| A | B |
| water | A transparent, odorless, tasteless liquid, a compound of hydrogen and oxygen. |
| universal solvent | Water is called the universal solvent because it dissolves more substances than any other liquid. |
| solid | Relative firmness, coherence of particles, persistence of form, a form of matter. |
| liquid | Composed of molecules that move freely among themselves but do not ten to separate like those of gases; neither gas nor solid. |
| gas | A substance possess perfect molecular mobility and the property of indefinite expansion. |
| surface tension | The tightness across the surface of water caused by polar water molecules pulling on each other. |
| thermal energy | The energy of motion in the molecules of a substance. |
| physical weathering | The process that breaks down rock through physical changes. |
| chemical weathering | The process that breaks down rock through chemical changes. |
| sediment | Small, solid particles of material from rocks or organisms which are moved by water or wind, resulting in erosion and deposition. |
| agriculture | The science, art, or occupation concerned with cultivating land, raising crops, and feeding, breeding, and raising livestock; farming. |
| irrigation | The process of supplying water to areas of land to make them suitable for growing crops. |
| hydroelectric power | Electricity produced by the kinetic energy of water moving over a waterfall or dam. |
| turbine | Any of various machines having a rotor driven by steam, water, hot gases, or air. |
| water pollution | The addition of any substance that has a negative effect on water or the living things that depend on water. |
| conservation | The belief that people should use natural resources as long as they do not destroy those resources. |
| adhesion | Molecular force of attraction in the area of contract between unlike bodies that acts to held them together. |
| cohesion | Molecular force between particles within a body or substance that acts to unit them. |
| solubility | Property of a solid, liquid, or gas called a solute to dissolve in a solid, liquid or gas solvent to form a solution. |
| condensation | The process by which a gas, such as water vapor, changes to a liquid, such as water. |
| evaporation | The process by which molecules at the surface of a liquid, such as water, absorb enough energy to change to a gaseous state, such as water vapor. |