- Model the effects of weathering and erosion on the land surface.
- Land surfaces are subject to the agents of weathering and erosion. Land surfaces that are not covered with or protected by plants are more likely to be subject to the loss of soil by wind and water
- Weathering is the breaking down of rocks by the earth's atmosphere
- Erosion is the process by which the products of weathering are moved from one place to another.
I will take you through my process of how I prepare before going into the classroom with an exercise like this. In this unit, there are five stations to be set up, however, one of the activities involves using boiling water, not something you can do with second graders. Instead, as the writeup recommends, I might try it as a demonstration. However, before I even use this activity, I will try all of the stations at home with my own kids. There are five activities:
- Chemical erosion in which rock samples are subjected to a weak acid such as lemon juice or vinegar
- First, I have to locate some marble. Usually I will go beg for things in a store, or go through things we have laying around our farm. We do happen to have some marble tiles left over from a project. Another option is to use chalk.
- Other rock samples that don't react with acid are also needed such as granite, gravel, and brick
- Water erosion (this could be very messy!)
- Need a large container of dirt and poker chips and a watering can
- Pour water over a mound of dirt with poker chips embedded in the dirt
- Wind erosion
- Use sand and a small fan to blow the sand
- This seems like a good experiment for the kids to observe and an adult to manage
- Glacier erosion
- Using clay, sand and ice cubes
- Temperature erosion
- Uses boiling water, cold water, and ice to see what happens to glass marble that is subjected to hot temperature and then quenched
- First, I tried the temperature erosion activity. You are supposed to drop a marble in hot water, with the heat source on, leave the marble for five minutes, drop it into water and then into ice. I did this twice and nothing happened. I know that you are supposed to see cracking or splitting, but nothing! I am going to try this exercise in reverse to see if anything happens. I will publish the results. My guess is that the "new" marbles that I have are made differently from the "old fashioned" marbles we are used to seeing. Needless to say, I will not be using this exercise!
- Next, I used a marble tile to show chemical erosion using vinegar. There was no bubbling when I dropped the vinegar onto the marble, as indicated in the write-up stating that there should be. What does happen is less than dramatic. If you leave the vinegar on the marble for a few minutes you get some spotting, but for a group of 2nd graders, this is pretty boring, undramatic stuff. I am still thinking of using something like this exercise, but I may use chalk or pennies, but I still have to think about it.
- For the wind erosion, you are supposed to form a hill of sand in the middle of a tub and using a fan or hair dryer blow the sand around. I did this, and it does blow the sand around, but you also end up with sand particles everywhere! And, isn't that what we all expected? I may skip this one also. I can't really let the kids use a hair dryer by themselves, we would end up with sand absolutely everywhere. I am thinking of seeing if it is possible to do this with straws instead, but I will let you know after my kids and I try it. The drawback to letting the kids use straws is again having sand in other kids' eyes.
Yeah!! This experiment is a keeper and will engage thie kids. Lucky for us, we have outdoor space for these experiments. I will just have to haul in some extra sand, after five classes with four groups each making waves, we could get some pretty mush sand!
This experiment also worked well. I will use it.
Next, I have to figure out what my fourth station will be. I am thinking of getting tubs filled with soil and rocks and having the students water it with watering cans. They can then observe the erosion. In other tubs, I can have soil with grass growing in it, and they can observe that little or no soil washes off that pile. I will do this experiment later today or tomorrow and take photos to post them. In the meantime, I have to produce a write up for all the teachers and the volunteers so they can read background on what the students should learn from each experiment, what questions they should ask the students, and include a data sheet so that students can record their findings like real scientists. I will post these sheets so that you can accesss them if you like.
In the meantime, I have asked some volunteers and teachers to write about their experiences with the program which I hope to post later in the week.