Have you ever observed the vessels used for cooking in the kitchen?
Answer
Yes — and one thing stands out: the part that sits on the fire is always metal, while the part your hand holds is usually not metal.
The tawa, kadhai, pressure cooker and patila are made of aluminium, steel, iron or copper.
Their handles are wood, bakelite or plastic, or the metal handle is wrapped in cloth.
Why it happens: the vessel must let heat pass from the flame into the food quickly, so it is made of a metal — a good conductor of heat. The handle must stop heat from reaching your fingers, so it is made of a poor conductor.
Q2.
Can you name some metals that are used for making cooking vessels?
Answer
Metal
Where you see it in the kitchen
Why it suits the job
Aluminium
Pressure cooker, patila, tawa
Very good conductor, light, cheap
Iron
Kadhai, tawa
Strong, stands high heat, spreads heat evenly
Copper
Base of steel vessels, bhagona
The best conductor of heat among common metals
Steel (iron + carbon)
Most modern vessels
Good conductor and does not rust easily
Tip: look at the bottom of a good steel patila — many have a copper or aluminium disc fixed there. Steel alone conducts heat rather slowly, so a better conductor is added exactly where the flame touches.
Q3.
Do you know why these metals are used for this purpose?
Answer
Because metals are good conductors of heat.
Flame heats the base of the vessel
Heat travels through the metal by conduction
Heat reaches the food and cooks it — quickly and evenly A vessel of wood or clay would be far slower, and wood would simply burn.
Why it happens: in a metal, heat is passed on rapidly from particle to particle right through the piece, so the whole vessel becomes hot in seconds. In wood, plastic or clay this passing on is very slow, which is why the same materials are chosen for handles.