Plants are living things, just like humans and animals. But unlike us, they can make their own food through a process called photosynthesis, using sunlight, water, and carbon dioxide from the air. Photosynthesis is not only how plants grow; it’s also one of the most important processes on Earth.
What plants need to grow
Plants require several key ingredients:
Plant need: Purpose
Sunlight: Provides energy for photosynthesis.
Water: Carries nutrients through the plant.
Carbon dioxide: Gas from the air used to make food.
Nutrients: Minerals in the soil that support growth.
How the parts of a plant work together
Each part of the plant has a job:
Roots absorb water and nutrients and anchor the plant.
Stems transport water and food.
Leaves collect sunlight and take in carbon dioxide.
Flowers produce seeds to make new plants.
What Is photosynthesis?
Photosynthesis is the process that allows plants to create their own food.
Simple Formula
Sunlight + Water + Carbon Dioxide → Glucose + Oxygen
Plants use glucose as energy to grow and release oxygen for us to breathe.
Why are leaves green?
Leaves are green because they contain chlorophyll, a pigment that captures sunlight.
Chlorophyll lives inside chloroplasts, which act like tiny solar panels inside the leaf.
Why photosynthesis matters
Photosynthesis is essential because it:
Provides oxygen needed by people and animals.
Creates food that starts the entire food chain.
Removes carbon dioxide, helping balance Earth’s atmosphere.
Supports ecosystems around the world.
Without plants, life on Earth could not survive.
Hands-on experiment
Experiment: Do Plants Produce Oxygen?
This experiment helps students see oxygen production during photosynthesis.
Materials
A clear glass or jar
A small fresh leaf from a green plant (or a spinach leaf)
Water
A sunny window or lamp
Procedure
Fill the glass with water.
Place the leaf completely underwater—use a small rock or spoon to keep it submerged.
Put the glass in bright sunlight.
Watch closely over the next 1–2 hours.
What you’ll see
Tiny bubbles will form on the surface of the leaf.
Those bubbles are oxygen being released during photosynthesis!
Why it happens
As the leaf uses sunlight to make food, it produces oxygen, which escapes into the water as bubbles.
Questions to think about
What would happen if this experiment was done in the dark?
Which leaves produce more oxygen, large ones or small ones?
Why is oxygen important to humans?
Photosynthesis worksheet
Try this fill in the blanks worksheet to test your photosynthesis knowledge.
Discussion questions for students
How do plants support life in every ecosystem?
What would happen if Earth had fewer trees?
Why do scientists say plants are Earth’s “oxygen factories”?
Key takeaway
Plants are remarkable producers that make food and oxygen for the whole planet.
Understanding photosynthesis helps us understand why protecting plants and forests is so important.
