Photosynthesis for Kids: How Plants Make Their Own Food

By Eduminate

Pastel desk scene with a potted plant, a jar with a leaf, a watering can and a lamp on a mint green background.

Photosynthesis for kids starts with one simple idea: plants make their own food from light, water and air. This guide covers the definition, the ingredients, the steps in order, a leaf diagram to label, two easy experiments and ways to teach it.

Photosynthesis for kids

Most living things cannot make food from nothing. Animals eat plants or eat other animals. Plants are different. They build their own food inside their leaves, and the process they use is called photosynthesis.

The word comes from two Greek parts. “Photo” means light and “synthesis” means putting together. So photosynthesis means putting things together with light. That is a good way to introduce the word, because it tells students what the process does before they learn any details.

Plants are not the only living things that do this. Algae and some kinds of bacteria also use light to make food. In a classroom, though, the focus is nearly always on green plants, so this guide does the same.

Photosynthesis definition for kids

If a student asks what is photosynthesis for kids, here is a definition that fits on an index card:

Photosynthesis is the process plants use to turn light energy, water and carbon dioxide into sugar and oxygen.

The sugar is the plant’s food. The oxygen is released into the air. Carbon dioxide is a gas found in air, and it is one of the gases people and animals breathe out.

Some students like a shorter version first: plants use sunlight to make food. You can add the details one layer at a time.

What plants need for photosynthesis

A plant needs three ingredients. Without all three, it cannot do photosynthesis.

Light. Usually this is sunlight. The light supplies the energy that powers the whole process. A bright lamp can also work for a plant that grows indoors.
Water. Roots take in water from the soil. The water travels up through the stem to the leaves.
Carbon dioxide. The leaves take this gas in from the air through tiny openings.

Notice that soil is not on the list. Soil gives a plant water and small amounts of minerals, but the plant’s food is not made from soil. This is a common surprise, and it is worth saying out loud. The sugar a plant makes is built mostly from carbon dioxide and water.

What plants make

Photosynthesis has two products:

Glucose. This is a type of sugar. The plant uses it for energy and to grow new leaves, stems, roots and flowers. Some of it is stored, often as starch, for later.
Oxygen. This gas leaves the plant through the same tiny openings that let carbon dioxide in.

Older students can see the whole process as a word equation:

carbon dioxide + water + light energy → glucose + oxygen

The chemical version is 6CO2 + 6H2O + light energy → C6H12O6 + 6O2. Younger students do not need it. For middle school, it helps to point out that the same atoms appear on both sides, only rearranged into new substances.

Steps of photosynthesis for kids

The steps of photosynthesis for kids can be told as a short sequence. Here is one way to put it in order:

The roots take in water from the soil.
The water moves up the stem to the leaves.
The leaves take in carbon dioxide from the air.
Green parts inside the leaf catch light energy from the sun.
The plant uses that energy to turn water and carbon dioxide into glucose and oxygen.
The oxygen goes out into the air, and the glucose is used or stored.

Older students can learn that the chemistry happens in two stages. In the first stage, the leaf captures light energy. In the second, it uses that energy to build sugar from carbon dioxide. Both stages take place inside chloroplasts, the tiny structures in leaf cells. Naming the two stages is enough for upper elementary. Middle school can add the proper names, the light-dependent reactions and the Calvin cycle.

Photosynthesis diagram for kids

A diagram makes the process easier to remember because students can see where each ingredient goes in and where each product comes out. A photosynthesis diagram for kids usually shows one plant with arrows. Here is a plan for drawing your own on the board or on paper.

Draw a plant with roots, a stem and several leaves.
Draw a sun shape above it and arrows pointing down to the leaves. Label the arrows “light energy.”
Draw an arrow from the soil into the roots and label it “water.”
Draw an arrow from the air into a leaf and label it “carbon dioxide.”
Draw an arrow leaving the leaf and label it “oxygen.”
Write “glucose” next to the leaf or inside it to show where the food is made.

Use a plain circle for the sun, with no face. A colored pencil for each arrow helps: yellow for light, blue for water, and so on. Inputs arrow in, outputs arrow out. If students always draw inputs on one side and outputs on the other, the diagram stays easy to read.

Parts of the leaf to label

A closer view of one leaf adds more detail:

Chlorophyll: the green substance in leaf cells that captures light. It is the reason most leaves look green.
Chloroplasts: the small parts inside a leaf cell that hold the chlorophyll. This is where photosynthesis takes place.
Stomata: tiny openings, mostly on the underside of a leaf, that let carbon dioxide in and oxygen out. One opening is a stoma.
Veins: thin tubes that bring water into the leaf and carry sugar away to the rest of the plant.

Why is photosynthesis important

Why is photosynthesis important? There are a few clear reasons, and each one connects to something students already know.

It feeds the plant. The glucose gives the plant the energy and material it needs to grow.
It feeds other living things. Plants sit at the start of most food chains. When an animal eats a plant, it gets some of the energy that the plant stored. Our post on the food chain shows how that energy passes from one link to the next.
It adds oxygen to the air. Plants are an important source of the oxygen that people and animals breathe. Algae in oceans and lakes also add oxygen to the air.
It uses carbon dioxide. Photosynthesis takes this gas out of the air while it builds sugar.

