1The Invisible Giant All Around Us
Imagine you are standing at the bottom of a deep ocean, but instead of water, you are surrounded by a sea of air! This is exactly what happens on Earth every single day. Above your head, there is a giant column of air molecules stretching hundreds of kilometers into space. Because air has mass, all those molecules have weight, and they push down on us with a force called atmospheric pressure. Even though you can't see it, this invisible giant is pressing on every square centimeter of your body with the weight of a one-kilogram pineapple. That means if you hold out your hand, you are technically carrying the weight of several heavy bags of sugar just in the air above your palm!
2Why Don’t We Get Squished?
If there is so much pressure pushing on us from every side, why don't we get squished like a bug? It is because our bodies have pressure inside them that pushes back out! Our lungs, blood, and cells are all filled with fluids and gases that balance the force of the atmosphere. It is a perfect tug-of-war where neither side wins. However, when we change that balance, amazing things happen. Scientists can show this by removing the air from inside a metal soda can using steam. Without the air inside to push back against the outside world, the invisible giant of atmospheric pressure crushes the thick metal can instantly, turning it into a crumpled mess in the blink of an eye!
3Science in Your Bathroom
You can see this "Invisible Squeeze" in action every day with a simple suction cup. When you press a suction cup against a window or a smooth tile, you are actually squeezing all the air molecules out from the space underneath it. Because there is almost no air left inside to push back, the heavy air in the room slams the cup against the glass and holds it there with incredible force. You might also feel air pressure changing when your ears "pop" in an airplane or a fast elevator. That is just your body adjusting to the thinner air higher up, where the invisible giant isn't quite as heavy as it is on the ground!
