Top 10 illusions factsTechnology quiz
Which area is brighter? Both are the same.
This is the well known checker shadow illusion, first published in 1995 by Edward H. Adelson, Professor of Vision Science at MIT. The area A appears darker because of its light surrounding. At the same time, area B, surrounded with dark areas, appear lighter.
How many dots at the intersections are black? None.
In this scintillating grid illusion, dark dots seem to appear and disappear randomly. Various theories have been proposed to explain it. It may be caused by the mechanism of lateral inhibition (the capacity of an excited neuron to reduce the activity of its neighbors).
The bright circle around the Sun seen in the picture is known as a halo. What causes it? Refraction of light in ice crystals.
Halo is the name for a family of optical phenomena produced by light interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Among the best known halo types are the circular halo (properly called the 22° halo), Other common optical phenomena involving water droplets rather than ice crystals include the glory and the rainbow.
Which of the lines on the right, is the continuation of the black line on the left? Red one.
This is known as Poggendorff illusion, first described in 1860. Many detailed studies of the illusion point to its principal cause: acute angles in the figure are seen by viewers as expanded.
This is a rare phenomenon called iridescent clouds. It occurs in the clouds with ... Small droplets or ice crystals.
The effect is similar to irisation. Iridescent clouds are a diffraction phenomenon caused by small water droplets or small ice crystals individually scattering light. Larger ice crystals do not produce iridescence, but can cause halos, a different phenomenon.
Which line is the longest? All are the same.
This illusion has a long research history. It seems that people living in urbanized areas perceive the lines as representing the corners of rectilinear objects viewed in perspective, being more susceptible to illusion than people from rural areas.