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Topic: A problem with more than one method of solution
Replies: 2   Last Post: Oct 29, 1995 10:31 AM

 Messages: [ Previous | Next ]
 Rex Boggs Posts: 80 Registered: 12/6/04
A problem with more than one method of solution
Posted: Oct 28, 1995 6:30 PM

"Find the area of skin on your hand. Discuss how accurate you think your

I gave this question to year 10 students some years ago. The number of
different methods the students found was remarkable.

Most modelled the hand as a right prism, and traced around their hand to get
the 'base'. Some then overlaid a centimetre grid and counted squares, while
others divided it into rectangle and triangles and added the separate areas.
Most subtract out the area of the nails.

Getting the area of the 'perpendicular sides' caused a lot of discussion.
Some did it section by section (eg finger by finger), and even modelled the
tips of the fingers as semi-circles to get greater accuracy. Others
carefully laid a piece of string around their hand, and hence found the area
as a single piece.

There were some quite different solutions, however. One girl found a rubber
glove that fitted snugly. She cut it up and laid it flat and found the area
of that. Another painted her hand (!) and noted how much paint she used.
She then painted a rectangle that used the same amount of paint and
determined its area.

The discussions that ensued as to the most accurate method were very
passionate. The kids felt ownership of their solutions. and defended them
strongly.

Cheers

Rex
---

Rex Boggs | High above the hushed crowd,
rex@cq-pan.cqu.edu.au | Rex tried to remain focused.
| Still, he couldn't shake one
Glenmore High School | nagging thought: He was an
Rockhampton, Queensland | old dog and this was a new
Australia | trick - Gary Larson

Date Subject Author
10/28/95 Rex Boggs
10/28/95 Chi-Tien Hsu
10/29/95 Andre TOOM