28 ENVIRONMENT OF PLANTS AND ANIMALS 



Problem 5 : To determine and to illustrate by a graph the 

 changes of temperature {one of the factors of tlie environment) 

 during a given day. 



Materials. — Thermometer, clock, graph paper. 



Method and Observations. — Take the temperature (outside) 

 at 7 a.m. and at each successive hour during the day until 6 p.m. 

 On a piece of graph paper lay off a line parallel to the bottom 

 of the page. On this line, at equal distances, place your hours, 

 beginning at 7 and ending at 6. Then from the line made as a 

 base, erect perpendiculars on each of the hour marks. On these 

 perpendiculars mark the record of the thermometer at the given 

 hour. Begin your record at the base line, e.g., if the thermometer 



