Distortive concave mirror
If the visitor stands far away from the concave mirror, his mirror image is small and upside down. But if he steps close to the mirror, his mirror image is suddenly much larger - and stands upright!
The surface of the concave mirror is curved inwards. Rays of light entering at an angle to its central axis are reflected according to the angle of incidence, as in a flat mirror. Although this is also the case with rays arriving parallel to the central axis, they represent a special case. The angle at which the rays are reflected depends on their distance from the center axis: The further away the rays are from it, the greater the angle of reflection and vice versa. These different deflections allow all reflected rays to intersect at a single point, the so-called focal point.
Further informationson the exhibit "Distortive concave mirror"
If the object is in front of the focal point, the rays are reflected in such a way that they all meet in one place in front of the mirror. A small upside-down image emerges there. If the object is positioned between the focal point and the mirror, an enlarged, upright image is created behind the mirror plane. If the object is positioned exactly in the focal point, the rays are reflected in such a way that they neither intersect in front of the mirror nor behind it.