Air .... It's Everywhere Air doesn't taste like anything. You can't touch it, or smell it, or even see it, yet it is all around you and it contains the oxygen you need to survive. Have you ever wondered how much air weighs? The air in a large room weighs more than you! (160 pounds or 72 kilograms is about the size of an adult.) Warm air is lighter than cold air. When air is heated, it rises and cold air moves in to replace it. Birds use rising currents of warm air to float up into the sky! Warm air also takes up more space than cold air. As air is heated, it expands (takes up more space). Want some proof? Try putting a blown up balloon in a warm place, like above a radiator, and see what happens. Hint: POP!!!!!Although you cannot feel it, air is constantly pressing against your skin. In fact there is 14 pounds of air pressing against you RIGHT NOW. A very FAT cat could weigh 14 pounds! You don't notice it because you are used to it, and because the air doesn't touch you in just one place. It's touching all of you at once, just like water does in a swimming pool. That 14 pounds of air is called air pressure. It is caused by the atmosphere, which is a layer of air that surrounds the earth. Moving air, like wind, has less air pressure, or pushing power than still air. Wind is caused by changes in the temperature and pressure. When air is trapped and tightly packed inside of a small space (compressed), it has great strength. The more air you pack into a space, the more it pushes against the walls, trying to get out. HEY! IT'S CROWDED IN HERE!!!Air can be strong enough to hold up a car! That's what the tires are filled with. Without air there would be no sound. A vibration happens when something makes the air move up and down. The up and down movement is called waves. If the vibration reaches your ears, it makes the ear drums vibrate. When your ear drum vibrates, you hear the sound. Experiment with this concept!Where's The Air?Since we can't see, smell, taste, or hear air, it is easy to forget it exists. When you look inside of an empty bowl, do you think, "There is nothing inside of the bowl", or "The bowl is filled with air!" Air fills up all those spaces that seem empty. Here's an experiment to prove it. MATERIALS:
WHAT TO DO:
HOW IT WORKS:The bottle was full of air. By putting modeling clay around the opening, you stopped the air from escaping, so there was no room for the water. When you put a hole in the modeling clay, the air had a way to get out and make room for the water. |
