Activity
Under Pressure
Before 17th century mathematician Blaise Pascal described the mechanics, people thought a "magician" could "command" the bottle to sink. Your child will love learning the science of a simple "trick" that has been astonishing onlookers since Medieval times.
What You Need:
- Small glass bottle (vanilla bottle, medicine bottle, eye-dropper bottle, nail polish bottle)
- Styrofoam craft ball (not packing Styrofoam)
- Knife
- Deep glass vase
- Plastic lid
- Water
- Towel
What You Do:
- Help your child gather supplies and set up a work area by placing a towel on the kitchen counter. You'll need a deep, wide-mouth vase or jar, a plastic lid to cover it, and a small glass bottle that fits inside of it.
- Have your child cut a Styrofoam "cork" for the inner bottle. It doesn't have to be round. The cork should show 1/4" above bottle rim.
- Invite your child to add a little water to the inner bottle and cork it.
- Your child should fill the vase with water, place inner bottle in it and observe. If bottle sinks, he can shake a few drops of water out of it. If it "wallows," he can add a few drops of water to coax it upright.
- When the bottle floats just so, your child can re-fill the vase, if needed, to the very top. Then, have your child place a plastic lid over the vase mouth to seal it.
Invite your child to press on the lid. Pressing increases air pressure. When air trapped in the bottle compresses, it no longer provides enough buoyancy to float. The bottle sinks. When pressure is released, a few drops of water are forced into the bottle to replace air, undoing the equilibrium. (To make it float again, shake out the few drops.)
Related learning resources
Barometric Pressure
Science project
Barometric Pressure
Science fair project examining barometric pressure, and how it can be used to predict the weather. How does atmospheric pressures relate to weather conditions?
3rd grade
Science
Science project
All About Air Pressure
Science project
All About Air Pressure
The goal of this science fair experiment is to demonstrate the effects of air pressure on objects and analyze applications of air pressure principles.
3rd grade
Science project
Principles of Air Pressure
Science project
Principles of Air Pressure
The objective of this science fair project is to examine the basic principles of air pressure using simple materials like a balloon, straw and string.
4th grade
Science project
Speaking Under Water
Science project
Speaking Under Water
Using an empty tennis ball can and a swimming pool, you will determine if it's possible to have a conversation under water.
3rd grade
Science project
How Does Pressure Change Minerals?
Science project
How Does Pressure Change Minerals?
In this science fair project, students learn how pressure can make the minerals in a rock line up in the same direction and form bands and foliation.
1st grade
Science project
Creative Writing: Under the Sea
Worksheet
Creative Writing: Under the Sea
Your young writer can write their own under the sea story with this creative writing prompt.
5th grade
Reading & Writing
Worksheet
How Do Heat and Pressure Create Metamorphic Rocks?
Science project
How Do Heat and Pressure Create Metamorphic Rocks?
In this experiment, students will discover how heat and pressure turn clay into slate, phyllite, and finally schist.
5th grade
Science project
Air Pressure
Worksheet
Air Pressure
...air pressure, what is air pressure, air science, learn about air, earth science...
5th grade
Reading & Writing
Worksheet
Are There Other Animals that Glow Under a Black Light Besides Scorpions?
Science project
Are There Other Animals that Glow Under a Black Light Besides Scorpions?
Check out this cool science fair project idea to explore which other common animals besides scorpions glow under a UV Black light.
4th grade
Science project
Building Up the Fizz in Soda
Science project
Building Up the Fizz in Soda
Examine the effect of pressure on carbonation in soda.
Middle school
Science project
Bernoulli's Principle Experiment
Science project
Bernoulli's Principle Experiment
In this Bernoulli's Principle experiment, you'll learn how an increase in the speed of a fluid, like air, decreases pressure.
5th grade
Science project
What is Condensation?
Science project
What is Condensation?
Little mad scientists will learn about condensation, states of matter, and air pressure by conducting this cool science experiment.
5th grade
Science project