ENLARGEMENT FACTOR OF LIGHT

Initially, to evaluate the enlargement factor of the shadow, we have used a laser source of light. Noticing that the ray can not reflect all the shadow, we try to expand the light using a bottle of water.

Then… noticing the various imprecisions that we have made, we follow a more theoretical way, calculating the measures of alpha angle. AC² = AB² + BC² BC = AC * senα senα = BC/AC α = 1 / sen ( BC/AC )

Basing on the measurements taken previously, the sides of the triangles are in a proportion: AB / AD = BC / DE = AC / AE

Having a common angle, the triangles ABC and ADE are similar. For this reason, changing the position of the side BC (screen), the ratios remain constant.

Having a common angle, the triangles ABC and ADE are similar. Having verified the similarity of the triangles, it is possible to find the enlargement factor of the projected.

From the similarity of triangles, we can deduce that The light spreads following straight lines If the trajectory would be a curve, the similarities would not be observed.