# Investigation Sequence

## Title

Moon Crater Models autho                 Date

## Focus Questions

How can we experience outer space activity?

## Concepts

### Cross cutting concepts

Interpreting data will allow students to identify trends and patterns.

Models can be used to represent objects.

## Background information

How can we experience outer space activity?

Objectives: Students will measure and record the effects of a crater.  The students will use three different forms of impactors to gather data.  Students will interpret their data and compare and discuss the results.

Vocabulary: Impactors-objects of mass

Lunar- relating to the moon

Crater- depression formed by the impact of an object

Ejecta- ray

Materials: 1pan; “lunar” surface material (potting soil), dry tempera paint, balance, 3 impactors (baseball, golf ball, gum ball), meter stick, ruler, protractor, data chart for each impactor.

## Activity Sequence

Exploration Activity

1.     Fill a pan with surface material to a depth of about 2.5cm.  Smooth the surface, and then tap the pan to make the materials settle evenly.  Sprinkle a fine layer of dry tempera paint evenly and completely over the surface. What does the “lunar” surface look like before testing?

2.      Use the balance to measure the mass of each impactor.  Record the mass on the data chart for this impactor.  Drop impactor #1 from a height of 30cm onto the prepared surface.  Measure the diameter and depth of the resulting crater.  Note the presence of ejecta (rays).  Count the rays, measure and determine the average length of all the rays.  Record measurements and any other observations you have about the appearance of the crater on the data chart.  Make three trials and compute the average values.

3.     Repeat procedure #2 for impactor #1, increasing the drop heights to 60cm, 90cm, and 2 meters.  Complete data chart for this impactor. Note that the higher the drop height, the faster the impactor hits the surface.

4.     Next, repeat steps 2 and 3 for two more impactors.  Use a separate data sheet for each impactor.

Invention Procedure:

1.     Discuss the results

2.     What do the data reveal about the relationship between crater size and velocity of impactor?

3.     What do the data reveal about the relationship between ejecta (ray) length and velocity of impactor?

4.     If the impactor were dropped from 6 meters, would the crater be larger or smaller? Explain your answer.

5.     Compare the results

6.     The size of a crater made during an impact depends not only on the mass and velocity of the impactor, but also on the amount of kinetic energy possessed by the impacting object.  Kinetic energy, energy in motion, is described as: m-mass (x) v-velocity.  During impact, the kintic energy of an asteroid is transferred to the target surface, breaking up rock and moving the particles around. How does the kinetic energy of an impacting object relate to crater diameter?

7.     Looking at the results in your data tables, which is the most important factor controlling the kinetic energy of a projectile, its diameter, its mass, or its velocity? Does this make sense? Explain your answer.

Discovery Procedure: