ICSE Class 10 Answered

Experiment: Potometer Method

Potometer is a device that measures the rate of water intake by a plant which is almost equal to the water lost through transpiration.

Procedure

• Fix a cut shoot of a leafy plant in the photometer and fill the photometer with water.
• Immerse the distal end of the photometer in a beaker containing coloured water.
• When the coloured water rises in the horizontal arm of the apparatus, remove the tube from the beaker and allow air to enter it.

Observation: Air bubbles move through the horizontal arm.

Inference: Water loss during transpiration sets up the suction force which pulls the water from the beaker and bubbles move along in the capillary.