Re: Tired Weight

From: On-line Snack discussion (
Date: Tue Jul 27 2004 - 15:51:53 PDT

Dear Bob,
Below is your answer from the creator of the Tired Weight Snack.
Hi Bob,
When we do this activity, we usually get the weight within 5 to 10%. On
rare occasions we might be off by as much as 20%. Something is wrong if
you are getting 100% error.

Here are things to check in your experiment:
-The weight of the car is inside the driver's side door. You need to get
the gross vehicle weight or add the front and rear axle weights together
(This has been a common error before - People only using one axle's weight
will get about half the weight of the car.)
-You really need to jam the cardboard under the tires to get the correct
surface area of the tires.
-You need the surface area and pressure from each tire separately.
Calculate the weight for each tire, then add the weights to find the total
for the car.

Hope this helps.

-Eric Muller
Science Educator
Deb Hunt
Snacktalk Moderator
3601 Lyon Street
San Francisco, CA 94123-1099

On Wed, 21 Jul 2004 wrote:

> Help! Please!
> While attending a workshop for teachers, we tried this activity on two
> different cars...However, in each case we calculated the weight of the car to be
> roughly double the car's actual weight. How could this be? What might we have
> done incorrectly?
> Bob Kohut

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