Science Unit
Glossary

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Adsorption

The capability of all solid substances to attract to their surfaces molecules of gases, water or solutions with which they are in contact.
Examples:
1. Silica gel has the ability to remove moisture from air through adsorption of water molecules to its surface.
2. Charcoal is the material that is used in gas masks to remove poisons or impurities from air via adsorption of these impurities to the charcoal surface.
Atom
 Atoms make up everything in the universe. Each element on the Periodic Table is one type of atom.
Atom is the smallest particle of a chemical element that can take part in a chemical reaction.

Breathalyzer
A portable breath-testing machines to find out whether a driver has a blood alcohol level above the legal limit.
Bucky Ball
 A molecule of buckminsterfullerene. Examples of this type of shapes include soccer balls and Vancouver's Science World.
Chemical bonding
 A strong force ofattraction holding atoms together in a molecule or crystal.

Chemical Reaction
When substances are mixed and new substances are formed, a chemical reaction has occurred.
Chemistry
 The study of the elements, the compounds they form, and the reactions they undergo.
Crystal
 A crystal is a solid with a definite geometric shape. The shape consists of smooth, flat surfaces that meet in sharp edges or corners.
Crystallography
 A branch of Chemistry that studies crystals and their structure.
Cube
 A cube has three squares at each corner
Dessicant
 A desiccant is a substance that absorbs moisture from the air. Desiccant is useful for protecting any sort of sensitive materials from moisture.

To reuse the desiccant, heat it in an oven for a few hours. This will remove the absorbed water.
Dodecahedron
 A dodecahedron has three regular pentagons at each corner
Electron
 A stable subatomic (smaller than an atom) particle with a charge of negative electricity.
Element
 There are over 100 different elements on the Periodic Table. Some of them occur naturally on Earth, and some of them are man-made.

Endothermic

A chemical reaction that releases heat is called an exothermic reaction.

Ethanol
The key ingredient in alcoholic beverages.

Exothermic

 A chemical reaction that absorbs heat from the environment is called an endothermic reaction.
Hexagon
 A plane figure with six sides and angles.
Icosahedron
 An icosahedron has five equilateral triangles at each corner
Molecule
 A compound formed by two or more atoms joined together by chemical bonds.
Nucleation

When solute molecules in a saturated solution encounter a dust particle or a solid surface (like a string or a seed crystal), they will tend to adsorb and aggregate on the surface. The solid surface provides the nucleation site for the formation of crystals.
Nucleus
 The nucleus is made up of positively charged particles called protons, and neutral particles called neutrons.
Octahedron
 An octahedron has four equilateral triangles at each corner
Osmosis
 Osmosis is the movement of water across a semi-permeable membrane from areas of low solute concentration to areas of high solute concentration.
The Periodic Table
 The Periodic Table is a collection of information about every element in the universe.
Pentagon
 A plane figure with five sides and angles.
Polymers
 Large molecules made up of many smaller molecules or monomers. These are arranged in a strand-like fashion.

eg - In sodium polyacrylate, the repeating monomer is -CH2-CH(COONa)-
Protons
 A stable elementary particle with a positive electric charge.
Recrystallization
 Recrystallization is a process that has been used to purify solid material by dissolving the solid substance in an appropriate liquid and then having the material come out of solution in crystalline form.
Saturated solution
Solution where the maximum amount of solutes is dissolved in the solvent.

Seed crystal
A starting surface for a growing crystal.
Shape of Crystal
 The atoms in a crystal occupy positions with definite geometrical relationships to each other. This structural arrangement of its atoms. is uniquely defined by the chemistry of the substance and determines the shape of the crystal. In crystallography, the shapes of crystals can be grouped into seven systems:
Cubic Tetragonal Hexagonal Trigonal Orthorhombic Monoclinic Triclinic
Solubility
 The maximum amount of solute that can be dissolved in a certain volume of solvent at a given temperature is known as the solubility of the solute. The solubility of the solute usually increases with an increase of temperature.
Solute
 Dissolved substance in a solution.
Solution
 A uniform mixture of two or more substances. For example, sugar dissolved in water is a solution.
Solvent

The liquid into which the solute is dissolved. The solvent of choice in this lab is water.
Tetrahedron
 A tetrahedron has three equilateral triangles at each corner.
   
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