Bill Nye The Science Guy
Disney Educational Productions
The Science Guy is starting to feel the pressure.
When you push something, you’re using pressure. Pressure depends on two things – the power of the push and the area that’s being pushed on. A push on a small area makes more pressure than the same size push on a big area. Pushing hard on something creates more pressure than a little nudge, naturally.
Some things have their own pressure built in. Liquids and gases always have pressure, and they press in all directions. Think about a balloon. Air inside the balloon pushes on all sides of the balloon at once – up, down, left, right – in every direction. Liquids like water do the same thing. When you fill a glass with water, gravity pulls it down making pressure in the glass. The water pushes on the bottom and the sides of the glass. Water pushes up, too – that’s why a cork pushed underwater pops up to the surface. Pressure in liquids and gases comes in handy for stuff like air mattresses, bike tires, hovercrafts, and drinking straws. When you suck the air out of your mouth, air pressure above the glass or cup pushes a milkshake into your mouth.
Bill Nye – he’s not a pushy guy, he just wants you to learn about pressure.