Extra Explaining Questions - MEASUREMENT OF THERMAL ENERGY

MEASUREMENT OF THERMAL ENERGY

1. When hot water is poured to put off the fire, some hot water dropped to the people and caused less burning compared to that was caused by vapour. Explain why vapour caused severe burning.
   [Show answer]

   Vapour caused severe burning because it contain large amount of heat (Latent heat of vaporization) which is greater than the hot water which is at boiling point.
2. Explain why a drop of methylated spirit placed at the back of hand feels much colder than a drop of distilled water at the same temperature.
   [Show answer]

   Methylated spirit evaporates more quickly than water. When it evaporates draws heat from your body skin making hand to cool.
3. Use your Physics knowledge to answer the following;
   1. When we take exercise we sweat. Even on a warm day having wet skin can soon make you feel cold. Why does sweating help us stay cool?
   2. Even on a warm day having wet skin can soon make you feel cold. Explain why.
4. Animals that live in extreme climates have adapted to control their rate of heat transfer. For example, animals in hot climates often have larger ears than those that live in cold climates.
   1. Explain how having large ears could be an advantages to an animal living in a hot climate.
   2. In hot conditions, many animals sweat. Explain, in terms of energies, how sweating will help keep an animal cool
5. When a drop of ether is placed on the skin, the skin feels cold. Explain why.
6. An ice cube at a temperature of 0°C is more effective in cooling a drink than the same mass of water at 0°C
7. A solid is heated at a constant rate until it become a gas. Figure below shows how temperature of the substance increases with time.
   
   1. Explain why the temperature of the substance remains constant over the periods
   2. At what temperature does the substance melt?