Changes in Materials Due to Heat

Changes in Materials Due to Heat

Open Ended

Observe the changes to the bread before and after baking. Why do you think the bread turned out this way?

There are many factors that allow matter to change.

We take note of these changes so we can make full use of the materials around us.

Some changes are physical while some are chemical.

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Changes in Materials

Multiple Choice

Which material is undergoing a change in substance (chemical change)?

Different factors can change a material. It is important to note which changes happen when, so we can fully make use of the material.

Heat may affect​ physical properties, volume, state, temperature, or create a chemical change.

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​Changes in Materials Due to Heat

Different substances may change their physical properties when heat is applied.

Rice is tough and smaller when uncooked, while after cooking, it is softer and bigger.​

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​Change in Physical Properties

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Open Ended

What food items change their physical properties after cooking (like rice)?

Heat is energy.

When heat is applied to particles, they move faster and farther apart.

Think of a whistling kettle -the increase in volume produces a sound.

Gases expand much faster than liquids or solids.

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​Increase in Volume

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Open Ended

A rubber balloon floats near a lightbulb. A few seconds later, it pops. Why do you think this happened?

When you spill a little water on your table and wait after a while, it disappears. This is because water absorbed the heat from the air and became water vapor. This is called evaporation.

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​Change in State

Multiple Choice

Moth balls disappear after some time, but there is no sign of wetness around them. What do you think happens?

• They turn from solid to gas directly.

• The moths eat them.

• The wetness is absorbed by the clothes.

When heat energy is applied the particles move around and gain more kinetic energy.

This increase the temperature of the object.

Some materials can hold much more heat energy than others.

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Increase in Temperature

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Multiple Choice

Burn injuries from steam are worse than burn injuries from boiling water. Why do you think this is true?

• Water can heal you.

• Steam holds much more heat than water.

• Steam is faster than water.

Heat may cause chemical change which produces new substances.

​Calcium carbonate (CACO₃) turns into calcium oxide (CaO) and carbon dioxide (CO₂) when heated.

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​Occurence of Chemical Change