UNIT 7 NATURAL SCIENCE: HEAT

WHAT IS HEAT?

Heat is the transfer of thermal energy from something hotter to something cooler. For example, if we touch a hot plate, thermal energy goes from the plate to our skin, so our skin gets hotter.

This flow of energy causes changes. For example, ice cream melts because there is a transfer of energy from the warmer air to the cooler ice cream.

WHAT IS TEMPERATURE?

Temperature tells us how hot or cold an object is. In order to know the temperature of an object, we use thermometers. Temperature is measured in degrees Celsius (ºC).

When two objects at different temperatures como into contact, heat goes from the hotter object to the cooler object until both reach the same temperature. For example, if we leave a cup of hot chocolate on a table, heat goes from the hot drink into the air until both reach the same temperature.

HEAT TRANSMISSION

Depending on how they transmit heat, material can be classified into two types:

• CONDUCTORS: these are materials that transmit heat quickly. Metals are good conductor of heat. For this reason, many pots and pans are made of metal.
• INSULATORS: these are materials that transmit heat very slowly. Cork, glass, plastic, wood and wool are heat insulators. For example, many winter clothes are made of wool, so heat doesn't pass from our bodies to the colder air around us.