MIND TREKKERS
Can Implosion Lesson Plan
Amount of time Demo takes: 3-4 minutes
Materials (be as thorough as possible):
1. Hot plate, bunsen burner, skillet, or other heating agent
2. Cans (pop cans, Monster cans, Yoohoo cans, etc.)
3. Tongs
4. Cold water
5. Paper towels
6. Heat-resistant gloves
7. Ice
Set up instructions:
1. Plug in the heat source.
2. Acquire a bucket or other container of very cold water.
SAFETY!
1. Use appropriate care when using the hot plate and heated cans. Students should not handle hot
materials.
Lesson’s big idea
● Gases react strongly to changes in temperature -- when they are heated, they expand greatly,
and when cooled they contract rapidly. These immense changes in pressure can cause the can to
implode.
Background information
1. As the can is heated, the water within boils into a vapor (see below). During this process, the
vapor pushes out the air that had been in the can previously. When the can was placed upsidedown in the water, the vapor rapidly condensed back to a liquid -- liquid molecules are much
closer together than gas molecules and take up less space (by a factor of ~1000).
2. Steve Spangler tells it best: “This small amount of water cannot exert much pressure on the
inside walls of the can, so the pressure of the air pushing from
the outside of the can is great enough to crush it. The sudden
collapsing of an object toward its center is called an implosion.
Nature wants things to be in a state of equilibrium or balance.
To make the internal pressure of the can balance with the
external pressure on the can, the can implodes.”
3. About phase shifts between solids, liquids, and gases: the heated
water in the can is vaporized into a gas. When it is cooled, the
vapor condenses into its liquid form. There are other phase
changes, but they are not used in this experiment (see diagram at
right).
4. If you can, watch very carefully and notice that a small amount of water is actually “sucked”
up into the can. It turns out that the difference in pressure between the inside of the can and the
outside air is so great that it pushes water up into the can!
Instructional Procedure
1. Don safety gloves (if desired).
2. Put a tablespoon or so of water into the can.
3. Using the tongs, place a can on the heat source. Talk to students about what is happening within
the can -- air is being heated up, water is boiling, expanding, etc.
4. After approximately 30 second to a minute, you should begin to see vapor. Allow the can to
continue heating for a minute or so after this happens.
5. Be sure to read this step through before performing it: using the tongs, you will remove the
can from the hot plate and plunge it into the water.
a. Using the tongs, get a good grip on the can near the bottom. Do so in a way such that
your hand is palm-up. In one fluid motion, lift the can, turn it upside down, and submerge
it in the water.
6. The can should quickly collapse upon itself. Once the can has cooled, you can take it out, show it
to the students, and let them handle it.
Assessment/sample questions you can ask:
1. What caused the can to collapse?
2. Which takes up more space: gases or liquids? Liquids or solids?
3. What is it called when gases change to liquid state?
Clean Up
● Turn off the heat source and let it cool before packing.
● Wipe up any spilled water and empty the bucket.
● Dispose of mangled cans.
References
● Steve Spangler: http://www.stevespanglerscience.com/experiment/incredible-can-crusher
National K-12 Physical Science Standards
● Levels K-4: Light, heat, electricity, and magnetism
● Levels 5-8: Properties and changes of properties in matter
● Levels 9-12: Structure and properties of matter, Interactions of energy and matter