Day 21

1. Day 21 Make shale and take Quiz 3

2. Compare • Compare your two sandstone samples and your shale sample. • How are the alike? • Both composed of particles • Both sedimentary rock • How are they different? • Sandstone is rough • Shale is smooth, made with smaller particles

3. Stream Table • The sediments from the stream table are smooth. • It is composed of clay, silt or both • Silt and clay were carried much farther in our stream table than the sand, because they are so small.

4. Particle size • How did the clay and silt get so small? • A rock would have to get smashed around a great deal to get that small. They must have traveled and or weathered a great deal. • Where do we find silt and clay in nature? Near or far from the source? • Far • What size particles would you find in slow moving or still water? • Small

5. Shale • What size particles should we use for shale? • Silt or clay • What happens to wet clay of it dries out? • It hardens • Water can be removed 2 ways • It dries out when water retreats • It gets squeezed out due to compaction

6. Shale • Sandstone is a mixture of sand and a matrix such as silica. • Shale has small particles like silt and clay and the water has been removed. • Normally shale forms when the clay dries out and hardens and does not require a matrix. • We do not have millions of years to wait, so we are adding plaster of paris to our mixture. • We find shale in places where there is slow moving water like edges of rivers, swamps, lakes and ponds.

7. Recipe • 3 heaping spoons of clay • 2 heaping spoons of plaster of paris • 30 mL of water • Mix clay and plaster • Add water. It should be thick like cookie dough. Add more water if needed. Don’t add too much! • Spoon on top of sandstone. • Clean cup and spoon as you did with the sandstone.