Life Science Curriculum 8-12

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Submitted by: Jennifer Perry

Position: N/A

Institution: Azusa Pacific University

Title of Experiment: Density of Objects

Materials Needed:

1 clear jar (large enough to hold at least 6 cups of liquid)
2 cups of maple syrup
2 cups of vegetable oil
2 cups of water
Several small objects

Scientific Background of Experiment:

 Density is defined as mass per unit of volume or D=M/V. Mass is most commonly calculated in grams and volume is calculated in cm3. Mass is the amount of substance (matter) in an object, not the object's weight. So the weight of an object does not matter when determining the density.

In this experiment, you will be observing the different densities of random objects that you or your students can collect. You will be placing these objects in a jar that contains three liquids of different densities in it. The denser objects will fall down the farthest while the less dense objects will stay towards the top. In this way, you will be able to observe the densities of different objects by comparing them to the densities of the liquids.

Methodology:

Setup: Take the jar and fill it with the 2 cups of syrup, 2 cups of water, and 2 cups of vegetable oil. Allow it to settle. The syrup will stay at the bottom, the water in the middle, and the oil will surface on the top.

Gather: Find several small objects that you would not mind washing or throwing away later. Some good suggestions are paperclips, coins, buttons, legos, rubber bands, plastic balls, cork, and grapes. You will want to have a varied selection of objects and not all out of the same group (i.e.- you don't want all metal objects).

Procedure: After gathering the objects, ask the students what level they think each object will stop in. Then drop one object at a time into the jar and observe where the object stops. Record your results and compare them to what the students hypothesized.

Results:

-If you were to use some metal objects, a button, a grape, a rubber band, a plastic object, and a cork, these are the results you will most likely receive. Results will vary due to the objects that are used.

1. Metal objects have a heavier density than syrup so they will settle at the bottom of the jar.
2. The button and the grape settled on top of the syrup because they are denser than water, but less dense than syrup.
3. The rubber band and most plastic objects settle on top of the water because they are denser than oil, but less dense than water.
4. The cork is the least dense, so it settles on top.

 

Misc. Helpful Information/ Hints/ Suggestions:

The liquids will settle with the syrup on the bottom, followed by the water, and then the vegetable oil on the top because maple syrup is the densest, water next, and vegetable oil is the least dense. The object's density is related to how dense they are compared to the liquids. Remember that the weight of and object does not matter. This is why a very light weight paperclip will fall to the bottom of the jar, while the heavier grape will settle on top of the syrup.