in special air-free tanks. The mixture of gases produced in this way, called biogas, can then be used in some modified car engines instead of gasoline, or burned in a boiler to generate heat or electricity.

Do electric eels really create electricity?
─Elena

Answer: Yes! An electric eel uses chemicals in its body to manufacture electricity. A large electric eel can produce a charge of up to 650 volts, which is more than five times the shocking power of a household outlet.

When a circuit is open, do electrons go backward, or do they just stop?
─Alex

Answer: Neither! In the wires of an electrical circuit, the electrons are always jiggling around. When a circuit is closed to run an appliance or a light bulb, the electrons jiggle a lot and travel through the wire. When the circuit is open, all the electrons just jiggle where they are—kind of like running in place.

Why didn’t Ben Franklin get killed when he tied a metal key to a kite string and flew the kite in a thunderstorm?
─Tyler

Answer: Ben Franklin’s famous key did give off an electric spark. But lucky for Franklin, the kite was just drawing small electrical charges from the air. If the kite had been struck by lightning, Franklin would have been killed!