Heat Transfer – Conduction Convection and Radiation

thermal energy moves in three main ways conduction convection and radiation the movement of heat within solid object is called conduction conduction also occurs when objects are touching look at the kettle on the stove heat from the flame moves through the metal of the kettle to the water in contact with it inside this is an example of heat conduction butter melting on fry pan is another example of heat conduction when you lick an ice cream it feels cold because heat conducts from your tongue to the ice cream the movement of heat in liquids and gases is called convection the air in hot air balloon is heated by the burner and rises up inside the balloon as the hot air rises the cooler air falls and creates current within the balloon the convection current causes thermal energy in the air to spread through the balloon on hot day you might cool down room with an air conditioner the cold air that blows out from the air conditioner circulates around the room and creates convection currents heat moves from the warmer air to the colder air which makes the air in the room cooler cool hey for the thermal energy to move by conduction and convection it must travel through matter between the sun and the earth is empty space how does the heat from the sun warm the earth and other planets in the solar system the answer is radiation radiation is the transfer of energy through electromagnetic waves look at the man warming by the fireplace the heat from the fire warms the air in the room through convection however the man also receives warmth from the fire directly through radiation the warmth you feel when you place your hands near an electric heater or campfire are examples of heat in the form of radiation we can observe conduction convection and radiation when water in kettle is heated thermal energy moves through the metal to the water by conduction thermal energy moves around the water through convection and finally the heat leaves the kettle and is transferred to its surroundings by radiation hope you had fun learning about heat see you next time don't forget to subscribe