Natural Sciences and Technology Grade 5-B ... - Thunderbolt Kids

3. On the picture, complete the label, Sediment of last year,
2012.
4. On the picture, where must you write Sediment of 2011?
Write it there.
5. On the drawing, next to sediment 5, write I was ... years old
when the river brought this sediment.
Teacher's Note
Sediment 5was deposited in 2008. Let the learners count
backward to 2008 and work out how old they were.
6. In sediment 4, we find the bones of abird. How could abird
get into this sediment? Write or tell a short story about the
bird. Explain why we find its bones under four sediments of
sand. Work out in what year the bird fell into the mud.
Teacher note: For example, "The bird died and fell into the
water. Then it sank in the water and the mud covered it. This
happened five years ago. The next year more sand came
down the river and covered it deeper." If Sophie is standing on
the 2012 sediment, then the bird fell into the 2009 sediment.
We use the example of yearly floods that bring down sand in a
river, because the numbers of years is small. But remind the
learners that erosion and deposition has been going on not
just these few years, but for millions of years. From the time
the first rocks formed from volcanoes on the Earth,
weathering, erosion and deposition began to happen. So we
can find sedimentary rocks that are thousands of millions of
years old.
7. What will you find if you dig deeper than sediment 8?
Rock. The deep layer of rock is called the bedrock.
Look at the picture below of the Grand Canyon –can you see old
sedimentary rock? Look at the sediments of rock. The rock is very
hard now. It has been pressed down for millions of years.
Chapter 3. Sedimentary rocks
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