you need
  • - Gnomon;
  • - line;
  • - horizontal surface;
  • - liquid level to establish a horizontal surface;
  • - Calculator;
  • - table tangent and cotangent.
Find a strictly horizontal surface.Check it with a level.It can be used as a bubble, and the electronic device.If you use a liquid level, the bubble must be strictly at the center.For the convenience of further work to secure the surface of a sheet of paper.It is best in this case to use graph paper.As the horizontal surface can take a solid thick sheet of plywood.It should not have depressions and mounds.
Draw on graph paper point or a cross.Install the gnomon verticall
y so that its axis coincides with your metkoy..Gnomonom called vertically mounted rod or pole.Its top is shaped like a sharp cone.
Gnomon is a vertical rod
In the shadow of the gnomon at the end of the second set point.Mark it as a point A, and the first - as a point C. The height of the gnomon you must be known with sufficient accuracy.The bigger the gnomon, the more accurate the result.
Measure the distance from point A to point C in any way you can.Note that the units are the same as the height of the gnomon.If necessary, place the unit in the most convenient.
On a separate sheet of paper make a drawing using the data.The figure is supposed to be right-angled triangle whose right angle C - Fitting of the gnomon, leg CA - long shadows and leg CB - the height of the gnomon.
Calculate an angle A with the help of the tangent or cotangent, using the formula tgA = BC / AC.Knowing the tangent, determine the proper angle.
resulting angle is the angle between the horizontal surface and a sunbeam.The angle of incidence is the angle between the perpendicular dropped onto the surface, and the beam.That is, it is 90º- A.