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How Craters Form
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Science Process Skills
- observing
- measuring
- organizing
- comparing
- applying
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Math Skills
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Materials
- Metal cake pan
- All-purpose flour
- Ground coffee or ground pepper (any similar substance that will stand
out when sprinkled on the surface such as gelatin, cocoa, or tempera
paint powder)
- Several different sized and shaped objects (B.B., marble, small washer,
bolt or screw, and sugar cube.
- Ruler
- Garbage bag
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Doing the activity
- Prepare for the activity by placing the garbage bag on the floor.
- Predict the shape and size of the craters that will be formed after
dropping each object into the powder.
- Fill the cake pan half full with the flour and place it in the center
of the garbage bag.
- Sprinkle some of the coffee or pepper over the surface (only use part
of the mix, saving some for each trial).
- Drop an object you have from a one-foot height. Keeping the height
at 1 foot controls this variable so craters formed by different objects
can be compared.
- Measure the width and depth of the crater.
- Observe and draw the crater formed by each object.
- Repeat for the other objects.
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Talking it over
- What shape was the crater?
- How did the object affect the surface of the powder and flour?
- How did the size of the object affect the size and shape of the crater?
- How did shape of the object affect the size and shape of the crater?
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- Applying
- How does your crater work in the experiment compare with the splashes
made by people jumping into swimming?
- Why do the craters form the way they do?
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- What's Happening
- Craters form when an object strikes the surface of a planet, moon,
or other space object. Craters are found here on earth as well as the
moon and most other planets. The energy from the impact of an object
such as a meteorite is transferred to the surface that it strikes. The
energy from the impact forces the surface it strikes to move. Material
from the surface is thrown from the impact area to form a ring of material
called ejecta. The crater can contain rocks that were changed from the
impact. These rocks can be broken or melted. The crater will be circular
in shape. It will be about 10 times larger than the diameter of the
object that forms it and 1/10 as deep as it is wide. The crater can
change depending on the size, mass, and speed of the object. The angle
that the object strikes the surface will also be a factor.
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More Challenges
- Use a telescope or binoculars and observe the moon's surface. Why
are the craters so visible on the moon?
- Research some famous craters and compare them to the craters you made.
- Try the experiment again from a greater height. How does this affect
the craters that are formed?
- Try the experiment again by throwing the object into the pan form
an angle. How does this affect the craters that are formed?
- Calculate the energy that an object has when it strikes the surface
using the formula K.E.=mgh. K.E. is kinetic energy, m is mass, and h
is the height the object is dropped from. Measure the height in centimeters,
mass in grams, and gravity is 980 cm/s2 (s=seconds). Your answer will
be measured in ergs (an erg is g x cm2/s2).
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Related Web Sites for Students
Terrestrial Impact Craters http://www.solarviews.com/eng/tercrate.htm
Venusian Impact Craters http://www.solarviews.com/eng/vencrate.htm
Terrestrial Impact Craters Slide Set http://www.lpi.usra.edu/pub/publications/slidesets/craters.html
Related Web Sites for Educators
Meteorite Mysteries
http://spacelink.nasa.gov/Instructional.Materials/NASA.
Educational.Products/Exploring.Meteorite.Mysteries/
Exploring.Meteorite.Mysteries.pdf (large file)
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ISU Extension 
