FOSSILIZED FOOTPRINTS

WHAT YOU NEED

1 large dinosaur model	1 small cup	1 scissors
2 milk cartons	1 stir stick	1 brush water
1 large cup	1 ruler	sand
plaster

BACKGROUND

Long ago a dinosaur walked by a river. He left his footprints in the sandy river bank. Years passed and the river bank was covered with mud. Centuries passed and the mud became rock. Eons passed and a paleontologist made a fantastic discovery: fossilized dinosaur footprints!

You will be recreating this story right on your own desk. Because we don't have eons to wait, we'll use plaster instead of rock. Put any extra plaster in the trash - do NOT pour it down the sink.

WHAT YOU DO

1. First you have to make the "river bank". Carefully cut the bottom off of the milk carton so that you have a box that is about 6 cm deep. Fill it with a layer of sand about 3 cm deep.

2. Now let your dinosaur "walk along the river bank". Make one good footprint in the center of your box.

3. Now we will mix up the "mud". Fill the small cup with plaster. Pour it into the large cup. Now add another small cup of plaster. Add one small cup of water and let the large cup sit until all of the water has been absorbed.

4. Mix the plaster completely and carefully pour it into the box over the sand just as the mud covered the river bank. Be sure you cover the footprint.

5. Now you have to wait - not "eons" but about an hour for the "mud" to turn into "rock". This is a good chance to clean up your work area. Keep your brush - you'll need it later.

6. After an hour (or more), become a paleontologist and carefully lift your fossilized footprint out of the sand. Brush off the loose sand and compare your fossil to the original dinosaur.