18th August 2020

# JSS 2 : PHYSICS : WEEK 4

NEW APPROACH

WEEK/TERM: THIRD TERM/WEEK 4

DATE: 05.05.2020

CLASS: J.S.S 1

SUBJECT: PHYSICS

TOPIC: THE CONCEPT OF TEMPERATURE AND HEAT

REFERENCE: ESSENTIAL PHYSICS FOR SENIOR SECONDARY SCHOOL

BRIEF EXPLANATION: Heat is a concept of physics that deals with the study of relative motion of fluid from one body to another. Temperature is sometimes mistakenly used to mean heat. Heat and temperature have different meanings entirely.

Heat measures the change in total internal energy or quantity of matter in a body while temperature is the degree of hotness and coldness of a body.

Notes for students (lesson one)

Heat is a form of energy due to a difference in temperature. Heat energy is a form of energy that flows from a substance at a higher temperature to the substance at a lower temperature thereby raising the temperature of the later and lowering that of the former substance provided that the volume remains constant.

Heat is measured in JOULES(J) and it is named after James Prescott Joules (1819-1889).

Temperature

Temperature is the degree of hotness and coldness of a body. The units of measurement of temperature are Fahrenheit, Celsius, kelvin and Rankine. A thermometer is an instrument used in measuring temperature.

Qualities of a thermometer

1. Construction
2. Calibration
3. Sensitivity

Types of thermometer

1. Constant volume gas thermometer
2. Liquid in glass thermometer
3. Resistance thermometer
5. Thermo-electric thermometer (pyrometer)
6. Thermocouple

Celsius scale = 0 – 100o

Kelvin scale = 273k – 373k

Fahrenheit = 32

Lesson two

Differences between heat and temperature

 Heat Temperature 1 It is a measure of the quantity of matter in a body It is the measure of hotness or coldness 2 It is a derived quantity A fundamental quantity 3 Not determined directly by an instrument Determined directly by a thermometer 4 Measured in joules Measures in o Celsius, Fahrenheit 5 It takes place due to temperature difference It occurs due to slight change in the state of a substance

EFFECTS OF HEAT

When heat is applied to a body, there would be changes in the physical properties of the body. These changes are:

1. Temperature changes (rise in temperature)
2. Expansion
3. Change of state
4. Vapourization
5. Contraction of the body
6. Chemical changes
7. Thermionic emission
8. Change in pressure of the body.

Exercises / Assignment

1. What is heat?
2. State five effects of heat on substance (SSCE1990)
3. Write in a tabular form, three differences between heat and temperature.
4. List 4 types of thermometer.
5. Write 2 qualities every thermometer must possess.
6. Why is water not used as a thermometric substance? (SSCE 1991)