Density is the weight of an object or substance in relation to its mass. This project demonstrates the relative density of each substance by adding objects of different weight to see how the object added absorbs or repels the fluid. You will need the following items to complete this project: 3 clear drinking glasses, corn syrup, water, vegetable oil, a grape, a small piece of cork and a coin. Fill one glass with corn syrup, one glass with water and the last glass with vegetable oil.
Begin by dropping pieces of cork into each glass. Have students observe the objects and take notes on how whether the cork floats or sinks into the liquid. Keep a record of how long it takes each piece to begin to sink. Remove corks from glasses and repeat these steps with grapes, and then coins. The cork will float on all of the substances. The grape will sink in water and vegetable oil, yet float on the syrup. The coin will sink into all three liquids.
Rinse out each glass and add water until three-quarters full. Pour oil into one glass. Notice that the oil floats above the water. Add corn syrup to the glass. The corn syrup will slowly drop to the bottom of the glass. Explain to students how each substance's density is different. Vegetable is the least dense, therefore it will always float on top of water. Corn syrup is the most dense of the three, which is what causes it to sink below the water and oil.
To expand upon this learning experience, have each student create a data chart. Include the materials used, what happened to the objects added to fluids, how long it took them to sink, and which fluids had the most density. Use this chart to design a line graph explaining the data. Use color markers and construction paper to enhance the student's graphs. Mount data charts and line graphs on a presentation board with a glue stick.