Cranberry Float and Bounce Test

What you need

• Berries, 15 to 20 fresh cranberries and 1 blueberry
• Water, 1 large bowl
• Plate or tray, 1 tray
• Paper, 1 sheet
• Pencil, 1
• Grapes, 1
• Raisins, 1
• Bowl, 1 large
• Towel, 1, or a paper towel
• Knife, 1, for a grown-up
• Ruler, 1 (optional)
• Cutting board, 1, for a grown-up

How to do it

Grown-up prep: Wash the berries and set out the bowl, tray and paper. Keep the berries away from children under 3, as whole berries are a choking risk. Raw cranberries are very sour but safe to taste. A grown-up does the knife cutting.

1. Draw a table with columns for berry, floats, and bounces.
2. Drop five cranberries into the bowl of water and watch.
3. Guess, then test a grape, a raisin and a blueberry in the water.
   Ask: Which of these do you think will float, and which will sink?
4. A grown-up slices one cranberry in half across the middle. A grown-up does this
5. Look inside for the four small air pockets.
   Ask: Why do you think the air pockets help cranberries float?
6. Dry the berries, then drop them one at a time onto the tray.
7. Sort the berries into bouncers and duds.
8. Squeeze the duds to see if they are soft or bruised, then fill in your table.
9. Now test more berries or make a new guess! Which fruit will bounce highest?
   Ask: What other things in the kitchen do you think would float or bounce?

Play it again

• Bounce race: see which berry bounces highest or the most times.
• Mystery fruit: a grown-up chooses a new fruit and you predict float or bounce before testing.
• Squish check: sort berries by how firm they feel, then see if firm ones bounce best.