Children's Museum of Houston

What you need

• 3 film canisters or 3 same size travel containers
• Sand
• Tall clear container or aquarium
• Water
• Masking tape
• Marker

What you do

1. Fill the clear container almost full with water.
2. Using the masking tape and the marker, label the three film canisters as sink, float and neutral buoyant.
3. Select the film canister labeled “sink." Predict and add the amount of sand you think it will take to sink the film.
4. canister to the bottom of the clear container.
5. Test your prediction by placing the film canister in the water. Was there enough sand in the canister to make it sink?
6. Select the film canister labeled “float.” Predict and add the amount of sand you think it will take to simply float the film canister on the top of the water in the clear container.
7. Put the container in the water to test your prediction. Did the canister float?
8. Select the film canister labeled “neutral buoyant.” Predict and add the amount of sand you think it will take for it to float in the middle of the water when placed in the container.
9. Test your prediction by placing the film canister in the water. Did it float in the middle of the container?

What you ask

•  Why did you have to change the weight of each film canister to accomplish all three goals?
• Would it have made a difference if we used a bigger or smaller film canister?
• Does an object with more ‘stuff’ in it have a higher or lower density?

Did you know?

What’s next?