i* JUNIOR GRADE SCIENCE 



The class results should be collected, tabulated, and from them the 

 number of square centimetres in a square inch can be found. 



Measurement of area. By the term area is meant the amount of 

 surface which the thing referred to has. For the purpose of expressing 

 this it is necessary to have a unit or standard. In the English system 

 the unit of area is taken from the corresponding unit of length. For 

 example, the length of this page would be stated in inches, while the 

 length of Ireland would be stated in miles. The area of this page 

 would be stated in square inches ; that is, the number of squares of one 

 inch side into which it could be divided. In the same way, in the metric 

 system the unit would be the square centimetre. By measuring a 

 number of square figures, in both square centimetres and square inches, 

 and dividing the latter measurement into the former, the relation 

 between these units of area can be obtained. Careful work shows 

 that one square inch is equal to 6-451 square centimetres. 



5. AREA OF RECTANGLES. 



i. Area of a rectangle. On the squared paper draw a rectangle of any 

 convenient size. Find the area of it by counting the number of units of 

 area enclosed in the figure. Also count the number of units of length in 

 two adjacent sides. 



Different members of the class should select rectangles varying in size 

 and shape. The results should then be collected and tabulated. 



Area of rectangles. When a rectangular figure is drawn on squared 

 paper its area can be found by counting the number of units of area 

 inside its boundaries. The most convenient way to do this is to count 

 the number of units of area in one row, and then multiply by the 

 number of rows of units in the figure. 



