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Subject: Physics
Semester: 2
Period: 4
Week: 21
School Name:
Teacher’s Name:
Subject: Physics
Grade Level: Grade 10
Week & Period: Week 21, Period IV
Date:
Sub-topic: Thermometry – Types, Properties, and Calibration of Thermometers
Learning Objectives:
By the end of the lesson, learners should be able to:
- Describe different types of thermometers.
- Explain how thermometers work based on their properties.
- Identify calibration methods and interpret thermometer readings.
- Solve problems involving thermometer intervals and scale values.
Instructional Materials:
- Laboratory and clinical thermometers
- Thermocouple thermometer
- Gas thermometer
- Digital thermometer
- Ice and hot water baths
Anticipation (Warm-Up):
Ask: “Why do we use different thermometers for different tasks like cooking, medicine, and weather?”
Building Knowledge:
- Types of Thermometers:
- Liquid-in-glass (Mercury/Alcohol) – used for general laboratory and environmental temperatures.
- Clinical thermometer – measures human body temperature (35–42°C), narrow constriction prevents immediate mercury fall.
- Thermocouple thermometer – measures very high temperatures using voltage changes.
- Gas thermometer – based on pressure changes in a fixed volume gas.
- Digital thermometer – uses electronic sensors, fast and easy to read.
- Properties of Thermometric Substances:
- Expansion with temperature
- Sensitivity to small temperature changes
- Predictable and consistent response
- Non-volatility and non-reactivity
- Calibration:
- Using fixed points: ice point (0°C), steam point (100°C)
- Divide into equal intervals (e.g., 0–100 for Celsius)
- Scale: difference in degree markings between fixed points.
Solved Example:
If a thermometer has ice point at 5 mm and steam point at 55 mm, what is the temperature reading when the mercury level is at 30 mm?
Solution:
Activities:
- Observe and record temperatures with multiple thermometers.
- Compare clinical and lab thermometers in warm and cold baths.
- Demonstrate calibration steps using ice and steam.
Assessment:
- List 3 types of thermometers and their uses.
- A mercury thermometer reads 60 mm at steam point and 10 mm at ice point. If it reads 40 mm, what is the temperature?
Homework:
- Sketch and label a clinical and a lab thermometer. State 2 features of each.
- Why is alcohol sometimes preferred to mercury in thermometers?
Expanded Notes:
- Digital thermometers are safer and faster but require batteries.
- Calibration ensures consistent and accurate readings.
- Thermometric properties determine the suitability of substances.
Differentiation:
- Provide diagram sheets for labeling for visual learners.
- Use real thermometers for hands-on learners.
- Give slower learners extra practice on calibration calculations.
Teacher’s Reflection:
- Were students able to describe thermometer types confidently?
- Did they understand calibration processes?
- Should another session be held using digital vs analog devices?