Traffic Jam Activity
Here's the problem, which is also sometimes called Traffic Jam:
There are seven stepping stones and six people. On the three lefthand stones, facing the center, stand three of the people. The other three people stand on the three righthand stones, also facing the center. The center stone is not occupied.The challenge: exchanging places
Everyone must move so that the people originally standing on the righthand stepping stones are on the lefthand stones, and those originally standing on the lefthand stepping stones are on the righthand stones, with the center stone again unoccupied.The rules:
You have tried this activity using two manipulatives (your bodies and the small plastic people). Now try it using the computer. Go to:
- After each move, each person must be standing on a stepping stone.
- If you start on the left, you may only move to the right. If you start on the right, you may only move to the left.
- You may "jump" another person if there is an empty stone on the other side. You may not "jump" more than one person.
- Only one person can move at a time.
(Use the file traffic.mws to experiment with this)
Be sure to manipulate the various options that Mike Morton has made available, including:
Look for a pattern. What do you see? Are there any rules to completing this activity sucessfully? What are they?
- background color
- foreground color
- level of difficulty
- show history and redraw history
There's another version of Traffic Jam at the Math Forum.
- What if there are only 2 people and 3 spaces?
How many moves does it take for the two people to exchange positions?
- What if there are 4 people and 5 spaces?
How many moves does it take for 4 people to exchange positions?
- What about 6?
- What about 8?
- What about 10?
- Can you find a pattern for any number of people?
Please mail comments and suggestions to
last updated on 16 August 1998