IGCSE Physics Section D - Energy resource and transfer: thermal energy

[@vidooshvarun3145]

Understood your lesson very well thnx for your kindness for teaching students for free

[@zainabthahira3531]

Your Method of teaching is really good sir...Please dont stop making videos

[@abodyes7275]

thanks < hope u are happy as u made our class

[@hemendravarshney3230]

Thanx mate for the lectures

[@yogitanaulakha4603]

Saved my exams thank youuu

[@vryam]

Air is an insulator and cant carry heat. SO what difference is it if it is trapped air or free air?

[@Peter-zw8yn]

If the air is free to move then I believe convection can still occur.

[@humanbeans3568]

when convection happens in free air ryt...ee uk the faous example of heater nd an ac..when the heater is switched on the air around it is heated so hot air is less dense than cold air hence it floats up to the ceiling their if the ac if switched on it doesnt mtter if it it on or off either way the hot aair is cooled nd becomes denser than before nd falls down ..ok so all this is happening in free air ryt it is not trapped it iss an insulator but the convection currents cn still take place slowly...however n trapped air the case is diff and so tht trapped air cannot carry heat therefore when the air is trapped in a vacuum flask by the cork the air is trapped nd cannot carry the heat outside of the cork..also by now i m pretty sure tht u know the answer but its fr the other ppl if they hav the same doubt

[@beulahwilliams2785]

I wish more new lecture

[@zihanhossain4394]

Thank you

[@lishashaikh4562]

i didnt understand 1)conduction vs convection 2)the cork thingy

[@sksaad8987]

Lisha Shaikh conduction transfer heat energy through a substance without the substance itsef moving . For exam , if we put a metal spoon in a hot cup of tea the metal spoon will also become because metals consist delocalised electron .Metals are good conductor of heat energy and it also conduct electricity.Conduction happens in metal. Convection is a transfer of energy through fluids ( liquid and gases)

[@sksaad8987]

Sorry the metal spoon will also become hot

[@sksaad8987]

Hope it will help you to understand☺

[@majidalzaydi5230]

K