For Teachers
Activity 7A.2 (Lab Activity)
Separating Coins
Note to Teachers: The student version of this activity is a thought experiment that prepares students for a teacher demonstration of the coin separator as described below. Have students perform the thought experiment before the actual demonstration.
Lesson Overview  In this exercise, you will introduce the idea of separation of macroscopic mixtures by demonstrating how a coin sorter separates a mixture of loose change into pennies, nickels, dimes, and quarters. The students must then try to figure out how the coin sorter accomplishes the separation. 
Learning Objectives  Students will speculate as to how the coins are separated. They may guess that the coins are sorted by mass or size. (Both may be used, depending on the make and model of coin sorter you’re using.) Either way, the students by themselves will arrive at the conclusion that separations take place because of differences in size or mass or both. 
Lesson Concepts 

Materials Required 

Skills Required 
Middle school students need to be able to follow instructions and to work cooperatively. 
Time Required 
10–15 minutes, including introduction. 
Safety 
Warn students not to swallow or throw coins. 
Student Ability Level and Grouping 
This activity may be done as a teacher demonstration. (It could also be adapted to be done by middle school students working in pairs.) 
Procedural Notes 

Assessment  See Activity 7A.7, Assessment: A Challenging Separation. 