# Temperature and Its Standard Units

**LESSON – TEMPERATURE **

TOPIC

** INTRODUCTION **

Heat is the cause, a rise in temperature is the effect.

When a substance is hot, the temperature is high and when the substance is less hot (cold), the temperature is lower.

Temperature can be measured with a thermometer in degree Celsius and degree Fahrenheit called unit.

The relationship between the two (2) units can be expressed as unit of one another

Thermometer is an device used to measure temperature of a body or an object.

For example, how hot or cold is water, food, iron, human body, etc.

**FEATURES OF A THERMOMETER **

The features of thermometer are as follows:

1. Scale – degree Celsius (ºC) and Fahrenheit (ºF)

2. Work liquid

3. Reference point

4. Bulb

**UNITS AND SYMBOLS OF TEMPERATURE SCALE **

There are two (2) units of measurement for temperature,

1. Degree Celsius (ºC)

2. Degree Fahrenheit (ºF)

**T****HE USES OF THERMOMETER **

Thermometers are used to measure temperature.

Below are the uses of thermometer,

1. It is used to measure the outdoor temperature.

2. It is used to measure body temperature – the doctor.

3. It is used to measure body temperature when someone is ill to determine if the person has a fever.

4. It is used to measure the temperature of an experiment.

5. It is used to measure the temperature of a cold room.

QUICK EVALUATIONAsk the pupils,

1. Define thermometer.

2. State the features of thermometer.

3. State the 2 units of measurement for temperature. With appropriate scales.

ASSIGNMENTSolve the following –

1. Divide 20 by 5, then multiply by 9, then add 32.

2. Divide 50 by 5, then multiply by 9, then add 32.

3. Divide 75 by 5, then multiply by 9, then add 32.

**CONVERSION OF CELSIUS TO FAHRENHEIT**

Remember the Hint,To convert Celsius (°C) to Fahrenheit (°F), follow the steps,

- divide the degree by 5

- then multiply by 9,

- now add 32

Working Example 1Convert 25° Celsius to Fahrenheit.

1st,the 25° by 5,

25° ÷ 5 = 5

2nd, multiply the result by 9,

5 × 9 = 45

3rd, add 32,

45 + 32 = 77° F

Summary, 25° ÷ 5 x 9 + 32 = 77° F

Working Example 2Convert 30º Celsius to Fahrenheit.

1st,the 30° by 5,

30° ÷ 5 = 6

2nd, multiply the result by 9,

6 × 9 = 54

3rd, add 32,

54 + 32 = 86° F

QUICK EVALUATIONConvert the following to Fahrenheit,

1. 20º

2. 15º

3. 56°

4. 23°

ASSIGNMENT1. Subtract 32 from 77, then multiply by 5, then divide by 9.

2. Subtract 32 from 86, then multiply by 5, then divide by 9.

**CONVERSION OF FAHRENHEIT TO CELSIUS**

Remember the Hint – To convert °F to °C, follow the steps,

1st, Subtract 32,

2nd, multiply by 5

3rd, then divide by 9.

Working Example 1Convert 77º Fahrenheit to degree Celsius.

1st, Subtract 32,77º — 32 = 45

2nd, multiply by 545 x 5 = 225

34rd, then divide by 9.225 ÷ 9 = 25 ºC

Working Example 2Convert 86º Fahrenheit to degree Celsius.

1st, Subtract 32,86º —32 = 54

2nd, multiply by 554 x 5 = 270

3rd, then divide by 9.

270 ÷ 9 = 30º C

QUICK EVALUATION

Convert the following to Celsius,

1. 68º

2. 59º

3. 36

4. 40