30 .1 UNIT IN 



and observe whether there is a change in color. Feel the soil. Is it 

 smooth, sticky, <>r gritty? Do you find small pieces of rock in it? 

 Examine closely with the hand glass and describe fully all that you 

 see. Try to find out what the hard particles are. If they will scratch 

 ut;i>>. \\e may be quite sure that they arc some form of quartz. Put 

 sonic of the soil in a large test tube, cover with water, shake thorough- 

 ly and set aside for a few minutes. Which part of the soil goes to the 

 bottom of the tube? Which next? Make a drawing of the soil in the 

 tube. By digging a few holes in the home garden or field, try to find 

 out whether the arrangement of the soil particles is the same as 

 in the tube. Examine the soil along a stream to see whether you 

 can find illustrations of sorting soil by water. Pour off the water 

 from the soil in the tube, and evaporate to dryness. Is there any- 

 thing left? What do you suppose it is? What does this prove? 

 Examine the inside of a tea kettle for a scale of covering. How did 

 it get there? Its presence there proves what? 



Ex. 14. Study of Soil (continued). 



Material : a handful of soil from the school yard. Carefully weigh 

 a small handful of the soil. Now dry thoroughly, being careful not 

 to burn any part of it, and weigh it again. Account for any difference 

 in weight. The loss in weight is what per cent of the weight before 

 drying? Now place the dry soil in a sand crucible or iron pan and 

 heat hot. Cool, weigh, and examine carefully. Account for any 

 loss in weight. Do you believe that you could burn all of the soil ? 

 Do you notice any difference in color after burning? Do you know 

 what it was that burned? 



Ex. 15. Study of Soil (continued). 



Repeat Exercise 14, using the richest black soil you can get from 

 the home garden. Compare the results with those obtained in Exer- 

 cise 1 I. Compare results with those obtained by one of your class- 

 mates who used the same soil. Is there substantial agreement? Try 

 to account for any difference. 



