---
title: "Plants Grow from Air & Water"
description: "Support an argument that plants get the materials they need for growth chiefly from air and water, not from the soil"
canonical: https://lightmysky.com/learn/science/plants-grow-from-air-and-water-mt_3-ii06P4YS
source: https://lightmysky.com/learn/science/plants-grow-from-air-and-water-mt_3-ii06P4YS.md
retrieved: 2026-10-19
---

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# Plants Grow from Air & Water

Support an argument that plants get the materials they need for growth chiefly from air and water, not from the soil

Subject: Science · Area: Organisms & Life Processes · Ages 10 to 11
Page: https://lightmysky.com/learn/science/plants-grow-from-air-and-water-mt_3-ii06P4YS

## Ready when they can

- Explain that plants take in carbon dioxide from air and water from soil to make food (photosynthesis)
- Argue that most of a plant's mass comes from air (CO₂) and water, not soil minerals
- Describe a simple investigation showing soil mass barely changes while a plant grows significantly

## Lesson: Plants Build Themselves from Air and Water

It looks like a plant grows by eating soil, the same way you grow by eating food. That is not quite right. A plant makes almost all of its own body out of air and water.

*(drawing: Air and water make up almost all of a plant's mass. Soil gives only a tiny share.)*

**Example.** A scientist planted a small tree in a pot and weighed the soil first. He watered the tree for five years and let it grow. The tree became much bigger and heavier. But when he weighed the soil again, it had lost only a little weight, not nearly enough to explain the tree's new size.

**Tip.** Photosynthesis is the word for how a plant makes its own food. It takes in carbon dioxide from the air and water from its roots, then uses sunlight to turn them into sugar. That sugar becomes new leaves, stems, and roots.

**Recap.** A plant's body is mostly built from air and water, not from soil.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Water Transport in Plants](https://lightmysky.com/learn/science/water-transport-in-plants-mt_GF6L7J4MNN)
- [What Plants Need to Thrive](https://lightmysky.com/learn/science/what-plants-need-to-thrive-mt_lutxvMlkwS)

## Opens up

- [Energy from Food & the Sun](https://lightmysky.com/learn/science/energy-from-food-and-the-sun-mt_PYPs2yD2sn)