| Term | Definition |
| dependent variable | factor in an experiment that can change if the independent variable is changed |
| control | standard for comparison in an experiment |
| hydrosphere | all the water in Earth's oceans, lakes, seas, rivers, and glaciers plus all the water in the atmosphere |
| environmental science | study of the interactions of humans with environment |
| independent variable | factor that is manipulated by the experimenter in an experiment |
| geosphere | the part of Earth from its surface to its center |
| biosphere | all of Earth's organisms and the environment in which they live |
| scientific model | an idea, a system, or a mathematical expression that represents the idea being explained |
| hypothesis | a testable explanation of a situation |
| scientific law | a principle that describes the behavior of a natural |
| astronomy | study of objects beyond Earth's atmosphere |
| scientific methods | a series of problem-solving procedures that help scientists conduct experiments |
| geology | study of material that make up Earth and the processes that form and change these materials, and the history of the planet and its life-forms since its origin |
| atmosphere | blanket of gases surrounding Earth that contains about 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases such as argon, carbon dioxide, and water vapor |
| oceanography | study of Earth's oceans including the creatures that inhabit its waters, its physical and chemical properties, and the effects of human activities |
| meteorology | the study of the atmosphere, which is the air surrounding Earth |
| scientific theory | an explanation based on many observations during repeated experiments; called only if consistent with observations, can be used to make testable predictions, and is the simplest explanation; can be changed or modified with the discovery of new data |
| Le Systeme International d'Unites | replacement for ht emetric sustem; based on decimal system sinf the number 10 as the base unit; includes the meter: (m), second (s), and kilogram (kg) |
| scientific notation | a method used by scientists to express a number as a value between 1 and 10 multiplied by a power of 10. |
