Grasp the ruler with your thumb
and forefinger at the end with the
highest measurement and hold it at
head level with your arm extended
away from your body.
2. Ask one of your friends to
be prepared to catch the ruler with
their fingers as you drop the ruler.
3. Have your friend position
their thumb and pointer (slightly
open) at the bottom end of the ruler.
4. Release the ruler and record their results.
5. Write down the measurement
where your friends thumb grabbed the
6. Try this with the rest of
your friends and record their results.
7. Now let one of your friends
hold the ruler and let you have a
Who had the quickest reaction?
The person who catches the ruler at
the lowest end of the ruler has the
This sense of sight sends
nerve signals to the brain when it
sees the ruler being dropped and then
back out to the muscles in the arm
and hand to catch the ruler.