Experiment 1: Will It Float?
This experiment uses a knife. Ask an adult for help!
Materials:
Drinking glass
Water
Package of fresh cranberries
Package of dried cranberries
Knife
Hypothesis table
Procedure:
Make a hypothesis: Do you think a fresh cranberry with float or sink when placed in water? Why?
Fill a tall drinking glass 3/4 of the way with water.
Add a small handful of cranberries to the water.
Observe: Did they sink or float? Was your observation correct?
Find out why! Remove the cranberries and cut one or more in half. You should see four hollow air pockets in each half of the cranberry. These air pockets are what allowed the cranberry to be lighter than the water and float. This is called buoyancy.
Make another hypothesis: Do you think half a fresh cranberry will float or sink when placed in water? Why?
Add the half cranberries to the water.
Observe: Did they sink of float? Was your observation correct?
Find out why! The air pockets allow the half cranberries to act like little boats and float.
Take the half cranberries out of the water.
Make another hypothesis: Do you think dried cranberries will sink or float when placed in water? Why?
Add a small handful of dried cranberries to the water.
Observe: Did they sink or float? Why?
Find out why! Take a dried cranberry out of the water and cut it in half. Because it is dried, it doesn’t have air pockets anymore. This makes the dried cranberry heavier than the water.
| Fresh Cranberry x Water | Dried Cranberry x Water | Dried Cranberry x Clear Carbonated Beverage |
Hypothesis |
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Why? (my guess) |
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Find Out Why (the answer) |
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Experiment 2: Dancing Cranberries
Materials:
Drinking glass
Clear carbonated beverage (like sparkling water or Sprite)
Package of dried cranberries
Hypothesis table
Procedure:
Fill a tall drinking glass 3/4 of the way with a clear carbonated beverage.
Add a small handful of the dried cranberries to the glass.
Observe: What happens to the cranberries?
Find out why! The dried cranberries have lost their air pockets, so they will start to sink, because they are heavier than water but then the bubbles from the carbonation in the drink will stick to the cranberry and make it lighter, causing it to float to the surface. When the bubbles reach the top and pop, the cranberry will sink again. This creates a cycle that makes the cranberry look like it’s dancing!