Effect of surface area, Humidity and wind speed on evaporation in Matter Around Us – Class 9 Science Experiment

Chapter Name: Matter Around Us

Activity Name: Effect of surface area, Humidity and wind speed on evaporation in Matter Around Us

Activity Description:

This experiment aims to investigate the factors that affect the rate of evaporation of water. Three different scenarios are tested: evaporation of water in a test tube, a china dish under a fan, and a china dish kept in a cupboard. The room temperature and the time taken for evaporation are recorded for each case. Additionally, the experiment suggests repeating the activity on a rainy day and recording observations.

Required Items:

1. Test tube
2. Three china dishes
3. Water
4. Fan
5. Cupboard

Step by Step Procedure:

1. Take 5ml of water in a test tube.
2. Take another 5ml of water in a china dish and place it under the fan.
3. Take 5ml of water in a different china dish and keep it inside the cupboard.
4. Record the room temperature.
5. Observe and record the time taken for evaporation of water in all three cases.
6. If possible, repeat the experiment on a rainy day and record observations.

Experiment Observations:

1. Record the room temperature and note its effect on the rate of evaporation in each case.
2. Measure and compare the time taken for water to evaporate from the test tube, china dish under the fan, and china dish in the cupboard.
3. Observe and record any differences in evaporation rates on a rainy day.

Precautions:

1. Ensure accurate measurements of water in each container.
2. Keep other external factors constant during the experiment.
3. Use the same fan speed throughout the experiment.
4. Take multiple readings for more reliable results.

Lesson Learnt from Experiment:

The experiment demonstrates that the rate of evaporation is affected by surface area, humidity, and wind speed. Evaporation is faster in the china dish due to its larger surface area compared to the test tube.

The presence of wind from the fan facilitates faster evaporation as it helps in carrying away the water vapor. On the other hand, keeping the china dish in the cupboard restricts air movement, leading to slower evaporation.