Soil Erosion Science Experiment
1 x piece of ply wood (30cm x 30cm x 2cm thick)
6 empty 2 liter bottles
Scissors and Stanley knife
Soil from the garden and compost
4 Seedlings of flowers or grass
Mulch (bark chips, dead leaves and sticks)
Now Follow These Steps:
First: Prepare three of the bottles by cutting a rectangular opening roughly 3 inches x 10 cm along the side of the bottle. Use a permanent market to draw the rectangle before you cut.
Second: Stick the bottle to the wood with wood glue making sure that the necks of the 3 bottles hang a little over the edge of the board. Fill the first bottle with plain garden soil and the other 2 with a soil and compost mixture. Press down firmly to make it nice and compact.
Third: Leave the first bottle alone. Now, cover the top of the soil in the second bottle with your mulch (bark chips, dead leaves and sticks etc). Plant the seedlings in the 3rd bottle. Make sure you plant them tightly together and press down firmly to compact the soil.
Next: Cut the other 3 bottles in half, horizontally and keep the bottom halves (see picture above). Make 2 small holes opposite each other, nearest the cut side of the bottle. Cut 3 pieces of string, roughly 10 inches long and thread each end into the holes. Tie a knot on the ends to secure them. This will form a nice bowl to collect the water. Hang the bowls over the necks of each bottle using the string.
Finally: Make it rain! Slowly pour equal amounts of water in each of the bottles. Pour the water in at the end furthest from the neck of the bottle to simulate rain moving through soil. Observe the color of the water collecting in the bowls. You can add water to the bottles every day and see what happens to the soil over a period of a week. Make observations and find out why plants are important to our environment. Let us know what you see by posting to our Facebook Page or send them to us and we will!
Here’s What’s Happening!
One cause of soil erosion is rain flowing over the soil surface and washing it away. The soil becomes saturated and unable to absorb anymore water. One way to fight soil erosion is to use plants! Plants have root systems that "grab onto" soil and keep it clumped together. Plants also help absorb some of the water in the soil. This in turn makes it harder for the rain water to wash the soil away.
Here's a video to help you build your erosion experiment. https://www.youtube.com/watch?v=im4HVXMGI68
Click to learn more about our Soil Erosion workshop!