Soil Erosion Experiment

This might look like such a simple experiment but it will definitely show the importance of having vegetation covering the soil to your kids! They will love this hands on experiment!

What you’ll need:

  • 6 empty coke bottles
  • 1 x piece of ply wood (30cm x 30cm x 2cm thick)
  • Wood glue
  • Scissors and Stanley knife
  • String
  • Soil from the garden and compost
  • 4 Seedlings
  • Mulch (bark chips, dead leaves and sticks)
  • Water

Step 1

Prepare three of the coke bottles by cutting a rectangular hole roughly 7cm x 25cm along the side of the bottle.

(You can use a permanent marker to mark out the piece you want to cut out.)

Step 2

Stick the bottles to the wood with the wood glue making sure that the necks of the three bottles protrude a little over the edge of the board.

Fill the first bottle with plain garden soil and the other two with a soil and compost mixture. Press down firmly to compact it.

Step 3

Leave the first bottle as is.

Cover the top of the soil in the second bottle with your mulch (bark chips, dead leaves and sticks etc).

Plant your seedlings in the third bottle. Make sure you plant them tightly together and press down firmly to compact the soil.

Step 4

Cut the other three bottles in half, horizontally and keep the bottom halves.

Make two small holes opposite each other, nearest the cut side of the bottle.

Cut three pieces of string, roughly 25cm long and insert each end into the holes. Tie a knot on the ends to secure them. This will form a “bucket” to collect the water.

Hang them over the necks of each of the three bottles on the board.

Soil Erosion

Step 5

Slowly pour equal amounts of water into each of the bottles. Pour the water in at the end furthest from the neck of the bottle.

Take note of the colour of the water collecting in the cups! The water in the first cut is really dirty, the water from the second and third cups are much cleaner which shows that both mulch as well as the root structure of plants assist in preventing soil erosion.

Let the kids do this every day for a week or two and they will soon see how the soil erodes away in the first container while the plants hold the soil in the last one. It’s natures glue, so let’s look after our plants and while we’re about it … plant some more.

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