Wow! The directions for this project begin by saying, "Prepare two identical dirty cloths." That is easy! I have "prepared" two dirty cloths by spraying them with duster
spray and then dusting the things in the classroom. The cloths have both oil (from the duster spray) and dust in them, and they look yucky.

We have a mixing bowl with a small amount of hard water, and another mixing bowl with the same amount of soft water. Look at the clock, and write down the exact time. We will dissolve a teaspoonful of soap powder in each of the two bowls, and then, start scrubbing on the cloth that is in the soft water. Stop scrubbing, and look at the clock, when the cloth is clean.

Now, let's note the time, and start scrubbing on the cloth that is in the hard water, and when the amount of time has elapsed that it took to get the soft-water cloth clean, we will stop scrubbing. We will hang up both cloths, and check them when they are dry.

Make notes of the differences we notice when we check the dry cloths.

We could bring different soaps and detergents from home, and try them in both kinds of water, to see what the differences are.

Does anybody know the difference between soap and detergent?