Presentation on theme: "What do we all have in common?. What is the opposite of a conductor? Name a poor conductor of heat? What makes bubble wrap a bad conductor and a good."— Presentation transcript:
What is the opposite of a conductor? Name a poor conductor of heat? What makes bubble wrap a bad conductor and a good insulator? Name a good conductor of heat?
What is a conductor? What is an insulator? Name an effective conductor Name an effective insulator What makes metals good conductors? Why do we need insulators? In which state(s) of matter are particles touching? Which state(s) of matter can flow? Heads or tails?
Heat transfer Conduction Convection Radiation There are 3 types of heat transfer we need to study :
What is convection? Convection Convection is the transfer of heat in fluids. A fluid is a liquid or a gas. A cycle is set up in which heat is transferred
The density of a substance depends on how far apart its particles are. High density Low density
Less dense regions of particles will rise up More dense regions of particles will fall down
Why does hot air rise? Hot air is lighter than cold air Diffusion as there are less particles higher in the air Hot air is less dense than cooler air as the particles spread out The particles get bigger so can reach higher
Statement Order The less dense fluid rises When a substance is heated it expands. The warm fluid is therefore less dense. When it reaches the top it cools and contracts. The more dense fluid sinks. The cycle of rising and falling is the convection current. Convection currents Convection current A Convection current is a cycle of hot air rising and cool air falling