COMPARISON OF THE BODY WITH AN ENGINE 91 



2. Prepare an exhibit to show what you have done. You might 

 show: 



(1) Potatoes equal in weight to those used. 



(2) The starch you obtained. 



(3) The residue. 



(4) A chart comparing your results with the actual amount 

 of starch in potatoes as learned from food tables. 



(5) A written report of your work and results including an 

 account of starch factories, possibly illustrated with pictures. 



Project III. To PLAN FOR ECONOMICAL BUYING FOR OUR FAMILY 



FOR ONE WEEK. 



1. Determine foods and amounts of each. 



2. Determine proportion of different nutrients needed. 



3. Compare costs. 



4. Purchase cheaper foods giving required nutrients. 



5. Make a written report comparing your purchases with those 

 of the previous week. Give your conclusions before the class. 



Comparison of the human body with an engine. We 

 have already compared the human body to an engine. Let 

 us go farther with this comparison. It is like an engine in 

 that it contains very many complex parts, each of which 

 has some particular work to do ; for example, the fire box, 

 or steam chest of the engine, or the carburetor of a gaso- 

 line engine, or in the case of the human body, there are 

 the lungs and passages leading to them, the food tube 

 with its different complex parts, and the system of blood 

 tubes and the blood within. We find, moreover, that an 

 engine and the human body both work more or less auto- 

 matically, although the locomotive is controlled from the 

 outside, while in the body control comes from within. 

 Both engine and body need fuel in order to do work. In 

 order to release the energy locked up in the fuel, we must 

 have oxygen to unite with it. Both engine and body must 



