Lesson: Weathering and Erosion Lab
This set of experiments was adapted from a series I found through the Illinois Department of Education. I altered it so that it would focus on the differences between chemical and mechanical weathering.
Please read over attahed document, Weathering and Erosion Lab, before proceeding.
To do this lab, you will need to acquire:
1. About ten mason jars or baby food jars- some of the experiments can be done by using clear, plsstic cups, but jars are sturdier if you can get them
2. A liter of carbonated water
3. An ice tray
5. About twenty pennies
6. About ten antacid tablets
7. 4 or 5 pieces of chalk (probably best to chop these into two beforehand)
8. A steel wool (Do not buy the kind that has soap in it. I made this mistake. The kids will not be able to see the oxidation process if the water is a milky mess of blue soap. Take my word for it.)
9. About twenty lumps of sugar
10. Gravel- about one mason jar full
These will do together as a class in order to save time. For this, bring the following:
1. Large saucepan
2. Hair dryer
5. A container for pouring water
On the morning of the day of your experiment, take your ice tray outside and fill it with sand and dirt. Fill it with water and stick it in the freezer (make sure to gross out your colleagues in the process). You will need all day for this to freeze. Fill a mason jar with gravel and small rocks and sand (I went exploring behind the building). Throw about twenty sugar cubes into it. Set it aside. Now, fill a mason jar halfway with water. I showed this to my students before they went to specials at 8:10 and had a student mark the water line. I also stuck this into the faculty freezer.
During my lunch break, I set up all of the different weathering stations in our free room. I am not going to go into detail about how each station was set up- I think that by reading the attached lab you should be able to infer it. Be sure to only have them put in one rock or piece of chalk in at a time- our supply ran out quickly.
Before our experiment (we started around 1:00), remove the jar of water and the ice tray of dirt out of the freezer. I had a student fill the saucepan halfway with sand, having asked them to be careful not to get it on both sides. I divided the class into groups of 4 to 5. Before starting the experiment, we reviewed the differences between mechancial and chemical weathering as a class. (The night before, the students took notes in their science notebooks on the reading in their 'Sciencesaurus' on the differences between the two. It is imperative that they have a good start on grasping the concept before beginning the lab.)
The different groups are each given a different number station to start with. I was lucky to have a parent volunteer to help with supervising stations in addition to our fearless teacher assistant, Mrs. Hamilton. I reommend this if possible. Students move through each station while taking notes on each in their lab packets.
We did the erosion experiments together to save time.
1. Have the students run the ice cubes filled with dirt over a variety of surfaces on the playground: dirt, sand, gravel. What happens? What does this tell us about erosion?
2. Fill a saucepan with sand and use the blow dryer over it to demonstrate the effect of wind on dirt and rocks.
3. Take the saucepan half-filled with sand. Fill the other half with water. Bring each side up and down slowly- imitating the effect of a wave upon a shore. What happens to the sand?
4. Place several ice cubes on a pile of dirt. What happens as the ice starts to melt under the sun? Hopefully, you'll see the dirt moving downward (this one was not terribly illustrative). I.e. how melting ice causes erosion.
Have fun! I had the students complete the labs for homework, and turn them in the next day. Many of them did not answer all the questions in time.