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Sunday, 17 August 2014

S&H

  
                          
 
                   1. Image of the Sun

Place a pair of binoculars in an open window in the direct path of the sun’s rays.
Stand a mirror in front of one eyepiece so that it throws an image of the sun on to the
opposite wall of the room. Adjust the mirror until the image is sharp, and darken the
room.
You would risk damaging your eyes if you looked directly at the sun through
binoculars, but you can view the bright disc on the wall as large and clear as in the
movies. Clouds and birds passing over can also be distinguished and. if the binoculars
are good even sunspots. These are a few hot areas on the glowing sphere, some so big
that many terrestrial globes could fit into them. Because of the earth’s rotation, the
sun’s image moves quite quickly across the wall. Do not forget to re-align the
binoculars from time to time onto the sun. The moon and stars cannot be observed in
this way because the light coming from them is too weak.
                        2. Sun clock
Place a flowerpot with a long stick fixed into the hole at the
bottom in a spot, which is sunny, all day. The stick’s shadow
moves along the rim of the pot as the sun moves. Each hour
by the clock mark the position of the shadow on the pot. If
the sun is shining, you can read off the time. Because of the
rotation of the earth the sun apparently passes over us in a
semi-circle. In the morning and evening its shadow strikes the
pot superficially, while; it midday, around 12 o’clock, the light
incidence is greatest. The shadow can be seen particularly
clearly on the sloping wall of the pot.





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