Choose the sheet for the learner's age. Each prints on a single page. Build the project first, then fill it in together.
Ages 5-7: Draw & tell
Name: ______________________Date: ____________
Homemade Science with Bruce Yeany · Crushing Cans with Water · Ages 5-7
The Squished Bottle
Watch the bottle closely when the pencil comes out.
1. Guess first. When the pencil comes out, the bottle will...
◯ Stay the same◯ Get squished
2. Draw your bottle after the water ran out. Draw arrows showing the air pushing on it.
3. Where did the water go?
◯ Into the bucket◯ Into the air
4. I held the bottle up high. It squished...
◯ More◯ Less
5. What squished the bottle?
Ages 8-10: Predict, test & record
Name: ______________________Date: ____________
Homemade Science with Bruce Yeany · Crushing Cans with Water · Ages 8-10
How High Makes It Crush?
Predict, then test the same bottle at different heights above the bucket.
1. Predict first: which will crush the bottle more?
◯ Bottle held just above the bucket◯ Bottle held high above the bucket◯ Both the same
2. Refill the bottle and tube each time. Measure from the bucket's water to the bottle.
Where I held the bottle
Height (feet)
How much it crushed (none / a little / a lot)
3. What did you find out?
4. When I pinched the tube shut, the crushing...
◯ Kept going◯ Stopped
5. Why do you think the end of the tube has to stay under water?
Ages 11-14: Explain & design your own test
Name: ______________________Date: ____________
Homemade Science with Bruce Yeany · Crushing Cans with Water · Ages 11-14
Crushing with Hydrostatic Pressure
Use air pressure and the weight of water to explain and predict the crush.
1. Use the words air pressure and hydrostatic pressure to explain why the bottle crushes.
2. Every 2.3 feet of water column lowers the pressure inside by about 1 psi. If the bottle is 4.6 feet above the bucket, how much lower is the pressure inside? Show your work.
3. Bruce swapped a small bottle for a one-gallon can at the same height. The pressure drop inside was...
◯ Bigger for the gallon can◯ Smaller for the gallon can◯ About the same
4. Bruce used a wider hose. What changed?
◯ The can crushed harder◯ The can crushed faster◯ Nothing changed
5. Plan a fair test of how height affects the crush.
What I change
What I measure
What I keep the same
6. Why could you never crush anything harder by going higher than about 34 feet?
7. Where else does air pressure push a liquid or squeeze a container? (Hint: think about a drinking straw.)
Answer guide for grown-ups
Homemade Science with Bruce Yeany · Crushing Cans with Water · Answer guide
Answer guide
Ages 5-7: The Squished Bottle
Get squished.
Look for arrows pointing in at the bottle from all sides.
Into the bucket.
More.
The air (air pressure) pushing on the outside.
Ages 8-10: How High Makes It Crush?
Open answer: look for effort and careful observation.
Open answer: look for effort and careful observation.
Any answer matching their data. Higher above the bucket should crush the bottle more.
Stopped.
If the end comes out, air can get up the tube into the bottle to take the water's place, so the pressure inside stays the same as outside and nothing gets crushed.
Ages 11-14: Crushing with Hydrostatic Pressure
The water hanging in the tube is pulled down by gravity, and no air can get in to replace it, so the hydrostatic pressure inside the bottle drops below the outside air pressure. The outside air pushes harder than the inside and crushes the bottle.
4.6 / 2.3 = 2, so about 2 psi lower (about 12.7 psi inside instead of 14.7).
About the same: only the height of the water column matters, not the size of the container.
The can crushed faster. A wider hose drains it faster but does not lower the pressure more.
Change: the height above the bucket. Measure: how much the bottle crushes (or how fast). Keep the same: the bottle type, tube, how full the bottle and tube are, the bucket water level.
At about 33.9 feet the water column weighs as much as the whole atmosphere (14.7 psi), so the pressure inside reaches nearly zero, a vacuum. Going higher just leaves an empty space at the top; the pressure can't go below zero.
Drinking through a straw (air pushes the drink up), a water barometer, a suction pump that can't lift water more than about 34 feet, or a juice box that crumples as you drink.