Counting by Weighing

1. Obtain a sandwich bag from your teacher. Your bag may contain items such as rice, beans, or paper clips.

2. Your challenge is to determine the number of objects in your bag without opening it.

3. Brainstorm how you will solve the challenge with the members of your group and decide what tools you might use.

1. Describe the method you are going to use to determine the number of objects you have in your bag. Be specific.

2. Find out what substances are in the sandwich bags of the other groups. Make a list of all the substances.

3. Which of the substances will be easiest to count? Explain your reasoning.

4. Making Sense What do you think this activity has to do with keeping track of chemical compounds?

5. If You Finish Early Are 100 molecules of snake venom equivalent in toxicity to 100 atoms of arsenic? Why or why not?

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