chapter 2 electindo.com physics for junior high school vii

CHAPTER 2

Electindo.comPHYSICS FOR JUNIOR HIGH SCHOOL VII

TEMPERATURE AND ITS MEASUREMENT

MEASUREMENT TOOLSTo determine whether an object hot or not, we can use our fingers, but they can not be used for determining the heat level of an object constantly. The appropriate tool to measure the temperature is thermometer.


TEMPERATURE

DEFINITIONWhat would you feel if you put your fingers into cold water ? Yes, of course, the cold water must taste cold. That sense of cold could be considered as the measurement of an object. A cold object has lower temperature than the hot object. Hence, it could be concluded that temperature is the heat level of an object or heat quantity of an object


TEMPERATURE

a. Celsius Scale

Celsius scale was determined by a physicist from Sweden, Andreas Celsius (1701 – 1744). Celsius temperature scale uses unit “Celsius degree” (°C)

b. Fahrenheit Scale

The freezing point in Fahrenheit scale is 32 °F and the boiling point is 212 °F. The distance between the two points is divided into 180 scales, Fahrenheit scale.

c. Reaumur Scale

in Reaumur scale, the freezing point has been fixed on 0 °R and the boiling point is 80 °R. The distance between the two points is divided into 80 scales.

d. Kelvin Scale

Kelvin scale was fixed by A physicist from England, Lord Kelvin. Its unit is Kelvin (K). In Kelvin scale, there is no negative scale, because the freezing point has been fixed on 273 K, and the boiling point fixed on 373 K. It means that 0 K is –273 °C.

THE TEMPERATURE SCALE AND ITS RATIO


TEMPERATURE

The scale ratio of Celsius thermometer, Reaumur thermometer, and Fahrenheit thermometer could be stated as follows :C : R : F = 100 : 80 : 180C : R : F = 5 : 4 : 9By looking at the fixed freezing 0ºC = 0ºR = 32ºF, the connection of C, F, R then could be stated as follows :tº C = tºRtº C = (tºF – 32)tº C = (tºF – 32)The scale connection between Celsius and Kelvin :t K = tºC + 273 K


KINDS OF THERMOMETER

1) Solid Substance Thermometer

It commonly uses soft platinum wire that is twisted on the mica and then put in a heat resisting silver tube.

example : platinum thermometer

KINDS OF THERMOMETER BASED ON THEIR CONTAINING SUBSTANCE

Platinum Thermometer


2) Liquid substance Thermometer

It is created based on the volume alteration. The used liquid are generally mercury or alcohol.

Example : Fahrenheit, Celsius, and Reaumur Thermometer



3) Gas substance Thermometer

It works with principle of the effect of temperature to the pressure. The design of this thermometer is the same with nanometer. At first, The U-shaped pipe containing mercury has balanced surface. If one of its end surface connected to a room containing pressured gas, there will be a difference on its end surface.Example: gas thermometer at constant gas volume



KINDS OF THERMOMETER BASED ON THEIR USE


1) Laboratorium ThermometerIt is commonly used for an experiment in the laboratory

2) Clinical ThermometerIt is particularly used for measuring the body temperature. This type of thermometer is generally used in medical check-up and its limit of scale is 34-42 0C.


1) Celsius Thermometer

KINDS OF THERMOMETER BASED ON THEIR CREATOR


2) Fahrenheit Thermometer


3) Reaumur Thermometer


4) Kelvin Thermometer


1) Clinical Thermometer

KINDS OF THERMOMETER BASED ON THEIR FUNCTION


2) Room Thermometer 3) Maximal-minimal Thermometer


4) Digital Thermometer

KINDS OF THERMOMETER BASED ON THEIR FUNCTION


5. Thermokepol


THANK YOU

chapter 2 electindo.com physics for junior high school vii

Documents

celsius temperature

reaumur scale

fahrenheit thermometer

scale connection

celsius scalecelsius

gas thermometer

negative scale

kelvin scalekelvin scale