8 



Our Surroundings 



one another and that it is this attracting force that drew the 

 apple to the earth and that holds the great planets in their courses 

 around the sun. More experiments and a further study of ob- 

 served facts have since made this theory a generally accepted law, 

 known as the law of gravitation. 



Importance of the Experiment. An experiment is an at- 

 tempt to find out by observa- 

 tion something that we do not 

 know. For example, a physi- 

 cian feeds different kinds of 

 food to rats in order to learn 

 which of these foods are most 

 nourishing. A farmer, who 

 has lost his wheat crop on sev- 

 eral occasions because of 

 frosts, experiments with dif- 

 ferent kinds of wheat and 

 tries to develop a new variety 

 that will better endure the 

 cold. The experiments with 

 the rats and with the wheat 

 are efforts to discover some- 

 thing unknown that, if known, 

 would help man to make more 

 of his surroundings. In the 

 same way, most great truths 

 have been discovered by long- 

 continued and repeated experiments. Experiments are the very 

 basis of the scientific method. 



Here is a very simple example of the experimental method. 

 Alice sees cans of milk being weighed at a milk station, and 

 wonders whether these cans would weigh more or less if they 

 were filled with water. Her curiosity is aroused and she decides 

 to find the answer for herself. She uses the kitchen scales and 

 two quart bottles. She weighs the bottles when empty, then fills 

 one with milk and the other with water and weighs them again. 

 She compares the records of the weighings and so reaches the 



E. S. Houck. 



COMPARING THE WEIGHTS OF WATER 

 AND MILK 



