Sedimentary rocks form thanks to the process of erosion. Wind, water, and ice slowly break apart all types of rocks turning it back into soil, or sediment. As the soil is being deposited from the wind and water on the ground, layers are formed called strata. The sediment builds up and the weight and pressure causes the particles to start sticking or cementing together to make sedimentary rocks. These rocks have layers in them from the sediment that made them. The layers at the bottom are older than the layers at the top because they were deposited first.
Supplies you will need:
- 8 oz. plastic bottle with cap
- Playground sand
- Food Coloring (assorted colors)
- Plastic container with lid (to mix colors)
- Funnel
- Plastic spoon
Instead of purchasing pre-colored sand, you can actually make it at home by following these simple steps:
- Using a plastic container with lid, add 1 cup playground sand. Then add 10-12 drops of food coloring. Add more drops of food coloring to create the desired color.
- Secure lid and shake container. Within one or two minutes, the sand particles will absorb and take on the new color.
- Repeat this process for each color desired.
NOTE: You may want to allow the sand one day to dry otherwise you may find the colors will blend and turn brown once layered within your bottle.
The bottle is going to be the outside of the rock that holds the sediment strata within. Use a plastic spoon to scoop the sediment (colored sand) into the funnel that is placed into the top of the bottle. Using one color at a time, you will make different, colorful layers of stratifications.
Be careful not to shake the bottle up once you have started making your layers because all of the colors will start to combine and it will turn your rock brown.
You can also use different materials or types of sand including:
- Pea gravel
- Regular playground sand (without color)
- Black sand (Silica sand)
- Crushed sea shells
- Miniature marbles (only with older children)
- Rock salt