Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
Decibel is a unit used to measure the intensity of a sound or the power level of an electrical signal by comparing it with a given level on a logarithmic scale.
The Richter magnitude scale (also Richter scale) assigns a magnitude number to quantify the size of an earthquake.
Kaleidoscope operates on the principle of multiple reflection, where two or more reflectors are placed at an angle to one another. When the eye is placed at one end of the reflectors, the original view from the aperture on the other side is multiplied into a symmetrical mosaic pattern. A two-mirror kaleidoscope yields a circular pattern isolated against a solid black background, while the three-mirror equilateral triangle type yields an infinite pattern that fills the entire visual field.