Phase Change Diagram Science Worksheets printable pdf download

Phase Change Diagram Science Worksheets

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Phase Change Diagram

Heat plays an important role in phase changes. Heat is energy that causes particles of matter

to move faster and farther apart. As particles move faster, they leave one phase and enter another.

Phase changes produce changes in only the physical properties of matter. They do not produce

changes in the chemical properties. A substance is still the same kind of matter regardless of its

phase.

Examples of phase changes include melting, freezing, condensation, evaporation, and

sublimation. Melting occurs when a solid changes to a liquid. Freezing occurs when a liquid

becomes a solid. Condensation involves a gas becoming a liquid. Evaporation involves a liquid

becoming a gas and sublimation is the change of a solid directly to a gas. Phase changes require

either the addition of heat energy (melting, evaporation, and sublimation) or subtraction of heat

energy (condensation and freezing).

The diagram below is called a phase-change diagram. It shows how heat-energy and

temperature are related as an ice cube becomes steam. Changing the amount of heat energy usually

causes a temperature change. However, DURING the phase change, the temperature stays the same

even though the heat energy changes. This energy is directed into changing the phase and not into

raising the temperature. That's why the temperature of water doesn't increase as it is boiling. The

temperature remains constant until the phase change is complete.

Read the paragraphs above, then study the diagram and answer the

questions on the back of this paper.

Phase Change Diagram Science Worksheets