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