Dancing Raisins

Dancing Raisins

Unit: Physical Science

2ns Grade

Big Idea: Density

Focus Question: Will the raisins float in water or soda?

Hypothesis/Prediction:

-       If we put the raisins in water, then they will float because they are light.

-       If we put the raisins in soda, then they will float because of the bubbles.

Materials:

            •Clear drinking glass

•Pitcher of Water

•Club soda (2 liter) (or Sprite)

•2-3 Raisins

•Dry Pasta

•Beads

•Buttons

•Paper Towels

•Science Notebooks

Planning:

            First we will place our raisins in the water and watch what happens to the raisin. Next we will place our raisins in soda and watch what happens to the raisin. Then we will put pasta in the water to see what happens when you put pasta in the water. Then we will put pasta in the soda to see what will happen to the pasta in the soda. 

Data:

Water		Soda
Raisins		Raisins
Pasta		Pasta

Claims/Evidence:

Claims (Predictions)	Evidence
If we put the raisins in water, then they will float because raisins are light.	The raisins sank in the water because they are denser than the water.
If we put the raisins in soda, then they will float because of the bubbles.	The raisins sank, rose and sank again in the soda. They sank because they were denser than the soda. They rose because the bubbles from carbonation attached to them until they reached the top. After the bubbles reached the top, the raisin sank back down to the bottom of the soda.

Conclusion/Reflection:

             In this investigation we learned that the sinking or floating of different solid objects in a liquid depends on the density of the solid object relative to the density of the liquid. If a solid object is less dense than a liquid, it will float. If the solid object is denser than a liquid, it will sink. The raisins in our investigation were denser than the water, so they sunk to the bottom of the cup. When the raisins are placed in the soft drink they initially sunk because they are denser than the soft drink. When carbon dioxide gas bubbles attach to the outside surface of the raisins, they act like “floaties” for the raisins. The raisins that attached were then less dense than the soft drink because they attached to the carbon dioxide bubbles. As the raisins rise to the top the bubbles escape into the air and the whole process starts again. We wonder what else might dance in the sprite. Pasta? Buttons? Beads?