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

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

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

3. Jar Activity • Before Shaking/Mixing What do you observe? • After Shaking/ Mixing What do you observe?

4. Sorting in General • Density affects the sorting of naturally occurring materials in a mixture. • For example, dense objects like heavy and large rocks stay at the bottom while less dense objects like light and small silt and dirt can be carried away by the flow.  

5. What is density? • Density = Mass/Volume • Mass = The amount of matter in something. • Volume = The amount of space occupied by something. It is the size of something.

6. How does density affect sorting? • Knowing that some things float on while others sink gives us a good idea about how density relates to things around you. Not only does density determine when something will sink, it also is responsible for the different layers of the Earth and the sorting of natural materials on the Earth!

7. 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 =.0013 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

8. 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? • Have you ever heard the saying “the bigger they are the harder they fall”? In streams/rivers this is often true. The larger items have more matter in them. Robert Wadlow (1918-1940) holds the record for the world's tallest person at 8 feet 11.1 inches tall. The tallest living person is Sultan Kosen of Turkey, at 8 feet 1 inch tall.

9. 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 that could be found on the exterior of 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 1st ... from bottom to top. Is this a case of “The bigger they are the harder they fall?

10. How will Earth materials with different densities but equal sizes sort? Do you remember our 4 – Color Column Demonstration? Will Earth materials do the same when mixed up? Clear Air (gas) 0.0013g/cm3 Density Yellow Fluid 0.93g/cm3 Density Green Fluid 1.01g/cm3 Density Red Fluid 1.38g/cm3 Density

11. Imagine if ….. Sand Origins 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?

12. Sorting according to density in Nature • Can you think of any examples of sorting by density and/or size in nature? • Beaches • Streams • Road Cut

13. 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? Sorting: The Beach

14. 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? Sorting: Stream or River

15. Action of Streams Tubing Story

16. Sorting Evidence in Road Cuts? Slightly different story. http://www.mgs.md.gov/esic/brochures/sideling.html (Best Road Cut)

21. Quiz • 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

22. Quiz • 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

23. Quiz • 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

24. Quiz • 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

25. Quiz 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

26. Quiz 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

27. Quiz 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.

28. Quiz 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 rapidly. b. Silt is small with low density. • Water has a high density

34. Sorting