A1. The assumption that the sun is a point source of light is wrong. If
this were the case, what would be the pattern of shadows we would see at
nightfall? (consider a scenery with mountains)
A. The shadows would race across the ground. At sunset, the sun would
just wink out instead of fading away.
Q2. Sound travels faster in solids than air, BUT solids are not better
conductors. There is a common experiment. Place one end of a wooden
ruler on a ticking clock and the other on your ear and you will be able
to hear it clearly. Explain it.
A. Just as sound from air has trouble going through a wall, sound from a
solid will not pass into the air. It bounces off the air outside the
solid and is guided to your ear. Counter-experiemnt. Place a hollow tube
on the watch and you will still hear it clearly.
Q3. Ben Franklin's kite was not actually hit by a lightning bolt. He did
put fly a kite with a key at the bottom end. So, what happened?(remember, he
discovered electricity)
A. The kite and twine because charged due to electrical leakage in the
air. This was used to charge a key from which a spark could be
extracted. This only suggested that storm clouds carry electric charges
and implied that lightning might be an electric spark.
Q4. Fill a baloon with air and another only partially. The larger one
will displace the smaller one on a beam balance. This is not because the
full baloon actually "weighs" more than the empty one. A baloon which is
blown up to bursting point will displace another which is just full even
thought the volume is almost equal. What lies behind this.
A. Compressed air is heavier than light air. Even if the volume of the
two is almost the same.
Q5. Static electricity is caused by friction. Then, how does running a
plastic wheel on a rubber mat charge it?
A. Only intimate contact is required between the two surfaces. Rubbing
increases contact are
A.
Q6. The Coriolis force is not responsible for the direction in which water flows when it goes down toilet bowl. Can you give me a simple reason why? A, It is not strong enough. The direction water flows in the flush depends on the bore that is made.
Audience: Question about iceskates.