Gravity

Gravity

Unit: Gravity

4^th Grade

Big Idea: Gravity, why things fall down, energy, motion, force, egg drop

Focus Question: How can we move against gravity?

Hypothesis/Prediction:

-       If we use the sponge as a base for the egg with pipe cleaners and yarn around it and wrapped in aluminum foil then it will not crack when we drop it from our knees.

-       If we use the sponge as a base for the egg, then it will not crack when we drop it from our waist.

-       If the egg is surrounded from the top and bottom with sponges then it will not crack when we drop it from our.

-       If we eliminate some of the force using aluminum foil as a parachute, then the egg will not crack when we drop it from our head.

Materials:

-       aluminum foil

-       sponge (cut in small square)

-       straw

-       pipe cleaner

-       yarn

-       cotton balls

-       scissors

-       egg

Planning:

            We first jumped up and down and talked about how high we jump and if we land hard or soft depending on if we just jump up and down or if we jump off a chair. Next we will design 3 carriers using the approved materials listed above. Then, we will conduct at least 3 tests from different heights. From our knees, waist, and head. Then we will collect data for each carrier at the different heights to see which egg survived.

Data:

Carrier Number	Knees	Waist	Head
Prediction 1	Alive	Cracked	Cracked
Prediction 2	Alive	Cracked	Cracked
Prediction 3	Alive	Alive	Cracked
Prediction 4	Cracked	Cracked	Cracked

We think that if the sponge were wet then it would mold, expand, and form to the egg better and therefore would protect the egg more. There were not enough cotton balls for our group. Therefore, we were not able to use them for our experiment.

Claims and Evidence:

            We realized that falling objects are pulled toward the earth by the force of gravity. The longer the object falls, the greater force. To help reduce the force, we lengthened the time of the impact by adding sponges, which was successful if the egg landed on the sponge. However, sometimes it landed on the side, instead on the base (sponge).

Conclusion/Reflection:

            Our predictions were wrong, however, we were on the right track. The egg survived longer if the sponges surrounded it.

            We learned that the egg could have survived if we created a carrier that slowed the egg down, such as a parachute. This would work because a parachute expands during descent and more air is trapped. Therefore, there is more air resistance. We wondered if we dropped an egg, completely covered in sponges, from a building if it would crack?