Density

Density

Unit: Physical Science

2^nd Grade

Big Idea: Density

Focus Question: How does density affect the way different liquids ad material interact with each other?

Launch/Hypothesis/Prediction:

K	W	L

            If we pour oil into the jar of water, it will float above the water. If we pour corn syrup into the jar or water, it will sink below the water. If we pour corn syrup, oil, and water into the jar, they will not mix together, but will separate. If we drop the marble into the jar, it will sink. Corn syrup will sink. Oil will float. Both balls will sink to the bottom.

Materials:

• Clear cups
• Water
• Food coloring
• Corn syrup
• Vegetable oil 
• Marbles/rubber balls/small containers
• Group Container for supplies

Planning:

            First, we poured the water into the cup. Next, we poured the corn syrup into the cup and observed how it reacted with the water. Then, we poured the vegetable oil into the cup and observed how it reacted with the corn syrup and water. Last, we dropped the marble and then the rubber ball in the cup to see if it would sink or float.

Data:

	What happened? Sink or float in water?
Corn Syrup	Sank to the bottom
Oil	Floated to the top
Marble	Sank to the very bottom
Rubber Ball	Floated; less dense than water, more dense than oil

Claims/Evidence:

            We found that corn syrup is the most dense because it went to the bottom of the cup. Liquids that are less dense than water will float above it.  Liquids that are denser than water will sink below it.  Oil is less dense than water, and therefore, floats on top of it. We found that the marble has a greater density than water because the marble sank to the bottom of the cup. We found that the rubber ball has less density than the other liquids because it floated on top.

Conclusion/Reflection:

            We discovered that density affects the way different liquids mix, separate, and float or sink and how different materials float above or sink through the different liquids.

We discovered that when something has a high density, or is more compact, it will sink when placed in water. We discovered that when something has a low density, or is less compact, it will float when placed in water. What would happen if we stir everything together in the cup? What would happen if we added the liquids at the same time? Does everything have density? What other objects would float in water? In oil?

            Now we are thinking how can we change something to be more dense? We had a bottle top lying around so we tested it in our liquids and it floated. When we added water to it and put it in our liquids, it sank a little bit and then floated back to the top. We also wonder what other things would float in water including types of liquid. We could improve this lab by comparing and contrasting more materials or liquids. It may also be helpful to weigh the items before putting them in the cup or mixing them and watching them separate to see if weight has something to do with density. Someone told me that density is m/v….I wonder how I can see what that measurement looks like in an investigation!