## 08 Jan Washer and Candy Lab

**Washer and Candy lab **

**Can you guess the number of each?**

**Teacher Notes**

Materials Needed: Bags or cups, enough for 1 per group of students. Two objects such as nuts, bolts, washers, candy, etc or 16d and 8d nails (they need to be uniform size), etc. A scale that weighs in grams.

Procedure:

- The teacher will weigh one washer and one candy in grams (if needed do more than one and find an average).Give this information to the students.
- Have each group place a random number of washer and candy in a cup.They need to secretly record the number of each, as well as the total number of objects in the bag/cup. Record the total number of objects on the bag/cup.
- Each pair of groups will exchange cups.The receiving group can only weigh their new cup. They cannot count them. If you prefer, as teacher you can have cups/bags already prepared instead of the groups doing it. This saves class time.
- You can use a system of equations to solve.Your mathematical solution may not result in
**whole numbers**since there may be a slight variance in manufacturing of nuts and bolts. You will need to adjust. - Give a prize to those groups that can determine the number of nuts and number of bolts in their cup.

Sample:

washer (n)

candy (b)

washer weigh 20 grams

candy weigh 45 grams

Total weigh of cup of items 1990 grams

There are 72 objects in the cup

n + b = 72

20n + 45b = 1990

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