1.
Insects have compound eyes with multiple optical receptors, though the number
of receptors is less than in the human eye. Howcome they donot go blind from
exposure to the sun?
A. Insect eyes have lenses much smaller than ours. They have wider field
of view, and fewer receptors, so the resolution is less. Diameter of the sun
in the sky is about 1/2 a degree, which means that only between 1 to 3 of the
ommatidia look at it at one time. So, since the exposure isnot prolonged,
they willnot go blind.
2.
When humans dive and surface, they tend to get bends if they come up too fast.
Now, how come that doesnot happen with dolphins and whales, given that their
lungs are proportionally of the same capacity as human lungs?
A. Dolphins dive with just hte air in their lungs and dont take extra nitrogen
down with them. If you breathe dive, you willnot get bends. Scuba divers
inhale what is 80% oxygen, so as they drop to deeper levels, more of the
gas will dissolve in their blood, causing problems when it leaves it upon
their rise.
3.
Woodpeckers tend to peck the wood with alarming frequency and the impact
deceleration tends to be as high as 1200g.(enough to make their eyeballs
fly out, when they dont close them.) Apart from the spongy bone of their
skulls which acts as a buffer, how are they protected from concussions and
brain damage?
A. Since the size of the brain is very small, the ration of brain weight to
surface area is very small allowing hte impact deceleration force to be
spread over a large area, causing less damage than in a human. Also, it
always hits the wood very straight, to avoid any rotational forces on the
brain which would shear neuronal connections and cause a concussion.
4.
Ants on a coffee cup, emerge un-hurt after a session in a microwave??
(you can assume that the ants walk around on the floor)
A. So, one thing is that the metallic cage tends to short the
magnetic field of the microwave, and so arenot affected by it. Also,
due to the standing wave patterns set up by microwaves, there will be
hot and cold regions in the microwave. Ants in a hot region, will move
to a cooler region and their large surface area to volume ration helps
them to cool off when they move to low energy regions.
5.
(Audience?)
Unlike Girraffes which seem to take no precaution in storms, llamas and
elephants tend to huddle together close to the ground to escape storms.
This might seem in vain in light of hte news that seven elephants were
killed at one go in Kruger National Park in South Africa. So, despite
crouching low towards the ground, howcome they didnot survive, when
lightining struck?
A. Well, lightning struck the ground, causing a rise in the potential
of that ground. This step potential, is even greater when the animals
are spread over a larger space, causing an even larger current to
flow, also causing heart attack in the animals.
6.
House flies are sometimes noticed circling hanging lampshades. Throwing a
small piece of paper in the vicinity causes the fly to follow the paper.
Why?
A. Mating ground.Female flies like to perch somewhere when they are going
to mate. A male fly who is ready can take his chance. They are basically
protecting their territory.
7.
Excreta from the same fish, sometimes floats and sinks at other times.
(either way, it doesnot hang around for too long thanks to coprophagia
practised by fish) Explain this phenomenon which is apparently no shitty
matter.
A. So, they pack all their excerta, including gases into gelatinous tubes
before disposal, including gases. Hence...
8.
Lightning strikes water. Who is safer, the fish, or the people in the
metal hulled boat?
A. well you moight find this too easy.
9.
How to gnats manage to fly without getting wet even when it is raining?
A. Just as you cannot hit a fly with your open hand, and need a fly swatter
which has holes to reduce the air pressure wave, rain drops carry a
pressure wave which push the gnat aside.
10.(you are going to hate me for this)
It has been noticed that when a female dog urinates on a patch of grass,
it tends to brown and die. This isnot so with male dogs. Given that their
urine samples have been proven to be chemically smimilar why does this
happen?
A. Well, the style has a lot to do with it. Female dogs let it all out at
one go in one place, on the ground. This quantity of urine is enough to
kill a patch of grass. Male dogs, go in little steps and tend to spread it
out to mark territory. Also, they might let go on vertical surfaces, which
allow for evaporation and absorption of the liquid.
11.
The honey fungus and "Jack O Lantern" tend to glow even after having
been kept for 24 hours in darkness. Howcome or what is it called?
A. Oxidation of luciferin by luciferase. Bio-luminescence.
12.
When you dive underwater, wearing goggles enables you to see rather clearly,
but their absence causes the image to be rather blurred. Why?
A. The human eye focuses light coming into the pupil on the retina, and is
optimised for light which comes from the air. When light comes directly from
the water, it isnot focused properly. Goggles restore the air/eye interface
and enable clear vision.
13.
What causes the wake of a boat to carry for so long, and why is it shaped
thus?
A. Actually not too sure of how to word this. According to Hyugens principle, a
circular wave should form a disturbance at a point. Now, the boat covers many
points as it moves, generating an envelope for all the circular waves, which
is what we see. Due to low viscosity of water, it carries on for long
distances.
14. What would the texture of beer which is in a glass be like in
outer space?
A. Nucleation would be slower, so bubbles would be smaller and remain dispersed
through the liquid instead of floating to the top. Also, unlike on Earth,
where the foam forms at the top, because be bubbles become bigger there, here
it would all remain of the same size and give it foamy texture.
15.(Audience)
This is a hypothetical situation, because beer is off limits for astronauts.
Why?
A.
16.
Large bubbles of around 8mm in diameter are preferred to small ones say 2mm
in diameter for areation purposes in liquids which contain a large amount of
water. Why?
A. A small bubble due to surface tension will act like a small sphere
and move smoothly to the top. A large bubble, when it moves, will
experience pressure differences across its front which will cause it
to flatten. The turbulent forces in its wake will then cause it to
oscillate and so are preferred. They eventually take on a mushroom
shape, to decrease the effect of turbulence.
17.(audience)
Why is it so that in jukeboxes, the bubbles which form, get smaller as they
go upwards and finally disappear?
A. They are made of watervapour, and so, tend to dissolve back as
they rise. They are caused by a heater in the bottom of the column.
The advantage of this is that it is a closed system, and no pump etc
required.
18.
Why does the froth head disappear on some glasses of beer and remain till
the end on others? Irrespective of brand. The drinker maybe?
A. greasy substances which are insoluble in te beer, and have lower
surface tension than the beer, like animal and vegetable fats, tend to
kill foam. Also, depends on whetehr they use dishwashing liquid.