Yesterday we talked about soil and how soil is made by weathering and erosion.
We broke into groups and each group had a different task to do.
The yellow group used magnifying glasses and tweezers to investigate what exactly was in the soil sample. We found roots, a dead snail, a worm, a stone, and bits of grass.
(This is what it looked like after leaving it to settle all night...the water is much clearer now)The white table and the blue tables had a bit of a competition.
Each table tried to make dirty water (water mixed with soil) clean again.
They did this using filters.
The white group used filters made from stones, sand and cotton wool (in that order, we hoped the stones would catch the biggest pieces of soil, the sand would catch the smaller pieces and the cotton wool would catch all the small pieces that were still left) to filter the water, while the blue group used just a coffee filter to filter the water. We all had a guess before we started as to which filter would work better. Here is what we guessed:
Here is the white group at work:
We felt that this is because the stones we used might have been dirty themselves and so added to the dirt instead of filtering it away, and using sand was a bad idea because it ended up dripping into the bottle along with the dirty water. We decided that if we use filters again we will only use cotton wool. We think that a cotton wool filter might be great for cleaning water.
We learned lots about soil today, and we showed off our new-found knowledge when another 2nd class came to visit us and hear about our findings.