Geology+Learning+Experience+13

Learning Experience 13: Soil ingredients, Large and Small
Materials:
 * small cups with 2 pebbles and a few pieces of gravel
 * drawing paper to tape the rocks to
 * pens to label with
 * paper plates with some clay on them and with some sand on them (one of each for each per pair)
 * magnifying glasses
 * tape
 * sieves, in 3 sizes
 * newspaper
 * science notebook page: [|sieving science notebook.doc]

LT:
 * I can explain how rocks get smaller and smoother.
 * I can list soil ingredients and explain where they come from.
 * I can sieve soil ingredients to find out which are smaller and which are larger.


 * 1) Look at learning targets: Last week we were talking about how rocks get smaller and smoother. What do you remember about some things that make rocks get smaller and smoother? (Chart ideas) Where do rocks come from? Add ideas about this to chart.
 * 2) Last week you put some rocks in order from largest to smallest. Today we are going to tape down the rocks you used last week, into a "Rock Continuum," and label them. A "Rock Continuum" is a line of rocks from large to small. Then we are going to do an experiment so we can add some tiny, tiny, tiny particles to your rock continuum.
 * 3) Have students work in pairs with the following: 2 pebbles and a few pieces of gravel. They tape them down in order with scotch tape and label them. You will have to define that a pebble is bigger than gravel.
 * 4) Introduce the plates with sand. Have students look at it carefully with magnifying glasses or hand lenses. Ask; Do you think sand comes from rocks?
 * 5) Then introduce dry clay. Have students look at it with hand lenses and share a few properties of it. Ask if they think it comes from rocks. Ask them to explain their reasoning.
 * 6) Tell them that today they need to find out which is larger and which is smaller, so they can add the clay and the sand to their Rock Continuums. Demonstrate how to sieve them.
 * 7) Introduce the 3 kinds of screen: window screening, quarter-inch screening, and half-inch screening. “Geologists use screens as sieves to study soil.” Explain “sieve” = a tool used for sifting, or “to sift.”
 * 8) What do you think geologists might find out about soil from sieving it?
 * 9) Hold up the half-inch screening. What would get caught on this screen? Big soil ingredients or small one?
 * 10) What about the quarter-inch screening?
 * 11) What would get caught on the window screening? Big soil ingredients or small ones?
 * 12) Demonstrate how to use the screens with some potting soil. Pile the screens on top of each other. Show them how to move the screens side to side, not up and down.
 * 13) What do you notice about what happened?
 * 14) Record the results on a large version of the recording sheet so they can see how to use it...?
 * 15) Each pair will sieve the clay and the silt to see which is bigger. They will need to decide who is in charge of sieving which ingredient. Teach them to fold the paper plates so they can pour the soil ingredient onto the sieve.
 * 16) Students finish by taping the soil ingredients down: clay is bigger, and silt should be last. They should label them as well.