Grade 3 Science Experiments Lesson 2

Grade 3 Science: Lesson 2 – Plants And Their Parts

Experiments

Three experiments were done and the results were displayed in the class. Students were called in groups and detailed explanation was given to them.

1.     To show that sunlight is necessary for photosynthesis: Seeds of Moong, Fenugreek and Sesame were planted in two pots. One pot was kept in the cupboard (dark) while the other was near the window (sunlight).

Observation: Moong was the first to grow. The plant in the dark was yellow in colour as it could not prepare its own food and there was no photosynthesis. The plan could not synthesize cholorophyll.

The plant near the window got sunlight and grew well, and was green. Photosynthesis and synthesis of chlorophyll took place.

 

2.     To show that stem conducts water to all parts of the plant: Two stems with Rajnigandha flowers were placed in two bottles containing water. Red ink was added to one bottle.

Observation: The flowers kept in water containing red ink turned pink in a few hours. This shows that the water was conducted by the stem to all parts of the plant.

 

3.     To show that leaves give out excess of water during respiration: A plastic bag was tied on a branch of a potted plant with leaves. An empty bag was hung on another branch.

Observation: After a few hours, water droplets formed in the bag tied around leaves, while the other bag was empty and dry. This proves that water vapour is a by-product of respiration, given out through stomata on the leaves.