Question

Answer in Detail (Summative Assessment):-
1. How is temperature measured with a thermometer?
2. Distinguish between clinical and laboratory thermometers.
3. List the precautions that should be taken while taking temperature.
4. (a) What do you mean by good and bad conductors of heat? Give examples.
(b) Give two applications each of good and bad conductors of heat.
5. With the help of an experiment, show convection current in liquids.
6. With the help of an experiment, show conduction of heat in solids.
7. What are sea breeze and land breeze? Explain.​

Answer 1

Answer:

1. A thermometer measures temperature through a glass tube sealed with mercury that expands or contracts as the temperature rises or falls. The tiny size of the bulb and micro-fine size of the tube help the mercury reach the temperature of what it is measuring very rapidly.
2. The clinical thermometer is used to measure body temperature, however, laboratory thermometer is not used for the purpose of measuring body temperature. The clinical thermometer is can be tilted while reading the temperature values whereas laboratory thermometer need to be kept upright.
3. ... the reading should be taken by keeping the level of mercury along the line of sight.
4. before use the mercury level should be below 35°C.
5. wash the thermometer with the water before and after use.
6. never hold the thermometer by bulb while reading it.
7. Good Conductors of heat refers to the things which transfer heat from one to another. Bad conductors are those substances which do not or conduct poorly the heat from one end to another. Examples: Good Conductor- Metals- Silver and Copper. air , water , and most liquids and gases are bad conductor of heat .
8. On heating the bottom of the flask with a very small gas flame an upward current of colored water will ascend from the place where heat is applied. This colored stream reaches the top and spreads out. After a short time it circulates down the sides of the flask, showing that a convection current has been set up.
9. Take a few rods each made of a different substance (for example, three different metal rods). If the metal is a good conductor of heat, the wax will melt fairly quickly (because the heat will have passed all the way through the rod), dropping the coin. ...
10. Land breeze blows during the night from land to sea and the land becomes cooler faster than the sea. The air above the sea becomes less dense (i.e. warmer) and rises. The cooler air from the land moves in to take its place. Sea breeze: Sea breeze blows during the day and the land heats up faster than the sea.