ICE CORE: Cylinders of ice that are drilled out of glaciers and polar ice sheets. Ice cores play an important role in helping scientists to gain an understanding of earth's history, particularly how earth's climate has changed over time. Within these ice layers, there is a record of the atmosphere at the time the snow creating the ice layer fell.
IGNEOUS ROCK: A type of rock formed when magma from a volcano cools. Examples of igneous rock include obsidian and basalt.
IMMIGRATION: Movement of individuals into a population. This causes the population to increase in size (grow).
IMPERMEABLE: Does not allow something (such as water) to pass through
INDEPENDENT VARIABLE: What I (the scientist) change in the experiment; the cause.
INDEX FOSSIL: Fossils of unique organisms that lived for a only a short time period, but were found over a wide area of the earth.
INFERENCE: An educated guess based on your observations.
INSULIN: A protein that lowers blood glucose (sugar) levels in the body.
INTERPHASE: The period of growth and DNA synthesis before and after mitosis. If a cell is not dividing, it is in interphase.
INVALID: Not true; not correct; not trustworthy; not reliable.
INVERTEBRATE: Animals that do not have a backbone.
ION: An atom that has a positive or negative charge because it is missing an electron or has an extra electron.
IONIC BOND: A bond created by the attraction between a positive and negative ion.