1. Sorting of Earth Materials: Beaches, Streams and Road Cuts.

2. What is Sorting?
Sorting: To arrange according to class, kind, or size; classify.
Density affects the sorting of natural materials in a mixture.

3. How does density affect sorting?
Below you will find photographs to represent the different layers of the Earth. At the right of each photograph you will find the density for that layer. How would the following materials sort according to density? Order from bottom to top. B A
Density = g/cm3
Density =
Close to 2.7 to 3 g/cm3
Density = 1 g/cm3
Density
4.5 g/cm3 D C
Density = 11.5 – 13.0 g/cm3 E

4. Density
Particles that are more dense sort out first, particles that are less dense sort out slower.

5. Does particle size matter?
Do you think density is the only factor that could influence how natural materials on Earth’s surface sort? What about size?

6. How will Earth materials with an equal composition but a different size sort?
Below are pictures of six different-sized particles of rock that are made of the same basic stuff and are found on the Earth. Imagine that you put them in a large container filled with water and then shake the container vigorously. The particles are labeled A, B, C, D,  E and F. Look closely at each and determine the order you would arrange them in based on how they would settle out ... from bottom to top. Is this a case of “The bigger they are the harder they fall?

7. Particle size
The larger particles settle out faster. The smaller particles settle out slower.

8. How will Earth materials with different densities but equal sizes sort?

9. Imagine if …..
Imagine if you traveled around the world and collected sand samples from different beaches that you visited. The sand grains you collect end up being roughly the same size.
Does this mean that the density of the sand grains will be the same?
How will the sand of different types/densities sort if placed in a jar and shaken up?

10. Examples of Sorting according to density in Nature
Can you think of any examples of sorting by density and/or size in nature?
Beaches
Streams
Road Cuts
Panning for gold

11. Sorting: The Beach
Have you ever walked along a beach and wondered why the sand particles are all in one basic area and the grains are all about the same size?
The denser particles are dropped first right at the shore, and the smaller, less dense particles are deposited further up the beach.
Rocky beaches usually have more violent waves. Sandy beaches usually have calmer waves.

12. Sorting: Stream or River
Try and think of the rocks you have observed in a river or stream. Why do you not see small sized and low density particles like sand and silt being deposited in fast moving water? Why are the big rocks staying in place?

13. Stream or river The big rocks settle out first and stay behind.
The small clay and silt is carried away until the stream slows down

14. Action of Streams
Tubing Story

15. Road cuts: long term sorting
Roadcuts and canyon walls are evidence of sorting because there are different layers that were deposited over a really long time.

17. Panning for Gold
Gold is very dense and settles to the bottom of the pan.

18. Quiz a. rock, sand, water, metal b. metal, rock, sand, water
1. Pat puts items into a jar and shakes it up. Pat lets the jar settle for 5 minutes. What would be the expected order of the items going from the top of the container to the bottom?
a. rock, sand, water, metal
b. metal, rock, sand, water
c. water, sand, rock, metal
d. sand, metal, water, rock

19. Quiz
2.A streambed contains round rocks, all about the same size. Why are there no smaller particles of sand and clay? The sand and clay…
A.  are too small to see  
B.  are denser  
C.  have washed away  
D.  were never there

20. Quiz
3.A beach is composed of particles of sand of the same size. Why doesn't the beach have materials of all sizes? The particles have…
A.  been placed there by humans 
B.  come to the beach at the same time.  
C.  been found in underwater canyons  
D.  been sorted by size and density

21. Quiz
4.Sand with particles of the same size was gently shaken in a jar to see if layers would form. What variable was being tested?
A.  particle size  
B.  particle density  
C.  particle color  
D.  particle type

22. Quiz
5.Where would the smallest particles of rock be deposited in a streambed?
a. Where the water is moving the fastest
b. Where the water is moving the slowest
c. Near the middle
d. At the beginning

23. Quiz
6.In an experiment, students shook jars of water with soil and rock in them. What could the shaking model in nature?
a. A lake environment
b. A stream current
c. Living things in an environment
d. A rainstorm

24. Quiz
7.A student shakes a jar with a mixture of sand types. Instead of mixing, the sand grains separate into layers. Why?
a. The grains are different colors.
b. The grains have different shapes.
c. The grains have different densities.
d. The jar has a round shape.

25. Quiz
8.In the spring, rivers in Utah are cloudy or murky. A sample of the water shows it contains very small particles of silt. Why is silt suspended in the water?
a. The water is moving slowly, and the silt has all settled.
b. Silt is small with low density, and the water is moving too fast to let it settle out.
Water has a high density.