Earth Science Experiments
One on top of another.
Background
So you thought earth science experiments were difficult? Think again! In this experiment, which you may have seen before, you are going to demonstrate how layers form in soil profiles. (What is a 'soil profile'? Find the answer Good-Science-Fair-Projects.com's
online science dictionary
.) Easy enough, but couple that with
another one of our earth science experiments
and you have a potential whopper of a science fair project. Let's do science...
The Experiment
If something is big and heavy it will sink faster in water than something which is small and light, correct? That is logical. Well, this is exactly what happens with soil particles which find themselves floating around in still (not moving)water. Eventually they are going to settle out, but their size will play a big role in how they do that...The Aim
To determine how differing size of particles result in rock / soil layers. Equipment Needed Various soil types, eg. clay, sand, gravel, loam etc.A fairly large, seal able, transparent, plastic container.A small flexible pipe (you should be able to purchase one made from silicon from most pharmacies).Water. Method In the large container, place equal amounts of the various types of soil that you have collected. Using a stick, or any other appropriate instrument, give the soils a good mix.Add enough water so that the mix of soils is well covered (approximately 4 or 5 cm above the top of the soil).Place the lid on tightly and give the container a good shake.Place the container so that one end is slightly higher, for example by propping one end up on a small rock (this is so the soil will form a slope when it settles out).Leave the container for a couple of days, until all the soil has been deposited.Without moving the container, using the small pipe, siphon off the water.Leave the container for a number of days until the soil dries out. If necessary move it into a sunny spot, but keep it at an angle.NOTE: If you are just interested in seeing the layers of soil as they settle out, this experiment can be done in a glass bottle which need not be left at an angle.
Check out this earth science experiment.
You can use the slope that you have created and to conduct this experiment and see how the different layers affect the “valley” that is formed.Results
The different soil types will settle out, with the bigger particles at the bottom and the smaller ones at the top. The Conclusion
The larger particles sink faster due to gravity while the smaller particles are held up by the water and so settle slower. This will result in layers forming, with the largest particles at the bottom and the smallest at the top of the profile.
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