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Compiled by I. I. Prusakov
Translated from Russian by Alexander Repyev
Cover: I. Kravtsov, V. Stulikov
Artistic Book Design: I. Kabakov, V.
That's why it would hover in the air hardly falling and
being carried by the slightest wind away and even
A Snake and a
Cut a circle about the size of a glass hole from
a postcard or
To Measure Light
At twice the distance, clearly, a candle illuminates much
weaker. But how many times weaker? Two? No, if you
place two candles at double the distance, you won't
obtain the previous illumination. In or
a cork and place the paper butterfly on the needle's tip
at the point of equilibrium which can be found by trial
and error. The butterfly will rotate quickly if placed
above a warm thing, in fact putting your palm under it
"The bigger, the better, it'll catch more sunlight."
First thing in the morning I ran to inspect our basin.
The water had frozen right through to the bottom.
"What a good lens we'll have," Alex said
for the spoon to swing freely, make it strike something
solid. You'll hear a low-pitched drone as if a bell is
ringing near your ears.
The experiment comes out better if you use
something heavier instead of the spoon.
water pipes burst so often in winter.
The expansion of water on freezing also accounts for
the fact that ice floats on water and doesn't sink. If
water contracted on cooling, just like all other liquids
do, then ice wouldn't flo
Even if you're ignorant of electricity and not even
acquainted with its ABC, you can still do a number of
electrical experiments that would be fascinating and
will, in any case, be useful when you meet
will be those on plastics and sealing-wax (the so-called
amber or negative, charge) and unlike charges are those
on amber and glass which is positive. The ancient
names "amber" and "glass" charges have now go
magnet to an end of the needle and you'll find that it
won't be attracted to the magnet at that end. It may
turn away from the magnet in order that the opposite
end might approach. This is a case of an interaction
The explanation is that the pin at the back of your
eye is here depicted not upside down but directly. The
hole in the card plays the role of a light source
producing the shadow of the pin. The shadow falls on
the pupil and its
In 1913 in Russian bookshops appeared a book by the outstanding educationalist Yakov Isidorovich Perelman entitled Physics for Entertainment. It struck the
fancy of the young who found in it the answers to many of the questions that interested them.