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Common Science 



FIG. 1 88. The white powder that is forming is a silver salt. 



with sugar. You can tell what foods have starch in them 

 by testing them with iodine. If they turn black, blue, or 

 purple instead of brown, you may be sure there is starch in 

 them. And if they do not turn black, blue, or purple, you 

 can be equally sure that they have no starch in them. Some 

 baking powders contain starch to keep them dry. Test the 

 baking powder in the laboratory for starch. Often a little 

 cornstarch is mixed with powdered sugar to keep it from 

 lumping. Test the powdered sugar in the laboratory to see 

 if it contains starch. 



Test the following or any other ten foods to see if any of 

 them are partly made of starch : salt, potatoes, milk, meat, 

 sausage, butter, eggs, rice, oatmeal, cornmeal, onions. 



