Activity 3.5 NCERT Class 10 Science, Chapter 3 Metals and Non-metals
The activity asks us to heat a metal wire which is attached to a pin at its corner by a wax.
The pin drops immidiately once we start heating the wire.
Metals are a good conductor of heat. Here, once we start heating, heat transfers to the area of wax. It melts the wax. So, the pin drop on the table.
This experiment demonstrates that metals are a good conductor of heat.
Processor cooler in computers and laptops: In a computer and a laptop CPU is the most important chip. During data processing, it generates a lot of heat. To dissipate the heat, a CPU is connected to a copper or aluminium heat sink. Due to the thermal conductivity of metals heat transfers to the heat sink. A fan at the sink blows the hot air outside.
Cooking utensils: Cooking utensils consists of a metal or metal alloys. It receives heat from the gas stove and transfers heat to the food.
Metals have free electrons in their valance shell. When we heat a metal, their electrons vibrate and transfer heat to another electron. As a result, metals are a good conductor of heat.