Heat (High Cohesion)
Heat (Low Cohesion)
Orlando (High Cohesion)
Orlando (Low Cohesion)
Effects of Heat
Moving Heat .Heat can move from one object or place to another. Heat moves from warm objects to cooler ones. You can warm your hands by holding a cup of warm soup. Heat moves from the soup through the cup to your hands. You can feel warm air rising above the cup. Heat moves through some materials more easily than others. Heat moves easily through conductors. Most metals are good conductors. Metal pots are used for cooking. Heat from the stove quickly moves through the metal. The heat warms the food.
Other materials are not good conductors. But they may be good insulators. Insulators help keep heat from passing through. Most plastics are good insulators. So are clothes you wear, like sweaters and coats. You wear these clothes to keep warm when it is cold outside.
Changing Matter. Adding or taking away heat can change matter. Matter is something that takes up space. Matter can change from one state, or form, to another. An ice cube is solid water. Solid is one state of matter. Heat can melt an ice cube. The ice cube changes into liquid water. Liquid is another state of matter. When heat is taken away, the water can change back. Liquid water turns into solid water.
Heat can make liquids boil. Water boils when it is heated. When the water boils, it turns into a gas. This gas is called water vapor. Solid, liquid and gas are three states of matter. Heat from the sun causes liquid water to turn into water vapor. Water vapor mixes with the air. This is called evaporation.
Sometimes heat causes changes that cannot be changed back.
Bread can change into toast when you heat it. Eggs change when you cook them in a pan. You cannot untoast a piece of toast. You cannot uncook an egg.
Changing Air. Heat can warm air, too. A balloon is filled with air. When heat warms the air in the balloon, the air changes. The air takes up more space.
Heat from the sun warms objects all around you, like rocks, streets, and buildings. These objects then warm the air. Warm air is lighter than cold air. Warm air goes up. Cold air takes its place
You can tell how hot or cold the air is. Temperature is a measure of how hot something is. People use thermometers to measure the temperature.