Taken from Barron's ACT Math and Science Workbook
Terms : Hide Images
| 695607623 | Absolute zero | Approximately -273° C; the lowest possible temperature | |
| 695607624 | Acid | A compound that releases hydrogen ions when dissolved in water; has a pH of less than 7 | |
| 695607625 | Algae | Simple, one-celled plantlike organism found in water or damp places; includes seaweeds, pond scum, and so on | |
| 695607626 | Alloy | A substance composed of two or more metals | |
| 695607627 | Atmosphere | The layer of air surrounding Earth | |
| 695607628 | Atmospheric pressure | The pressure exerted by the atmosphere on every part of Earth's surface; approximately 10 newtons per square centimeter | |
| 695607629 | Atom | The smallest part of an element that is recognizable as that element | |
| 695607630 | Barometer | An instrument that measures atmospheric pressure | |
| 695607631 | Base | A compound that releases hydroxide ions in water; has a pH of more than 7; is sometimes called an alkali | |
| 695607632 | Boiling point | The temperature at which additional thermal energy causes a substance to change from a liquid to a vapor | |
| 695607633 | Calorie | A quantity of heat energy; the amount needed to raise the temperature of one gram of water 1° C | |
| 695607634 | Carbohydrate | An organic compound-like sugar or starch that contains carbon, hydrogen, and oxygen in the ratio of 1:2:1; the human body's main source of energy | |
| 695607635 | Carcinogen | A cancer-causing agent | |
| 695607636 | Carnivore | Meat-eater | |
| 695607637 | Catalyst | A substance that speeds up a chemical reaction without being changed by the reaction | |
| 695607638 | Cell | The lowest-level structure of any living organism that can perform all the functions of life, including reproduction | |
| 695607639 | Chlorophyll | The main pigment in plants that captures light energy during photosynthesis | |
| 695607640 | Compound | A substance composed of two or more chemically bonded elements | |
| 695607641 | Concentration | The exact amount of substance dissolved in a given amount of solvent; refers to a solution | |
| 695607642 | Condensation | The process whereby a decrease in energy causes vapor particles to return to a liquid phase | |
| 695607643 | Conductor | A material that allows heat or electricity to flow through it with minimal resistance | |
| 695607644 | Control | A sample in which no variables are tested, thus serving as a basis for comparison | |
| 695607645 | Control variable | A variable that stays constant in an experiment, allowing the effect of another variable to be measured | |
| 695607646 | Convection | The circulation of fluid caused by warm fluid rising and cool fluid sinking | |
| 695607647 | Density | In a physics sense, the amount of mass per unit volume; in a more general sense, the quantity per unit area or volume | |
| 695607648 | Diffusion | The scattering of light; the spreading of a liquid or gas from areas of higher concentration to areas of lower concentration | |
| 695607649 | DNA | Nucleic acid in the cells of an organism; contains the genes of an organism and transmits these to future generations | |
| 695607650 | Ecological succesion | A sequence of changes in the plant and/or animal life of a region over time | |
| 695607651 | Electron | A negatively charged fundamental atomic particle | |
| 695607652 | Element | A substance consisting of exactly one type of atom | |
| 695607653 | Erosion | Wearing away; typically the washing away of sand or rock by running water or wind | |
| 695607654 | Evaporation | The changing of a fluid into gas | |
| 695607655 | Fossil | The preserved remains of a very old organism | |
| 695607656 | Frequency | The number of cycles per unit time of a repeating phenomenon | |
| 695607657 | Glucose | A simple sugar that is broken down to provide energy to an organism | |
| 695607658 | Habitat | The part of an ecosystem where a plant or animal naturally grows or lives | |
| 695607659 | Herbivore | An animal that eats only plants | |
| 695607660 | Hormone | A chemical substance secreted by a gland of the body that affects other parts of the body | |
| 695607661 | Humidity | The amount of water vapor in the air | |
| 695607662 | Hypothesis | A statement that is a proposed explanation of a scientific phenomenon | |
| 695607663 | Infrared radiation | Electromagnetic waves whose wavelength is longer than that of visible light | |
| 695607664 | Insulator | A substance that blocks the flow of heat or electricity | |
| 695607665 | Ion | A molecule or atom that has become charged by either gaining or losing an electron | |
| 695607666 | Isotope | A variety of an element with the same number of protons per atom but a different number of neutrons | |
| 695607667 | Kinetic energy | The energy of an object due to its motion | |
| 695607668 | Melting point | The temperature at which additional thermal energy breaks the chemical bonds holding a substance together and causes the substance to change from the solid to a liquid state | |
| 695607669 | Molecule | The smallest unit of a chemical compound | |
| 695607670 | Neutron | A fundamental atomic particle that has no charge | |
| 695607671 | Ore | A piece of rock from which metal can be profitably extracted | |
| 695607672 | Osmosis | The movement of liquid through a membrane | |
| 695607673 | Parasite | An organism that invades another organism and feeds off it | |
| 695607674 | pH | A numerical scale from 1-14 representing the acidity or alkalinity of a solution; 1 is very acidic, 14 is very alkaline, and 7 is neutral | |
| 695607675 | Photosynthesis | The process in which plants use the sun's energy to convert carbon dioxide and water into glucose | |
| 695607676 | Pressure | Force per unit area | |
| 695607677 | Protein | A complex molecule composed of amino acids that carries out a variety of processes in cells | |
| 695607678 | Proton | A positively charged fundamental atomic particle | |
| 695607679 | Starch | A complex carbohydrate found in potatoes, rice, corn, and many other vegetables | |
| 695607680 | Symbiosis | A close relationship between two organisms that is mutually beneficial | |
| 695607681 | Ultraviolet radiation | Electromagnetic waves with wavelength shorter than that of visible light | |
| 695607682 | Vapor | The gaseous form of a liquid | |
| 695607683 | X ray | Electromagnetic radiation with wavelength shorter than ultraviolet radiation |
