字幕列表 影片播放 列印英文字幕 Hi everyone! I'm Jayde and today we're going to talk about energy! But what is energy? Well all around us are things that move - we can see cars driving, we can see people walking, we can see things moving around on TV - and if you look for a really long time, you might even see plants growing... very slowly of course! But what gives these things their ability to move? Well, the answer is energy! Energy is the power to move, the power to do work. Energy makes things happen all around us. Energy isn't something that we can see or hold or touch - it's sort of like the wind. You can't see the wind or hold the wind - but you can see the effects of the wind as it blows things around. Energy is the same - you can't see the energy but you can see energy moving things. You can see energy at work. There's two types of energy that you might notice around you - one type is moving energy - also called kinetic energy. Imagine you ride your bicycle up a hill - it takes a lot of energy to move your bike up the hill, and because the bike is moving - you're using kinetic energy. The bigger and heavier the bicycle, the harder you have to push and the more kinetic energy you need to make the bicycle move! The second type of energy is called stored energy, or potential energy. This is when something isn't moving right now, but it could move. It has the potential to move - which is why we call it potential energy. So, for example, if you're on your bike and you're at the top of the hill, you have to keep your brakes on, otherwise you'll roll down the hill. The bike has potential energy - or stored energy - energy stored in the bicycle, waiting to be used. As soon as you take the brakes off you begin to roll down the hill, and because now you and the bike are moving - that's called kinetic energy again. So energy is the ability to move against a force - whether you're actually moving right now or if you're holding on to that energy to move later. Now, I've talked about the two kinds of energy - kinetic energy and potential energy - let's talk about where energy comes from. Imagine you're riding your bike up the hill again. When you ride your bike your body is using energy that came from food. Humans get all their energy from food. Energy that's from food is called chemical energy because it comes from the chemicals in the food - that's why sometimes if you haven't eaten for a while you might get hungry or even hangry - and feel tired. It's a sign that your body is running out of chemical energy and it needs more, so it has the energy to do more exercise. But where does the food get its energy from? Here's a food you might know... a potato. This potato was once part of a potato plant - and plants get their energy from the Sun - in the form of light energy. So that's where plants and humans get their energy from... but what about your computer or your TV - where do they get their energy from? Well, computers and TVs and other appliances in your house get their energy from electrical energy. You might call it electricity. Electricity comes from power plants that make electrical energy by burning oil or coal, and they send the electricity to our home along wires. Some homes get their electricity from solar panels. Solar panels turn the light energy from the Sun into electrical energy that you can use in your home. So in this video we learned about the two kinds of energy: kinetic or moving energy, and potential or stored energy - and we also learned about the places where energy comes from. Whether your energy comes from food or from light or from electricity - all types of energy just mean the ability or the potential to move.