name(s)__________________________________

date____________

Classroom activity:

What's the Impact?

Purpose:

To investigate the role of kinetic energy (and the factors which influence kinetic energy) in producing landforms and geological structures

Materials:

Fine-grained sand
Flour
Balls of different sizes and/or mass
Tray
Newspaper
Ruler
Measuring stick

Procedure:

Part 1

  1. Lay newspaper down on the working surface. Fill a small tray with fine sand and sprinkle a very thin layer of flour on the surface of the sand.

  2. Drop the marble onto the sand from a height of about ___ cm.

  3. Measure the diameter of the marble. Record the diameter, the height of the drop, and any observations from the drop in the table below.

Part 2

  1. Predict what you expect to happen if you drop the ping-pong ball from the same height. Will the hole be deeper or shallower?


  2. Smooth the surface of the sand (no need for flour).

  3. Drop the ping-pong ball onto the sand from the same height as Part 1.

  4. Measure the diameter of the ping-pong ball. Record the diameter, the height of the drop, and any observations from the drop in the table below.

Part 3

  1. Predict what you expect to happen if you drop the red gumball different heights.


  2. Smooth the sand and drop the gumball onto the sand from the same height as before.

  3. Record the diameter of the gumball, the height of the drop, and any observations from the drop in the table below.

  4. Smooth the sand and drop the gumball from twice the original height.

  5. Record the height of the drop and compare the observations with what you observed in the first gumball drop.

  6. If there is time, drop the gumball at different heights onto the sand, smoothing it before each drop.

  7. Continue to record the different heights of the drops and the differences in your observations.

Material:

Diameter (cm):

Height of Drop (cm):

Observations:

Marble

      

Ping-pong Ball

     

Gumball

      

Gumball

      

 

Questions:

  1. When comparing the impacts on the sand, is size OR mass (weight) of the dropped object more important? Which experiment and observations provided evidence for this?

  2. When comparing the impacts on the sand, does the height from which the object is dropped matter?

Extension - Exploring Scale:

Using a dropper, drip one drop of water at a time onto the surface of the sand. Record or sketch the resulting feature.

Compare these results to photographs of impact craters on Earth, the moon, and Mars.

What are the similarities? Differences?

Background Information and Discussion:

Kinetic energy is the energy of an object in motion and is defined by:
Kinetic energy = ½ (mv2)
m = mass of impacting object
v = velocity of impacting object

In the case of dropped items,
v = 2gh
g = gravity (on Earth this is 980 cm/sec2)
h = height of drop.

Given this information, which should be more significant in controlling the impact: size, mass, or height of drop?

 

Return to: Illustrated Version | Potential to Kinetic | Dynamic Earth Homepage | UCMP Homepege