This video tutorial from Homk Middle School's Earth Science Department focuses on phase changes, particularly those of water. It explains how substances transition between solid, liquid, and gas phases, emphasizing the role of heat energy. The concept of latent heat is introduced, highlighting water's unique ability to change temperature or phase, but not both simultaneously. The tutorial details the specific phase changes of water, including melting, freezing, evaporation, and condensation, and discusses the heating and cooling curve of water.

What is the first thing that should come to mind when thinking about phase changes?

• A substance changing its chemical composition

• A substance changing its density

• A substance changing from solid to liquid to gas

• A substance changing color

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What usually happens when you apply heat energy to a substance?

• It changes its color

• It changes its phase from solid to liquid to gas

• It changes its chemical composition

• It becomes denser

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What is the term for the hidden form of heat energy found in water?

• Thermal energy

• Sensible heat

• Latent heat

• Specific heat

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What is the unit of heat energy used in the context of phase changes of water?

• Calorie

• Watt

• Kilowatt

• Joule

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How many joules per gram are required for the melting of water?

• 2260 joules per gram

• 1000 joules per gram

• 334 joules per gram

• 500 joules per gram

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What phase change occurs when water vapor cools down?

• Freezing

• Melting

• Condensation

• Evaporation

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How many joules per gram are required for the evaporation of water?

• 334 joules per gram

• 2260 joules per gram

• 500 joules per gram

• 1000 joules per gram

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NGSS.MS-PS1-4

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What is the phase change called when a solid turns into a liquid?

• Freezing

• Melting

• Evaporation

• Condensation

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What does a slanted section on the heating and cooling curve of water represent?

• A chemical reaction

• A temperature change

• A phase change

• A change in density

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What does a plateau or horizontal region on the heating and cooling curve of water indicate?

• A temperature change

• A chemical reaction

• A phase change

• A change in density

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