Overview & Purpose:

To make hula hoops of different circumference and mass and study how these factors affect the speed at which the hula hoop spins around.

Objective:

In this science project, you will create your own hula hoops, spin them, and draw conclusions. The road will then be open to your becoming a hula hoop expert.

Materials Needed:

Polypipe, which is hard, black tubing usually used for irrigation (⅝ inch, ¾ inch, or 1 inch diameter; 100-foot coil). Available from a garden supply store or home improvement store.

Metric tape measure

Calculator

Sharp cutter knife or PVC cutter

Poly insert couplings that fit the size of your tubing (4, same size as your polypipe; for example, ¾-inch poly insert couplings work for the ¾-inch tubing). Wooden dowels with a diameter that just fits inside the tubing with a length of about 1½-inch work as well. Both can be found at a garden supply or home improvement store.

Hairdryer

Wide plastic tape (min. 2.5 cm wide)

Optional: Colorful electrical tape

Funnel with an opening that can fit into the polypipe or 1 sheet of thick paper

Cup measure

Dinner knife with flat edge

Sand (2 cups)

Kitchen scale, such as the Fast Weigh MS-500-BLK Digital Pocket Scale, 500 by 0.1 G, available from Amazon.com.

Bucket

Timer or stopwatch

Helper or person who wants to hula hoop for you

Adult helper

Vocabulary:

Physics

Speed

Force

Torque

Mass

Weight

Gravity

Friction

Decelerate

Diameter

Circumference

Instruction:

1.Consolidate the data by calculating the average number of turns measured over the different sets of data collected.

2.Add the numbers collected across one row (for example, data sets one through four for the big, lightweight hula hoop) and divide by the number of filled columns in that row. For example, if you recorded 60, 80, 65, and 75 as the number of turns for a given hula hoop in one minute, the average would be (60+80+65+75)/4 = 280/4 = 70 for that hula hoop.

3.Write the resulting average in the last column of your data table.

4.Can you see a clear difference in the number of turns recorded for the different hula hoops? Is one clearly faster or slower than the others?

5.Is there a clear pattern (fastest / slowest) in each set of data taken? (For example, does each data set show Hula 1 to be the fastest and Hula 3 to be the slowest?)

6.Is there a link between the characteristics of the hula hoop (e.g. mass, diameter) and the speed at which it turns?

7.If you see a pattern (fastest / slowest), does it match the expectations set before you started the testing?

8.Can you explain why you obtained these results? Hint: If you are having trouble explaining this, try re-reading the Introduction in the Background tab.

9.What forces act on a hula hoop in motion? Which work against hula-hooping and which work in favor?

10.Will a heavier hoop (i.e., one with more mass) rotate slower or faster around your body than a lighter hoop?

11.Will a bigger hoop take less or more time to rotate around your body?

References:

http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p088.shtml#summary