A thermometer with a temperature reading of 22 oC is placed inside a beaker of water. After a few minutes, a student reads the thermometer. The thermometer reads 45 oC Describe the direction of heat flow between the thermometer and the water in the beaker.

Explanation:

The energy flow in the form of heat is a consequence of a difference in temperatures. When two objects with different temperatures are put in contact, the energy will flow from the object with the highest temperature to the one with the lowest temperature.

In this case, the thermometer first had a temperature of 22ºC. Then it was placed in a beaker of water and it read 45ºC. Therefore, the temperature gained by the thermometer is a consequence of the transmission of heat from the water in the beaker, which was at a higher temperature.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

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