National Agricultural Literacy Curriculum Matrix


Photosynthesis and You

Grade Level(s)

K - 2

Estimated Time

45 minutes plus observation time for 2 weeks


In this lesson, students will learn about the process by which plants make their own food. Students will understand how photosynthesis provides the food they eat.


For the teacher:

  • Fun With the Plant Nutrient Team student activity book

For the class experiment:

  • Three identical plants: One planted in potting soil, two planted in sand
  • One heavy, brown paper bag

For each student:

Essential Files (maps, charts, pictures, or documents)


photosynthesis: process by which plants use sunlight to make food from carbon dioxide and water

Background Agricultural Connections

This lesson is part of the Fun with the Plant Nutrient Team series which were written to help children better understand what the soil needs to be healthy in order to provide us with healthy foods. The lessons encourage students to think for themselves, ask questions, and learn problem-solving skills while learning the specific content needed to better understand the world in which they live. The lessons include:

Photosynthesis is the process by which plants and some algae and bacteria capture sunlight energy to make their own food.

The inputs for photosynthesis are sunlight, carbon dioxide, and water. The outputs are oxygen and carbohydrates in the form of sugars or starch.

People would not have food to eat if it weren’t for photosynthesis. Plants need the process to make their food, and people and other organisms depend on consuming plants or other organisms that eat plants. Plants and animals are interdependent; plants need the carbon dioxide that animals release during respiration and animals need the oxygen released by plants during the process of photosynthesis.

Plant leaves are the main site of photosynthesis. The chemical chlorophyll allows special cell structures called chloroplasts to absorb light energy. Carbon dioxide passes through the stomata on the underside of the leaves and moves to the cells where energy from the sun has been trapped and stored. Water is absorbed by the root hairs and transported up the stem. Through a chemical reaction, water and carbon dioxide are converted into carbohydrates that are used by the plant for energy and growth. Oxygen is then released from the plant into the atmosphere.

Interest Approach – Engagement

  1. Ask students what benefits we receive from the sun. Allow time for students to offer their ideas. Recognize that sun provides light and warmth to the earth. Point out that the sun is necessary for plants to grow.
  2. Ask students why plants are important. Allow students to answer the question and provide further guiding questions to help them realize that some of the food we eat comes from plants. For older students, point out that meat and milk (provided by animals) is also dependent on plants because the animals eat plants to grow and be healthy. Plants such as cotton provide fabric for clothing and trees provide lumber to build houses and other buildings.
  3. Inform students that they will be learning about photosynthesis, a process plants use to gain energy from the sun. This process is important because it is necessary to grow the food we eat.


Have students turn to page six in their Fun With The Plant Nutrient Team student activity book. Explain that they will be carrying out this experiment as a class.

Explain that plants A, B, and C are all the same types of plants and are the same age. Note: tomato seedlings work well for this experiment. The class will note their observations of the three plants on days 1, 4, 7, 11, and 14 on page six.

