How do batteries work?

Imagine having to keep anything that uses batteries plugged into the wall for it to work. Cords would be stretched out all over your home. Batteries allow us to make things like a television remote mobile. We can pick them up and move around without tripping over cords. How do batteries make this possible?

Batteries are a small container full of special chemicals that make electricity. Batteries have a positive end and a negative end. A barrier in the middle separates these ends from each other. When the chemicals inside react, they make a tiny particle called an electron. The electrons have a negative charge and collect together at the negative end of the battery. The electrons get rather crowded at the negative end and need to move to the empty positive end. To do this, a wire must be connected to each end, like when you put the battery in the TV remote. The electrons move through the wire and around the barrier. Think of a football running back running around the defensive end rather than bouncing off him and falling down. When the electrons move to the positive end, they flow like a river through the wire. This flow is electricity and it powers the devices we use. And that’s how batteries work.

How does a boat float?

A boat made of steel floats on water, but a block of steel sinks in water. How does the boat float instead of sinking to the bottom?

In ancient Greece, a scientist by the name of Archimedes (Ark-eh-meed-eez) came up with the principle, creatively called the Archimedes Principle, which explains how a boat floats.

If you fill a bathtub and sit in it, the water in the tub rises. This is because you displaced, or moved, the water, and it had to go somewhere. The amount of water you displaced weighs the same as the weight you put in the water. The same is true for a boat in the water.

If a boat weighs 1,500 pounds, it will displace 1,500 pounds of water. So long as the boat displaces 1,500 pounds of water before the boat is submerged, the boat floats.

So how does the water “know” when 1,500 pounds has been moved out of the way? Floating actually has more to do with the amount of pressure rather than weight. The boat puts pressure on the water, and the water puts pressure on the boat. The upward pressure pushing on the bottom of the boat is what causes it to float. Each square inch of the boat that is underwater has water pressure pushing it upward, and this combined pressure causes the boat to float.