Slides in this set
RADIATION...HOW WE GET HEAT FROM THE
· Heat can be transferred by conduction, convection and radiation.
· Heat is radiated as infrared waves (electromagnetic waves that travel
in straight lines at the speed of light)
But why is radiation different from conduction and convection?…read more
HOW IS RADIATION DIFFERENT FROM
CONDUCTION AND CONVECTION?
· It doesn't need a substance to travel through
· This means it can happen in a vacuum like space
· This is how we get heat from the sun
· Radiation can only occur in transparent materials, like air, water and
· Surface colour and texture affect the amount of radiation emitted or
ALL OBJECTS EMIT AND ABSORB HEAT
· This happens continually. The hotter an object is, the more heat it
· Cooler objects absorb heat radiation from hotter objects.
· This makes their temperature increase.
· We can feel radiation; for example, when the sun shines through a
window onto you.…read more
WHY IS HEAT RADIATION IMPORTANT IN
· Things such as toasters use infrared radiation to cook food.
· Grill pans can be lined with shiny foil to increase the radiation being
reflected onto the food.
· Microwaves use microwaves to heat food (no surprise there)
· However, foil cannot be used in microwaves...that's both dangerous
and stupid because it reflects the microwaves away from the food,
and can cause sparks.…read more