Activity: Impact Study of Falling Objects
revised 2.18.03

 Note: what follows is a suggested game plan for doing the Impact studies in your classroom. Please be sure that you can do these activities with your students within the collaboration timeline (February 3th - March 7th) and submit your experimental data no later than February 28th. If this is a problem please contact me at icharisc@stevens-tech.edu.

Overview

 Objects that hurtle through space and land on the earth can cause serious damage. But when do you start worrying about the size factor? In the movie Armageddon the size of the asteroid was the size of Texas. But how big does an object have to be in order to be a significant threat to earth? What about the composition of the object? How does that effect what happens? You will answer these and other questions by doing an experiement where you will take 5  objects and drop them from different heights. You will then  measure the impact the objects make.  Based on your results you will make conjectures about what roles mass, weight, density, velocity, and acceleration play in determining outcome. After the data is submitted and compared with data from other participating schools, you will summarize your findings and share them with the other schools.

Objectives

Students will learn:

• The relationship between falling objects and their impact
• The effects that differences in mass, size, velocity, angle of attack and impact area will have on the impact crater and surrounding area.
Materials

• A pan consisting of layers of beach sand, kitty litter and flour. For alternatives and recipes click here.
• Five objects of various size, weight and composition to act as simulated meteors.
• A device for dropping objects. (Example in photo above is an 8 ft. long (1x4) board with a simple tray & release mechanism). The easiest method is to drop objects by hand. However, the height of the drop must be measured carefully.
• A balance for measuring the mass and weight of the objects.
• A ruler for measuring simulated meteor & impact crater dimensions as well as ejecta.
• A sling shot for accelerating a simulated meteor (optional)
Time frame

Three periods: (1) Prepare the students for the experiment, (2) do the activity, and (3) discuss results.

Procedures

• Teacher "sets the stage" for the activity by explaining to the students the details of the experiment they are about to do.
• Students working in groups drop their objects one at a time from different heights.
• Record the length, width, depth and distance of ejecta from the crater rim for each simulated meteor and enter on a recording sheet. (You can use the one provided (recording sheet) or make up your own.)
• Repeat the procedure at height increments of 30 centimeters (up to 180 cm).
• Debrief the results. Each group explains in written and oral form the results of their experiments .
Extensions

As a grand finale for your students, demonstrate a more forceful impact using a slingshot. What happens if you change the angle of impact? How could you test this? Try it!

Recipes for the surface

The following materials work well as a base for your dropped objects (topped with a dusting of dry tempera paint or other material in contrasting color): all purpose flour, baking soda, corn meal, sand & corn starch (mixed 1:1). Pans should be plastic, aluminum or cardboard. Do not use glass. They should be at least 7.5 cm deep. Basic 10x12 pans work fine, but the larger the better.

Anyone want to share a recipie that you found to be successful? (click here)