Temperature is an important idea in science. It tells us how hot or cold something is. There are three main temperature scales: Celsius (°C), Fahrenheit (°F), and Kelvin (K). Knowing the differences between them is important, especially for students in Year 7, as it helps us understand heat and temperature better.

Celsius (°C)

• What it is: The Celsius scale is all about water. It sets 0 °C as the freezing point of water and 100 °C as the boiling point.
• Where it's used: This scale is popular worldwide, especially in science and in many countries, like Sweden.
• Key points:
  • Water freezes at: 0 °C
  • Water boils at: 100 °C
  • The range from freezing to boiling is 100 degrees.

Fahrenheit (°F)

• What it is: The Fahrenheit scale is mainly used in the United States. Here, water freezes at 32 °F and boils at 212 °F.
• Where it's used: This scale isn’t often used in science but is common in daily life in the U.S.
• Key points:
  • Water freezes at: 32 °F
  • Water boils at: 212 °F
  • The range from freezing to boiling is 180 degrees.

Kelvin (K)

• What it is: The Kelvin scale is a scientific temperature scale. It begins at absolute zero, which is 0 K. At this point, nothing moves at all.
• Where it's used: This scale is important for scientists, especially in studies about heat and energy.
• Key points:
  • Absolute zero: 0 K (which is -273.15 °C)
  • Water freezes at: 273.15 K
  • Water boils at: 373.15 K
  • The size of the degrees is the same as Celsius—changing by 1 K is like changing by 1 °C.

How to Change Between Scales

Here are some simple formulas to help you convert between these temperature scales:

1. Celsius to Fahrenheit:
   °F = (°C × 9/5) + 32

2. Fahrenheit to Celsius:
   °C = (°F - 32) × 5/9

3. Celsius to Kelvin:
   K = °C + 273.15

4. Kelvin to Celsius:
   °C = K - 273.15

5. Fahrenheit to Kelvin:
   K = (°F - 32) × 5/9 + 273.15

6. Kelvin to Fahrenheit:
   °F = (K - 273.15) × 9/5 + 32

Summary of Differences

| Scale | Freezing Point | Boiling Point | Common Usage | |------------|----------------|---------------|------------------| | Celsius | 0 °C | 100 °C | Used worldwide | | Fahrenheit | 32 °F | 212 °F | Mainly in the USA | | Kelvin | 273.15 K | 373.15 K | Used in science |

Knowing these temperature scales is very helpful. It allows us to use this knowledge in science and in our everyday lives.