  1. Show students that Plant A is planted in sand and will be watered with distilled water. Explain that distilled water has been filtered so it does not contain any minerals or nutrients. Plant A will be set in a place where it receives sunlight for most of the day.
  2. Show students that Plant B is planted in potting soil that contains the important nutrients for plant growth. Plant B will be watered with tap water and will be set in a place where it receives sunlight for most of the day. Explain that tap water has been treated so it is safe for people to drink and may also contain some minerals.
  3. Show students that Plant C is planted in sand and will be watered with tap water. Place Plant C inside a heavy brown paper bag so it does not receive sunlight.
  4. Ask students to predict which plant will be the healthiest at the end of the experiment and why. Tally votes on the board and make a bar graph of class predictions.
  5. Give all three plants the same amount of water on the same days as needed.
  6. Allow students 5-10 minutes to observe the plants and write down their observations on days 1, 4, 7, 11, and 14. Older students can write down notes with descriptive observations while younger students can use the smiley faces on page six.
  7. On day 14 of the experiment, compare the results with the class predictions. What plant is the healthiest and why? What plant did not do well and why? Discuss these questions and answers as a class.
  8. Explain that Plant C did not get sunlight and therefore, was not able to carry out photosynthesis to make its own food. When a plant cannot make its own food, it doesn’t have energy to carry out life processes and it will become sick or die. Plant C was also planted in sand, which does not contain the nutrients that are important for plants to survive.
  9. Explain that Plant A was planted in sand, which does not contain the nutrients that are important for plants to survive. It was also watered with distilled water, which doesn’t have any nutrients. For these reasons, plant A didn’t grow much and wasn’t very healthy at the end of the experiment.
  10. Explain that Plant B is likely the healthiest because during the experiment it received everything a plant needs to grow and be healthy. Plant B received sunlight, water, and potting soil that contained important nutrients for plant growth.
  11. Ask students why it is important to have healthy plants that can carry out the process of photosynthesis. Explain that we depend on photosynthesis for plants to make the food that we eat. Use a bowl of cereal and milk as an example. Where did the wheat, rice, or corn in the cereal come from? (plants) Where did the milk come from? (a cow) What do cows eat? (plants/grass)

Worksheet Procedure

  1. Provide the student handout, Photosynthesis and You, to older students and read aloud as a class. For younger students, summarize the main points of the reading to provide background information for the drawing activity.
  2. Lead students through the photosynthesis drawing activity step by step.

Concept Elaboration and Evaluation:

After conducting these activities, review and summarize the following key concepts:

  • Plants provide food for us to eat.
  • Plants rely on the sun to obtain energy to grow. The process is called photosynthesis.
  • The sun is a natural resource that farmers use to grow and produce the food we eat.

Enriching Activities

Suggested Companion Resources

Agricultural Literacy Outcomes

Plants and Animals for Food, Fiber & Energy

  • Explain how farmers work with the lifecycle of plants and animals (planting/breeding) to harvest a crop (T2.K-2.a)
  • Identify the importance of natural resources (e.g., sun, soil, water, minerals) in farming (T2.K-2.e)

Education Content Standards


1-LS1: From Molecules to Organisms: Structures and Processes

  • 1-LS1-1
    Use materials to design a solution to a human problem by mimicking how plants and/or animals use their external parts to help them survive, grow, and meet their needs.

2-LS2: Ecosystems: Interactions, Energy, and Dynamics

  • 2-LS2-1
    Plan and conduct an investigation to determine if plants need sunlight and water to grow.

K-2-ETS1: Engineering Design

  • K-2-ETS1-1
    Ask questions, make observations, and gather information about a situation people want to change to define a simple problem that can be solved through the development of a new or improved object or tool.

K-ESS3: Earth and Human Activity

  • K-ESS3-1
    Use a model to represent the relationship between the needs of different plants or animals (including humans) and the places they live.

K-LS1: From Molecules to Organisms: Structures and Processes

  • K-LS1-1
    Use observations to describe patterns of what plants and animals (including humans) need to survive.

Common Core Connections

Reading: Anchor Standards

    Read closely to determine what the text says explicitly and to make logical inferences from it; cite specific textual evidence when writing or speaking to support conclusions drawn from the text.
    Integrate and evaluate content presented in diverse media and formats, including visually and quantitatively, as well as in words.

Speaking and Listening: Anchor Standards

    Prepare for and participate effectively in a range of conversations and collaborations with diverse partners, building on others’ ideas and expressing their own clearly and persuasively.
    Make strategic use of digital media and visual displays of data to express information and enhance understanding of presentations.

Writing: Anchor Standards

    Write informative/explanatory texts to examine and convey complex ideas and information clearly and accurately through the effective selection, organization, and analysis of content.
    Gather relevant information from multiple print and digital sources, assess the credibility and accuracy of each source, and integrate the information while avoiding plagiarism.


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