Heat water in a beaker till boiling and dip a plastic scale, pencil,st

1.	Heat water in a beaker till boiling and dip a plastic scale, pencil,steel spoon, iron nail or wire, aluminium wire as shown in fig. Wait for some time, than touch the upper end of the objects. The upper end of which of the objects have become hot? Heat flows easily in metals aluminium,iron,steel, etc. That is why the upper end of all these meterials are hot. Now, you may have understood why wood, plastic,etc. are less hot?The materials which allow heat to pass through them easily are called heat conductors. In opposition, the materials which do not allow heat to pass through them easily are called bad conductors of heat or heat insulators. For example metals like aluminium, iron and copper, etc., are conductors of heat whereas plastic, wood, ebonite, woollen cloths, insulators of heat.1. Upper end of which of the object has become hot?2. What are good conductors of heat?3. Plastic and wood on heating become less hot. Give reason why?4. Cooking utensils are made of metals and their handles are covered by materials like wood or ebonite why?5. Stainless steel pots has a copper base why?6. During summers, why is it less troublesome to walk bare foot on mat or carpets as covering of heated floor?
Answer» 1. Heat is easily transferred in the objects made of aluminium, steel spoon, iron wire, Therefore, upper end of these things have become hot. 2. Those substances in which heat is transferred easily are called good conductors of heat. 3. Materials like plastic and wood are bad conductor of heat therefore, on heating, heat is not transferred. So they become less hot. 4. Metals are good conductors of heat, food is cooked easily in the utensils made from metals. Therefore cooking utensils are made of metals which are conductor of heat, so handles of cookwares are covered with ebonite or wood to protect our hands from burning. 5. Copper is the best conductor of heat. Therefore, to cook food quickly a layer of copper is pasted at the bottom of pans made of steel. 6. Mats and carpets are bad conductor or insulator of heat, They do not absorb heat from heated floor. Therefore, it is less troublesome to walk on them during summer

Heat water in a beaker till boiling and dip a plastic scale, pencil,steel spoon, iron nail or wire, aluminium wire as shown in fig. Wait for some time, than touch the upper end of the objects. The upper end of which of the objects have become hot? Heat flows easily in metals aluminium,iron,steel, etc. That is why the upper end of all these meterials are hot. Now, you may have understood why wood, plastic,etc. are less hot?The materials which allow heat to pass through them easily are called heat conductors. In opposition, the materials which do not allow heat to pass through them easily are called bad conductors of heat or heat insulators. For example metals like aluminium, iron and copper, etc., are conductors of heat whereas plastic, wood, ebonite, woollen cloths, insulators of heat.1. Upper end of which of the object has become hot?2. What are good conductors of heat?3. Plastic and wood on heating become less hot. Give reason why?4. Cooking utensils are made of metals and their handles are covered by materials like wood or ebonite why?5. Stainless steel pots has a copper base why?6. During summers, why is it less troublesome to walk bare foot on mat or carpets as covering of heated floor?

Answer»

1. Heat is easily transferred in the objects made of aluminium, steel spoon, iron wire, Therefore, upper end of these things have become hot.

2. Those substances in which heat is transferred easily are called good conductors of heat.

3. Materials like plastic and wood are bad conductor of heat therefore, on heating, heat is not transferred. So they become less hot.

4. Metals are good conductors of heat, food is cooked easily in the utensils made from metals. Therefore cooking utensils are made of metals which are conductor of heat, so handles of cookwares are covered with ebonite or wood to protect our hands from burning.

5. Copper is the best conductor of heat. Therefore, to cook food quickly a layer of copper is pasted at the bottom of pans made of steel.

6. Mats and carpets are bad conductor or insulator of heat, They do not absorb heat from heated floor. Therefore, it is less troublesome to walk on them during summer

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