The word producer is useful here. A producer is a living thing that makes its own food. Plants are producers. Animals are consumers because they get their food by eating something else.

Photosynthesis and respiration

Students sometimes think plants breathe in carbon dioxide and breathe out oxygen, while animals do the opposite, and that is the whole story. It is a decent start, but there is one more piece. Plants also use oxygen.

All living things, including plants, release the energy stored in sugar through a process called cellular respiration. It uses oxygen and gives off carbon dioxide. Plants do this all day and all night. Photosynthesis needs light, so it only runs when light is available. In bright light, a plant usually makes more oxygen than it uses, so the net result is oxygen going out into the air.

A simple way to say it: photosynthesis stores energy in sugar, and respiration releases that energy so the cells can use it.

Photosynthesis experiment for kids

Experiments make an invisible process visible. These two use ordinary materials and need very little setup. Both involve plants only.

Bubbles from a water plant

Water plants such as pondweed give off tiny bubbles of oxygen in bright light. Put a few stems in a large clear jar of water and set the jar in a sunny window or beside a bright lamp. Small bubbles collect on the leaves and stems. Those bubbles are oxygen. Students can set up a second jar in a dim spot to see whether anything changes.

Light and dark leaves

Cover part of one leaf on a healthy potted plant with a strip of dark paper held by a paper clip. Leave the plant in a bright place for several days with regular watering. Remove the paper and compare the covered strip with the rest of the leaf. Students record what they see and write a sentence connecting the result to what a leaf needs. The covered part has had less light, and the leaf shows a difference.

Whichever photosynthesis experiment for kids you pick, ask students to write a prediction first. After the activity, they write what happened and whether it matched. That routine is useful for any science investigation.

Photosynthesis facts for kids

These photosynthesis facts for kids work well as a warm-up, a quick quiz or an exit ticket:

Photosynthesis happens mostly in leaves, though other green parts of a plant can do it too.
Chlorophyll makes leaves look green.
Plants take in carbon dioxide and give out oxygen during photosynthesis.
Roots take in water, and the stem carries it up to the leaves.
In autumn, many leaves lose their green color because the chlorophyll breaks down. Yellow and orange colors that were hidden then show.
Stomata open and close, which lets the plant control what goes in and out.
A plant stores extra sugar, often as starch, in roots, stems, seeds and fruits.
Algae also do photosynthesis, even though they are not plants.

How to teach photosynthesis

Ingredient and product cards

Write each of the five items on its own card: light, water, carbon dioxide, glucose, oxygen. Students sort the cards into two piles, things a plant takes in and things a plant makes. Ask them to explain each choice aloud. Ask a follow-up: which card was the easiest to place, and which was the hardest?

Sentence frames

Give students a frame such as “A plant uses ___, ___ and ___ to make ___ and ___.” They fill in the blanks from memory, then check against the diagram. A second frame helps with purpose: “Photosynthesis is important because ___.”

Label and explain

Hand out a blank outline of a plant. Students label the roots, stem and leaf, add arrows for the inputs and outputs, and write a short caption. Older students can add the leaf parts and a word equation.

Link to other science topics

Photosynthesis connects naturally to other units. The water cycle explains where the water in the soil comes from. The food chain shows what happens to the energy next. The post on the states of matter helps with the idea that carbon dioxide and oxygen are gases that take up space even though we cannot see them.

Reading and practice material

Reading about plants gives students a chance to meet the vocabulary in context. Eduminate has several science reading packs that stay with plants and growing things.

The plant growth reading passages are a 64 page packet of ten science articles with 200 questions, for grades 5 to 8.
The growing vegetables passages are a 63 page set of ten science reading passages on seeds, garden tools, plant nutrition, beneficial insects and soil health, for grades 1 to 5.
The spring flowers passages are a 62 page set of ten texts on plant growth, pollination and seasonal blooms, with answer keys, for grades 1 to 5.
The elementary science reading pack is a 48 page packet with passages across ten STEM topics, including magnets, matter and ecosystems, with answer keys, for grades 2 to 5.
The cactus adaptations passages are a set of ten reading passages with a lesson plan and answer keys, for grades 2 to 8.
The carnivorous plants passages are 64 pages of ten reading passages covering insect traps and plant adaptations, for grades 2 to 6.

These packs are reading practice about plants and their surroundings. Use them alongside the hands-on work in this guide, not instead of it.

Frequently asked questions

Do plants make food at night?

Photosynthesis needs light, so it mostly stops when it is dark. Plants still do cellular respiration at night, which uses the sugar they stored during the day.

Where does a plant get the material to grow?

Most of the material comes from the carbon dioxide in the air and the water from the soil, which the plant turns into sugar. Soil adds minerals, but it is not the main building material.

What grade learns photosynthesis?

Many classrooms introduce the basic idea in elementary school and add the chemistry later. The reading packs above cover grades 1 to 8, so check the grade range on each product page.

Related resources

Plant growth reading comprehension passages, grades 5 to 8
Growing vegetables reading passages, grades 1 to 5
Spring flowers reading passages, grades 1 to 5
Elementary science reading comprehension passages, grades 2 to 5
Cactus adaptations reading comprehension passages, grades 2 to 8
Carnivorous plants reading comprehension passages, grades 2 to 6