Sink & Float Snacks

Science
Time 30 minutes
Age 5-7
Group Size 4 or more
Tags Buoyancy, Sink And Float

Go ahead—play with your food!

Learning how to make thoughtful predictions and to test those predictions are skills children will need as they learn more and more complex science content. This simple experiment gives them that opportunity while also introducing principles of buoyancy.

Preparation

Purchase a variety of fruits and vegetables—try to have a mix of sizes and shapes. Fill the bin or tub with water. If you have a cart or dolly or something that rolls, it will make it much easier to transport the heavy bin to and from a sink. You might also do this activity outside, especially if you have a faucet with a hose that you can use. When you are finished, you can then simply turn the bin over to empty out the water.

Sink & Float Snacks
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Suggested Materials

  • Large bin or tub at least 12-inches deep (clear if possible)
  • A variety of fruits and vegetables (10 or more)
1

Make it Matter

Opening Discussion

Ask your children what makes some things float and some sink. Are there some things that sink even though it seems like they should float? How about things that float but it seems like they should sink?

The Challenge

Can you predict which of these foods will sink and which will float?

2

Make it Happen

Doing the Activity

  1. Place all of the fruits and vegetables on a table and ask your students to gather around it. Show them the items, and ask them to predict which ones will sink, which will float, and which they are unsure about. Write down the results, or separate the food into a “sink” pile, a “float” pile and a “not sure” pile.
  2. One at a time, have each child pick a fruit or vegetable, and let them place it in the water to see if it sinks or floats. Before they drop it in the water, remind them of what the group had predicted for that item.
3

Make it Click

Let’s Talk About It

Place the food that sank together in one area on a table and the food that floated together in another. Are there any similarities among the two groups? Refer to the predictions that the children made before the experiment. Do any of the results surprise them? Is there anything they could observe about the different items that might explain why some foods sank and some floated?

4

Make it Better

Build On What They Talked About

If time allows, cut open some of the fruits and vegetables to examine the insides. Does this give you anymore clues as to why some food sank and some floated? Are there other foods they might like to try?

Suggestions

  • Some fruits and vegetables will sink or float because of their shape, others may sink or float because of how dense they are, and still others may sink or float because of what they are like on the inside (some foods may have more air pockets inside them than others).
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