Sedimentation
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DiscussionPre-lesson Questions
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Video LessonsSedimentation
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Experiments and ActivitiesSediment Jar
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Make a Sedimentary Rock
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Sedimentary Rocks Research
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AnswersAnswer Key: Sedimentation
Answer Key: Sedimentation
We encourage you to experiment or do research to find the answers to these questions on your own before looking at our answers!
Sediment Jar
What did your jar look like right after you stopped mixing it?
You may have started to see some particles in the jar floating and some sinking.
What did your jar look like after 10 minutes?
You probably started to see more particles in the jar floating and more sinking.
What did your jar look like after 1 hour?
After an hour, your jar should have had distinct layers.
Can you explain why your jar looked the way it did?
Particles settle according to their density. The heaviest particles that were in the dirt settled to the bottom of the jar, while the lightest particles that were in the dirt settled on top.
Can you make any connections between your jar and a river, lake, or pond?
- Fast flowing rivers shake up water and sediment that they pull from the land. You did the same thing when you added dirt and water to the jar and shook it.
- When rivers slow down or deposit into a lake or pond, the water becomes more still like it did when you stopped shaking your jar.
- All of the different-sized particles that are mixed together in dirt separate when water flows over them. When the water slows down or stops, the heavy particles fall to the very bottom, while the lighter particles end up at the top. This creates layers of different sediment at the bottom of lakes, ponds, rivers, and other bodies of water – especially if they are slow-moving!
Make a Sedimentary Rock
What did the candy look like when it came out of your beaker?
When the candy came out of our beaker, it was all stuck together in one piece with different colored layers.
Which layer of your candy rock is the “oldest”? Which is the “youngest”?
The bottom layer is the oldest. It represents the layer that was deposited the longest time ago. The top layer is the youngest, it represents the layer that was deposited most recently. You learned about this in the sedimentation video!
Find some photos of rocks that look like the candy did when you took it out of the beaker. What kind of rocks are they?
They are most likely sedimentary rocks. You formed your candy rock similar to the way that sedimentary rocks are formed.
The thing you made looks like a rock, but is it really rock?
Your layered candy isn’t really a rock. It is kind of like the condensed layers of sand from the sedimentation lesson. A rock is a solid collection of minerals that grew or got cemented together. Although sugar can form crystals like minerals, it is not a mineral itself. Your candy pieces are also not quite cemented together, although the sticky nature of Jolly Ranchers makes them almost seem like they are.
Talk about how this demonstration relates to sedimentation.
Key points:
- Breaking down the candy represents how water carves through the land, and breaks down rock and earth into tiny pieces of sediment.
- Pouring the candy out of the bag represents how water carries sediment down rivers.
- Layering the candy in the beaker represents how water deposits sediment. The sediment that a river first carried ends up as the bottom layer of a rock. The sediment that a river most recently carried ends up as the top layer of rock.
- The heavy can represents the pressure that is needed to form a sedimentary rock. In real life, this pressure would come from more and more layers of sediment piling up on top.