EXERCISE No. 55 

 SUN'S HEAT ON DRY AND WET SOILS 



Object: To note the effect the sun has on the tempera- 

 ture of a dry soil and a wet soil. 



Material: Two chalk boxes, dry sand, water, two ther- 

 mometers, and scales. 



Method: Weigh one of the boxes empty. Fill this box 

 with dry sand, and weigh the box and sand together. De- 

 termine the weight of the sand. Add water to the amount 

 of about 15% of the weight of the sand. Fill the second box 

 with sand. Place each box in the sunlight. Put a ther- 

 mometer two inches deep into each box. Take the tem- 

 perature at the start, at the end of ten. minutes, and in twenty 

 minutes later. 



Results : 



Conclusion : Which box was the warmer? 

 Would you consider early evening or early morning the 

 better time for watering plants? Why? 



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