Chemical and Physical Changes

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What is a physical change?

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A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include changes in state (like melting or freezing) and changes in shape (like cutting or crushing).

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What is a chemical change?

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A chemical change is a change that results in the formation of new chemical substances. It involves a chemical reaction and changes the chemical composition of the substance. Examples include rusting, burning, and baking.

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What happens when a window is broken?

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Breaking a window is a physical change because it alters the shape and structure of the glass but does not change its chemical composition.

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What happens when metal rusts?

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Rusting is a chemical change because it involves a reaction between metal and oxygen, resulting in the formation of a new substance, iron oxide (rust).

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What happens when a cake is baked?

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Baking a cake is a chemical change because it involves a series of chemical reactions that transform the ingredients into a new substance with different properties.

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What happens when a soda can is crushed?

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Crushing a soda can is a physical change because it changes the shape and size of the can without altering its chemical composition.

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What happens when a popsicle melts?

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Melting a popsicle is a physical change because it changes the state of the substance from solid to liquid without changing its chemical composition.

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What are examples of physical changes?

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Examples of physical changes include melting ice, boiling water, dissolving sugar in water, and breaking glass.

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What are examples of chemical changes?

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Examples of chemical changes include burning wood, cooking an egg, rusting iron, and baking bread.

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How can you tell if a chemical change has occurred?

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Signs of a chemical change include color change, gas production (bubbles), temperature change, and the formation of a precipitate (solid).