Hey kids, here's a small after-school exercise. Have fun!
 

Have you observed the leaves of some trees and plants in your locality? Their leaves are usually green in colour and flat in shape. You will find that leaves of mango, papaya, banana and guava have the green colour in common. Although the leaves have different shapes, they are all green in colour. Here is an activity that explains the process of Photosynthesis that enables plants to get the green colour.
 

Material required:

• 2 small flowerpots
• Garden soil for filling the pots
• 2 small plants or any seasonal flower or vegetable
  
  

Take two flowerpots, mark them as X and Y and fill them with garden soil. Add some manure in both the pots. Now take two saplings and plant them in the pots X and Y. After watering both the pots, keep the pot X outside your house, ensuring enough sunlight. Keep the pot Y in a shaded area. Water the plants every day. Observe them after a day or two. You will find that the one kept in sunlight grows in size after a week with leaves green and healthy, whereas the other yellows down. You can also take a shoot of a Money plant and put it in a bottle of water. After a week you will see that roots have grown on the submerged end of the plant.
 

Sunlight is a must

So, we know that sunlight is essential for the survival and growth of all plants. Though plants need fresh air, water and nutrients to grow, sunlight plays the most important role in preparing their nutrition. And leaves do this process of photosynthesis.  

Leaves are green because they have a green pigment called chlorophyll. They have small pores called stomata. Carbon dioxide (CO2) is absorbed into these leaves through the stomata. And sunlight gives energy to the plant to convert water and CO2 into sugar and starch, which is the food of the plant. Leaves also have small disk-like structures called chloroplast and the process of photosynthesis takes place inside these chloroplasts. Some plants like Cactus can survive even in dry regions because they can store their food for months.