A Dean Stark is a form of glassware used in certain chemical experiments to extract water from a reaction mixture.   This apparatus was invented by Ernest W. Dean and David D. Stark in 1920. They described it as "an original method for  the determination of the quantity of water and other organic emulsions contained in petroleum".

TLC is a quick technique for separating and identifying compounds present in a mixture by having them pass through a fixed, inert medium (alumina, silica…) with the aid of a mobile solvent (gas or liquid)  which carries them through the medium.  Each component of the mixture travels through the medium at a different rate as a result of its solubility in the solvent and its affinity for the fixed medium.

TLC  is also commonly used to assess the effectiveness of a purification.

Distillation is a very old and common process used to separate the substances composing a liquid  mixture. When the mixture is heated, the constituents vaporize according to their respective boiling temperatures. A receiving flask collects the distillate, produced by condensing the vapor.
Distillation can be used to purify substances, and to obtain:

• gasoline from crude oil
• essential oils from flowers, as in a lavender mash
• alcohol from fermented fruits or grains.

Temperature is a fundamental physical quantity

Illustration of the three commonly used systems to measure temperature: Fahrenheit, Celsius and Kelvin.

The Celsius scale, the one  most widely used, is centigrade: 100 divisions separate the freezing and boiling points of water. In what is now referred to as the English (or American) system, water’s freezing and boiling points are separated by 180°.  The Kelvin Scale (or Absolute Scale) is primarily used only in Science.

• The formula to convert Celsius to Fahrenheit is F = 9*C/5 + 32
• The formula to convert Fahrenheit to Celsius is C = 5*(F - 32)/9
• The formula to convert Celsius to Kelvin is simply  K = C + 273

The half-life of  a given isotope is the amount of time it takes for half of the atoms in a sample to decay. This animation  allows you to address, using three different isotopes,  notions like radioactive decay, carbon dating, half life constant…