57 



water, the spoon or straw looks as though it were bent at the 

 point where it enters the water. If we put a coin in an 

 empty basin and move the basin so that the rim just hides 

 the coin from view, and then fill the basin with water, the 

 coin can be seen again. 

 These results are due to 

 the fact that rays of light 

 coming from the water 

 are bent in such a way 

 that they seem to come 

 from points nearer the 

 surface. This bending 

 of the rays of light when 

 they pass from one me- 

 dium to another, is called 

 Refraction. 



Put a coin in the bot- 

 tom of a high beaker FIG. 43. The coin looks nearer the top than 

 . . * it really is. 



containing water, and 



holding a ruler against the side of the beaker, adjust the 

 ruler until its lower end seems to be at the same level as the 

 coin. Then measure the distance from the end of the ruler 

 to the surface of the water ; this distance is the apparent 

 depth of the coin below the surface. Measure the distance 

 between the real position of the coin and the surface of the 

 water. This distance is the real depth of the coin below 

 the surface. 



How does the apparent depth of the coin compare with 

 the real depth P 



