water cycle the movement of water between Earth’s surface and atmosphere atmosphere the mixture of gases and dust that surrounds Earth evaporation the change from a liquid to a gas water vapor water in a gas form transpiration the process by which plants release water vapor into the air from their leaves condensation the change from a gas to a liquid precipitation any form of water that falls from the atmosphere run-off water that flows over the land surface and into bodies of water such as rivers, lakes, and oceans infiltration happens when water soaks into the soil from the ground level moves underground between the soil and rocks. some of the water is soaked up by roots to help plants grow. some of the water keeps moving down into the soil to a level that is filled with water, called groundwater. http://dnr.wi.gov/org/caer/ce/eek/earth/groundwater/infil.htm groundwater water located beneath the surface of the earth accumulation the part of the water cycle in which water gathers in large quantities such as rivers, lakes, oceans, glaciers, ice caps and aquifers matter anything that has mass and takes up space physical a feature that you can observe with your property senses or measure with a tool mass the amount of matter that makes up an object weight a measure of the pull of gravity on an object’s mass volume the amount of space an object takes up; density measure of how light or heavy something is for its size. density = mass/volume physical A change in the size, shape or state of change matter. No new materials form. A change from one state of matter to another is a physical change because no new material is formed. Can be caused by motion, pressure, temperature. Example: If you cut a sheet of paper into pieces, you’ve changed the size and shape but, it is still paper. chemical a change in which one or more new types change of matter form – the new substance has different chemical properties than the original substance Signs of Chemical Changes: new material is formed change of color - banana changing from green to yellow to brown; fruits changing color when they rot gases are given off – when you add baking soda to vinegar, the liquid bubbles and gives off carbon dioxide light or heat appears Chemical changes are much harder to reverse than physical changes – most can’t be reversed .