INTRODUCTION
• HAVE YOU EVER ACCIDENTALLY TOUCHED A CURLING
IRON OR HOT PAN?
• THIS WAS CAUSED BY HEAT TRANSFER FROM THE
OBJECT TO YOUR HAND AT A HIGH RATE
• THIS CAUSES YOUR NERVES TO REACT TO MOVE YOUR
HAND AWAY BEFORE YOU ARE BURNED WORSE.
THE TRANSFER OF HEAT
• HEAT IS DEFINED AS THE TRANSFER OF ENERGY FROM
ONE OBJECT TO ANOTHER. (HOTTER TO COOLER)
• HEAT IS TRANSFERRED IN THREE DIFFERENT WAYS:
RADIATION, CONDUCTION, AND CONVECTION.
RADIATION
• THE SUN'S RAYS ARE AN EXAMPLE OF HEAT FROM RADIATION
• RADIATION IS THE TRANSFER OF ENERGY THROUGH
ELECTROMAGNETIC WAVES.
• YOU CANNOT SEE RADIATION, BUT YOU CAN FEEL IT.
• A GOOD EXAMPLE OF RADIANT HEAT IS AN INFRARED HEATING LAMP.
CONDUCTION
• HAVE YOU EVER TOUCHED HOT PLAYGROUND EQUIPMENT WITH
YOUR HANDS OR FEET?
• THIS IS HEAT BEING PASSED DIRECTLY FROM ONE OBJECT TO
ANOTHER.
• FOR EXAMPLE, THE HEAT IN A FRYING PAN CAN OFTEN TRAVEL UP
THE HANDLE TO WHERE YOU ARE HOLDING IT.
• THAT IS HEAT TRANSFER BY CONDUCTION.
CONVECTION
• IN LIQUIDS AND GASES PARTICLES CAN FREELY MOVE FROM ONE
AREA TO ANOTHER.
• WHEN LIQUIDS AND GASES ARE HEATED THE MOVEMENT BECOMES
FASTER.
• HEATED PARTICLES WILL RISE AND EVENTUALLY COOL.
• THESE COOLED PARTICLES WILL MOVE DOWNWARD AND GET CLOSER
TO THE HEAT SOURCE WHERE THE CYCLE STARTS OVER AGAIN.
CONVECTION