⚡ Energy

Energy is what makes things able to move, change, glow or grow, and it shows up in lots of different forms, like light, heat, sound and movement. Nothing can happen without some energy behind it, even a plant growing taller needs energy it captured from sunlight. Scientists think of energy as something that can move from place to place and change form, but the total amount never really goes away.

Energy comes from many sources, like the sun, food, wind, moving water and stored fuel, and it is always moving from one place or thing to another rather than being made from nothing. The sun is the starting point for most energy on Earth, plants capture sunlight and turn it into the energy stored in food, which then passes on to whoever eats it. Even wind and moving water get their energy indirectly from the sun heating the air and driving the weather.

Energy always moves from one form to another instead of vanishing, this is a rule scientists call the conservation of energy. When a ball stops bouncing, its movement energy did not disappear, it turned into heat and sound instead, spread out into the ball, the floor, and the air around it. This rule is considered one of the most solid, unbroken rules in all of science, and scientists use it to figure out exactly where energy goes in any situation.

A battery stores energy inside chemicals that are just waiting to react, and when you connect it in a toy or device, those chemicals release their energy as electricity flowing through a circuit. Once the chemicals inside have finished reacting, the battery runs out and cannot push electricity anymore. Some rechargeable batteries can have their chemical reaction reversed by plugging them into a charger, which lets them be reused thousands of times before wearing out.