44 
UNIVERSITY OF CALIFORNIA-EXPERIMENT STATION 
practical helps. Write to College of Agriculture and TJ. S. Depart¬ 
ment of Agriculture for bulletins. Above all else, set the children to 
watching these animals to discover their manner of life. 
4. Physical Phenomena and the Inorganic World 
Weather .—Work of the weather bureau of the U. S. Department 
of Agriculture in relation to farm interests. Weather maps. Get 
copies for several succesive days and with a wall map of the United 
States learn how to read the weather map. Meanings of areas of high 
pressure and low pressure. What do the arrows on the map indicate? 
Meaning of isobars. The movement of a storm. Character of clouds, 
winds, and changes of the barometer and thermometer. 
Barometer .—Study in connection with weather map, etc. How is 
a barometer made? Use of mercury. How high is the column of 
mercury at the sea level? What is the pressure of air at this point? 
How is the barometer useful in measuring the heights of mountains, 
etc. Actions of the barometer to indicate fair or foul weather. 
Review the thermometer. 
Light .—Meaning of the term ‘ ‘ self-luminous. ’ ’ Give illustrations 
of self-luminous bodies in nature. What is a “ luminous’’ object? 
Give illustrations. How do light-rays travel ? Which travels the faster, 
light or sound ? Give proof of your answer. What is the velocity of 
light per second ? Of sound ? How long does it take light from the 
sun to reach the earth ? How long does it take to reach the earth from 
the nearest fixed star ? Why does a spoon appear broken when placed 
in a tumbler half-full of water? Why can we see ourselves in a 
