Study Notes
Temperature scales are systems used to measure temperature, with different scales based on various reference points and principles.
- Thermometer — an instrument that measures temperature by using physical properties that change with temperature. Example: A liquid-in-glass thermometer uses the expansion of mercury to measure temperature.
- Calibration — the process of setting a thermometer to known reference points to ensure accurate measurements. Example: Using the boiling and melting points of water (0°C and 100°C) for calibration.
- Kelvin Scale — a thermodynamic temperature scale that starts at absolute zero, where no molecular motion occurs. Example: 0 K is equivalent to -273.15°C.
- Absolute Zero — the lowest possible temperature where all molecular motion stops. Example: 0 K or -273.15°C.
- Celsius Scale — a temperature scale based on the freezing and boiling points of water. Example: Water freezes at 0°C and boils at 100°C.
Exam Tips
Key Definitions to Remember
- Thermometer: An instrument for measuring temperature.
- Calibration: Setting a thermometer to known reference points.
- Absolute Zero: The lowest possible temperature, 0 K.
- Kelvin Scale: A temperature scale starting at absolute zero.
Common Confusions
- Confusing Celsius and Kelvin scales.
- Misunderstanding absolute zero as achievable in practice.
Typical Exam Questions
- What is absolute zero? Absolute zero is 0 K or -273.15°C, the lowest possible temperature.
- How do you convert Celsius to Kelvin? Add 273.15 to the Celsius temperature.
- Why is the Kelvin scale used in thermodynamics? Because it is an absolute scale not tied to any specific substance.
What Examiners Usually Test
- Understanding of different temperature scales.
- Ability to convert between Celsius and Kelvin.
- Knowledge of absolute zero and its significance.