How to measure two temperatures in Weather and Climate – Class 7 Science Experiment

Chapter Name: Weather and Climate

Activity Name: How to measure two temperatures in Weather and Climate

Activity Description:

Required Items:

1. Maximum Minimum Thermometer (MMT)
2. Magnet (for resetting the indicators)

Step by Step Procedure:

1. Take a Maximum Minimum Thermometer (MMT) from your school laboratory.
2. Examine the MMT: The thermometer consists of two cylindrical bulbs, A and B, connected through a U-shaped tube. Bulb A contains alcohol, while bulb B contains mercury. There are two indicators, I1 and I2, that move with the mercury within the U-tube.
3. Understanding the Principle: When the temperature increases, the alcohol in bulb A expands, causing the mercury in the U-tube to move towards bulb B, and indicator I1 moves up, indicating the maximum temperature of the day. On the other hand, if the temperature decreases, the alcohol in bulb A contracts, causing the mercury in the U-tube to move towards bulb A, and indicator I2 moves up, indicating the minimum temperature of the day.
4. Taking Readings: Place the MMT in the desired location where you want to measure the temperatures. Leave it there for a specific period, preferably 24 hours, to capture the maximum and minimum temperatures.
5. Record the Readings: After the designated time, observe the positions of indicators I1 and I2. Note down their respective positions on the scale. The positions will correspond to the maximum and minimum temperatures experienced during the recording period.
6. Resetting the Indicators: To reset the indicators I1 and I2 to their original positions, use a magnet. Move the magnet along the glass surface of the MMT to bring the indicators back to the starting point.

Experiment Observations:

1. The indicator I1 will show the highest temperature recorded during the time period.
2. The indicator I2 will show the lowest temperature recorded during the time period.

Precautions:

1. Handle the MMT with care, as it contains delicate glass components.
2. Keep the MMT away from direct heat sources or extreme temperatures during the recording period to avoid inaccurate readings.
3. Ensure the MMT is placed in an area with good air circulation and not obstructed by any objects.
4. Use a magnet gently to reset the indicators, avoiding any force that could damage the thermometer.

Lesson Learnt from Experiment:

The experiment demonstrates how a Maximum Minimum Thermometer (MMT) can be used to measure the highest and lowest temperatures experienced at a particular location over a period of time. The MMT is a useful tool for monitoring temperature variations and understanding the climatic conditions of a region.