Energy FAQ (Frequently Asked Questions)


Have you ever wondered why shoes hanging on a power line don’t get fried? Or whether electric eels really create electricity? Now you can find answers to these and other energy-related questions.

We post new questions and answers regularly, so check back!


Click on a question to see the answer.

NEW! Why do I need to unplug my cell phone charger?

Answer: Cell phone chargers are known as "energy vampires." They suck energy when plugged in, whether or not a phone is connected to them. In fact, only 5% of the electricity used by most cell phone chargers goes toward charging a phone. The other 95% is wasted when they are left plugged into the wall! To prevent this energy waste, get yourself (and your family) into the habit of unplugging all chargers—including iPod chargers—when not in use.

What is an electromagnet?

Answer: An electromagnet is a magnet in which the magnetic field is produced by a flow of electric current. It consists of a coil of copper wire wrapped around an iron core. You can change (or stop) the strength of an electromagnet by adjusting the amount of electricity flowing through it.

Could a power line break and start a fire?

Answer: Power lines are securely attached to power poles with special connectors so they don't fall or break. However, in rare cases of extreme wind or heavy snow, a power line can come down and the electricity in it can shock or burn anyone or anything that touches it. This is why it's so important to stay indoors during and after bad storms, and why you should always stay far away from fallen power lines and call 911 to report them.

Why are people always talking about the dangers of lightning? Isn’t it a pretty unusual occurrence?

Answer: Not really—lightning strikes about 6,000 times per minute on our planet.

Can you see electricity flowing in power lines or electrical wires?

Answer: You can’t see electricity when it is flowing through a circuit. But if electricity leaves the circuit, as it does when someone is shocked, you can see a spark. The spark isn't electricity itself. It is a flame that occurs when the electricity travels through the air and burns up oxygen particles.

Does everything use energy?

Answer: Well, yes and no. Yes, because you need energy to make anything happen—it’s what makes anything and everything move, change, and/or grow. Everything that happens does so because of energy, and all living things use energy. But everything in the world does not use energy. For example, a rock on the ground and a car parked in a driveway do not use energy while they are sitting still. However, if you want to move the rock, or drive the car, you need to use energy to do that.

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?

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.

Do electric eels really create electricity?

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.

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

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!

When a circuit is open, do electrons go backwards, or do they just stop?

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.