The year fours have been learning about erosion this term. Part of this has been learning about ways to minimise erosion in our environment. We set up an investigation to look at how some of these suggestions can help reduce the amount of erosion that happens.
Our question for investigation was:
What happens to the amount of erosion that occurs when we change the type of ground covering?
We had three identical 2 litre plastic soft drink bottles, that we cut the side out of and filled with potting mix. One we left bare soil, one we covered with wood chips and in the last we grew wheat grass.
We measured and poured the same amount of water onto each bottle. We put a beaker under the bottles to catch the water that ran out and looked at how much soil was washed into them. We discussed how much soil was present in each beaker of water and what caused some samples to have more erosion than others. Some of our theories were:
- the roots hold the soil in so it doesn’t erode
- the grass disperses the water so it trickles gradually into the soil
- the wood chips also disperse the water throughout the soil gradually, and
- the weight of the wood chips holds the soil in.