Pressure Science Activity with Ketchup Packets
If you ask a kid about their favorite condiment, and the answer is likely to be ketchup.
But did you know ketchup is more than just a topping on a hot dog? Yep, your child (or students) can learn a little something about the interesting concept of pressure, with a little packet or two of ketchup. But first, let's learn a little more about pressure:
Example of a bottle exposed to different levels of air pressure.
What is pressure?
"Pressure" refers to the weight something puts on another thing. For example, air pressure refers to the weight of air on something. When you fill up a balloon with air— but don't tie it off— the pressure on the outside of the balloon forces the air inside of the balloon to come out (normally noisily, might I add). When you do tie off the balloon, the shape of the balloon when change shape if you press on it; that's because you are applying pressure to it. Push on the balloon too hard, and you'll pop the balloon, because you applied more pressure on the outside than there was on the inside of the balloon.
But the principles of pressure aren't relegated to air alone, what would happen when the contents of a sealed bottle? Let's take a look.
The Science Experiment
You've seen what happens to an empty bottle of water when exposed to different levels of air pressure, but what happens to a ketchup packet are met with increased pressure? Let's take a look:
What You'll Need:
- ketchup packets
- your foot (with a shoe on)
- paper towels (for clean up)
- Go outside on the sidewalk or your driveway.
- Place a ketchup packet on the ground.
- Stomp on the ketchup packet with your foot, and watch what happens.
- Clean up the mess with paper towels.
When you stomped on the ketchup packet a lot of pressure is exerted on the package. The force from the outside makes less room inside the packet. When you press hard enough on the packet, the contents (the ketchup) can't fit inside the packet, so it moves to a place where there is less pressure (outside the packet).
In the video below you'll see the great Bill Nye (the science guy) conduct a few experiments (and give explanations) as to what atmospheric pressure is, and how it works.