Science experiment: pumpkins

I got this experiment idea from our charter school email list. It was perfect--easy, low maintenance, few supplies, and not too long.

 Learning About Density and forming a hypothesis

Before the experiment: Use your science book, dictionary, or the Internet to answer the following questions.
1. What is density?
2. What is weight?
3. What is a hypothesis?
4. Why do things float or sink in water?

 Objective: In this activity, students will learn about density and forming a hypothesis.

Materials for Activity:
Measuring tape
Bathroom scale
Bathtub
Water
Pumpkins of various sizes (at least 3)

Procedure:
1. Make predictions (hypothesize) of the circumference and weight and record on the data sheet. Use the measuring tape and scale to measure the circumference and weight of each of the three pumpkins and record results.
2. Based on the information you’ve gathered so far, make a prediction about whether the pumpkins will float or sink, and record the hypothesis on the data sheet.
3. Place each pumpkin in water and record results.
4. Hypothesize whether additional items (like rocks) will sink or float. Place the additional items in the water and record results.

Data (make a chart with a column for each of these areas):
Item
Hypothesis of Circumference
Actual Circumference
Hypothesis of Weight
Actual Weight
Hypothesis: Float or not
Results

Results: 
1. Were your hypotheses correct or not? ______________________________________________________
2. What did you learn about the density of pumpkins? ______________________________________________________
3. Where were the stems of the pumpkins when they were in the water? ______________________________________________________
4. Did the size of the pumpkins affect this? ______________________________________________________
5. What did you notice between the buoyancy of pumpkins and other fruits and vegetables? What is your reasoning? ______________________________________________________