PHOTOSYNTHESIS
Suggested Grade: 3
Driving Questions
Grade 3
- Why do we need the sun?
- What is photosynthesis
Learning Intentions
- I know how important the sun and green plants are to all life on earth.
- I understand that the sun’s energy is the basis of all of the energy that all living things on earth use (plant, or animal)
Materials
- Green and White Asparagus – if you can`t find any white asparagus then use a picture
Lesson
- Present green and white asparagus to class. Have students compare the two – taste, smell, feel, look. On a sheet of paper they can draw and color each and record their comparisons underneath.
- As a class discuss the differences and brainstorm why one is white and the other is green (one can photosynthesize (green) the other cannot (no pigment)).
- Discuss photosynthesis.
Click here to download a printable version of this lesson
Discussion
In the leaves of a plant is a substance called chlorophyll. Chlorophyll is a pigment. Chlorophyll is similar to hemoglobin which is the pigment that makes blood red. It is the pigment chlorophyll that traps the energy from the sun. Chlorophyll makes leaves green.Plants with red or some other color generally contain colored pigments that mask the green. If the pigment is water soluble, you can put the colored leaf in boiling water and the pigment will be extracted. This is how people used to make colors to dye fabric.
Almost all plants needs the sun in order to survive. They use the energy from the sun’s light to turn carbon dioxide and water into sugar and oxygen. The sugar is used by the plant to grow. The oxygen is released and can be used by people and animals. All people and animals, even tiny microbes need oxygen. The process of photosynthesis is the most important process that occurs on earth for us all.
Plants take carbon dioxide from the air and “breathe out” oxygen.
We breathe in oxygen and breathe out carbon dioxide.
Plants additional facts for older children:
Also need minerals from the soil to grow. …
Plants need large amounts of nitrogen, phosphorus and potassium.
Photosynthesis can be represented using a chemical equation:
Carbon dioxide + Water ——>Sugar + Oxygen
Sunlight energy
What kinds of physical factors affects photosynthesis?
- Temperature
- Day length (amount of light)
- Soil composition for land plants
- Water composition for aquatic plants (marine and estuarine or fresh water)
Some study question :
- What time of the year do plants grow the best: Why / what do you think happens to plants and photosynthes if we do have enough rain: too much rain?