Earth Study 821 



7. Make the following experiment to show what the brook is carrying 

 after a storm when the water is roily. Dip from the swift portion of the 

 stream a glass fruit jar full of water. Place it on a window-sill and do not 

 disturb it until the water is clear. How much sediment has settled at the 

 bottom of the jar? Where was this sediment when you dipped up the 

 water? If this quart of water could carry so much soil or sediment, how 

 much, do you think, would the whole brook carry? 



8. Where did the brook get the soil to make the water roily? Study 

 its banks in order to answer this question. Do you think the soil in the 

 water came from the banks that are covered by vegetation or from those 

 which are bare? 



9. How did the brook pick up the soil that it carried when it was 

 flooded? Do you think that one of the tools that the brook digs with is 

 the current ? Try to find a place where the swift current strikes the bank, 

 and note if the latter is being worn away. 



10. Does the swift current take more soil where it is flowing straight, 

 or where there are sharp bends ? How are the bends in the brook or creek 

 made? 



1 1 . Thrust your bare hend or arm into the swift current of the brook 

 when it is flooded. Do you feel the gravel strike against your arm or hand? 

 Wade in the water. Do you feel the pebbles strike against the feet or legs, 

 as they are being rolled along the bed of the stream? 



12. Does the water, loaded with soil and pebbles, dig into the banks 

 more vigorously than just the water alone could do ? Which washes away 

 more earth and carries it down stream — a fast or a slow current ? 



13. Does the water of the brook flow fastest when its waters are low or 

 high? When the brook is at its highest flood, do you think it is working 

 the hardest? If so, explain why? When it is working the hardest and 

 carrying most soil and gravel, does it make a different sound than when it is 

 flowing slowly and its waters are clear? 



14. How does the brook look when it is doing the least amount of work 

 possible ? 



15 Make a map of your brook showing every pool, indicating the 

 places where the current is swiftest and showing the bends in its course. 

 To test the rapidity of the current, put something afloat on it and measure 

 how far it will go in a minute. 



16. How many kinds of trees, bushes and plants grow along the banks 

 of your brook ? How many kinds of fish and insects do you find living in it ? 

 How many kinds of birds do you see frequently near it ? 



A brook f lizzie jar pupils to solve — When we have a load to carry we go 

 slowly because we are obliged to; and the heavier the load, the slower we 

 go. On the other hand, when we wish to run very swiftly we drop the load 

 so as not to be weighted down; when college or high school boys run races 

 in athletic games, they do not wear even their ordinary clothing, but dress 

 as lightly as possible in trunks and tights; they also train severely so that 

 they do not have to carry any more flesh on their bones than is necessary. 

 How is it that in the case of a brook just opposite is true? The faster the 

 brook runs, the more it can carry; and the heavier it becomes the faster it 

 runs; and the faster it runs the more work it can do. 



