Obtain a large test tube that can be corked. Mix at least three sizes of gravel, some sand, and mud together. Place the mixture in the tube, and fill it with water. Cork and invert the tube.

You will see that as the materials fall through the water, the larger materials settle quickly at the bottom, medium sizes settle in the middle, and fine silt settles slowly at the top.

Rivers, streams, and oceans carry sediments and deposit them on the basis of weight and size.

See what you can find out directly:

If possible, visit a seashore, and collect samples of sand from different locations. The sand can be placed in small vials or bottles and labeled with its location and the date of collection. Upon returning to the classroom, scatter a few grains from each sample onto light green or blue paper. (The color aids viewing of the grains.)

Examine the grains with a hand lens or binocular microscope (if one is available) and identify and classify the differences in types of grains making up each sample.

You might work out the percentage of each kind and hypothesize where the various grains came from. If possible, return to the seashore at later date, and collect samples from the same locations. Compare these samples with the previous ones to see if there are any changes.

This project could probably be adapted to studying river beaches and lake beaches near river inlets, also.