Betsy's Worth

Finally, we think about the story again. John Hull put Betsy on the balance and poured out coins on the other side until the scale was even.  How much was Betsy worth?  How could we determine this?

Materials Required

• Clothes Hanger

• String

• Plastic containers (cottage cheese or similar)

• Action figure

• Pennies

Procedure

1. Make a balance scale by tying string to a hanger

2. Punch three holes in two plastic containers.

3. Tie three strings to each container as shown:

4. Attach the strings to make a balance. You may need to move a string on the hanger so the balance will be even.

5. Place your action figure in one cup

6. Add pennies to the other cup

7.  Add pennies until the balance is even.

8. Record the number of pennies required to balance the scale.

Question:  How many coins do you think were necessary to balance Betsy?  

A simple ratio could help answer our question:

Number of Coins               Number of Coins

--------------------     =        --------------------

Action Figure                           Betsy

Betsy is about 8000 times larger than our action figure.*

        20 coins                          Unknown Coins

   -----------------   =            --------------------

  Action Figure                     Betsy (Action Figure X 8000)

To solve the ratio we cross multiply:

20 coins X Betsy (8000) = Action Figure (1) X unknown

Using a little algebra,

X unknown = 16,000 coins

Question: Can you imagine a pile of 16,000 coins?

*If you are interested in more details of how to think about how to solve this problem, Click here:   Calculating Betsy's worth.