A magnet is a piece of iron which will attract or repel pins, tacks, nails or anything else made of that metal. The word comes from a district in Thessaly, Greece, called Magnesia. It was here that men first noticed that certain black stones attracted iron. These stones were composed of an iron ore called magnetite and were natural magnets. …

A light year is a way of measuring distance. I know that doesn’t seem to make much sense because “light year” contains the word “year,” which is normally a unit of time. Even so, a light year measure distance. When astronomers use their telescopes to look at the planets and the stars, the distances are gigantic. For example, the closest …

Kymograph is an electrical device used in preclinical medical research to record the biological responses (muscular motion, change in BP, and other physiological phenomena) of various tissues. It was invented by Carl Ludwig (1847) to record the change in arterial BP. It consists of an electrically driven gear box with a vertical spindle carrying a drum, and is disengaged before …

The Kuiper belt sometimes called the Edgeworth-Kuiper belt, is a region of the Solar System beyond the planets extending from the orbit of Neptune (at 30 AU) to approximately 55 AU from the Sun. It is similar to the asteroid belt, although it is far larger – 20 times as wide and 20–200 times as massive. Like the asteroid belt, …

A keystone species is a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass. The concept of a keystone species was first introduced by University of Washington professor, Robert T. Paine in 1969. Paine studied …

Jovian planets, also known as gas giants, is a collective term for Jupiter, Saturn, Uranus and Neptune. The term Jovian came from planet Jupiter, which describes the other gas giants in our solar system which are like Jupiter. These planets are surrounded by a number of moons and rings and their rotation is faster than terrestrial planets. Jovian planets have …

First stated by Camille Jordan in 1887, the Jordan Curve Theorem says that any simple closed curve in a plane divides the plane into two disjoint regions (inside and outside of the curve). By simple closed curve, roughly a curve which does not cross itself but eventually joins itself; more formally, the theorem refers to any homeomorphic image of a …

Histogram is a very useful tool in photography, found on all the digital cameras (compact cameras and DSLR cameras), as well as in all the photography editing programs. With the histogram you can analyse the tonal value of the image or in other words: it shows how bright or dark the image is (number of tones captured at each brightness …

The hermit crab is a type of crab that doesn’t have a very hard shell. Since its shell is not strong enough, it uses old shells of other animals for protection, especially that of old whelk. This habit of living in a second-hand shell gives rise to the popular name ‘hermit’ crab. Most hermit crab species live on the ocean …

A heat budget is the perfect balance between incoming heat absorbed by earth and outgoing heat escaping it in the form of radiation. If the balance is disturbed, then earth would get progressively warmer or cooler with each passing year.