..... Stumper Index
Stumper #16.
H
o
w

g
o
o
d

i
s

y
o
u
r

s
c
i
e
n
c
e

K
Q
?

How Good Is Your Science KQ?

[i.e. your Knowledge Quotient]

- What "Law of Nature"? -

In a recent addition to our home library, National Geographic's "Everyday Science Explained" (1966), the author describes the 'seething activity' that is going on in a seemingly calm and quiet place where, for example, someone might be reading the morning paper. He talks of light rays slamming into the paper at about 186,000 miles per second, of invisible air 'writhing restlessly' throughout the room, of body cells busily using and manufacturing organic chemicals, and of the Earth spinning at hundreds of miles an hour while racing around the sun at about 18 miles per second. These things are not directly relevant to this stumper but I use them as examples of fascinating and essential things that happen around us all the time but to which we generally pay little or no attention. The stumper this time involves an everyday 'law of nature'. I wonder if you have paid enough attention to things around you to be able to answer this question correctly!

The stumper ...

Having grown tired of trying to make my yo-yo do the trick I want it to, I start twirling it above my head on the end of its string in a whir of circular motion. Suddenly distracted by a barking dog I let the string slip from my fingers. Now, here is the question:
  1. Will the yo-yo continue on its course circling around my head,
  2. will it move away in a sweeping curve and land safely on the lawn, or
  3. will it change its course and fly in a straight line from my hand toward the kitchen window?
When you've settled on your answer, can you explain why you think the yo-yo will behave the way you predict? In other words, which law of nature is being obeyed?

And, something else for you to ponder: What forces other than the constraining string were acting upon my yo-yo before and after I let it go?


[Home]
Send feedback to
Explorit Science Center, P.O. Box 1288, Davis, CA 95617, USA
Phone: (530)756-0191     Fax: (530)756-1227