An atom is the smallest component of an element that still retains the properties of the element.

In the liquid state, molecules flow freely around each other and exist at a higher temperature range than the same substance in a solid state. Liquids maintain a constant volume but their shape depends upon the shape of their container.

The Cambrian period is one of the most significant geological time periods. Lasting about 53 million years, it marked a dramatic burst of changes in life on Earth known as the Cambrian Explosion. It is from this period that the majority of the history of life on Earth, as documented by fossils, is found. Called the fossil record, the layering of these mineralized imprints of organisms preserved in sedementary rock have allowed geologists to build a historical record of plant and animal life on Earth.

Power is the rate at which work is performed or work per unit time:  \(P = {w \over t}\)  and is measured in watts (W).

Newton's law of universal gravitation defines gravity: All objects in the universe attract each other with an equal force that varies directly as a product of their masses, and inversely as a square of their distance from each other. Expressed as a formula:  \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) where r is the distance between the two objects and G is the gravitational constant with a value of 6.67 x 10^-11.