The Real Ingredients: Air and Water
The real ingredients: air and water teaches Grade 5 students the surprising truth about photosynthesis — plants build their bodies primarily from two invisible or simple ingredients: carbon dioxide gas from the air and water from the ground. Roots absorb water; leaves take in CO₂. These two inputs — not soil — are the raw materials a plant uses to construct its stems, leaves, roots, and flowers. This lesson from Amplify Science (California) Grade 5, Chapter 2, directly challenges the common misconception that plants grow by consuming soil.
Key Concepts
If plants don't eat soil, what are they made of? They build their bodies using two invisible or simple ingredients found in their environment.
First, plants use their roots to absorb water from the ground. Second, they take in a gas called carbon dioxide from the air. These two materials—water and air—are the primary ingredients a plant uses to build its stems, leaves, and roots.
Common Questions
What are the two main ingredients plants use to build their bodies?
Carbon dioxide gas (CO₂) absorbed from the air through tiny pores in leaves, and water absorbed from the ground through roots.
How do plants absorb water?
Plant roots absorb water from the soil. The water travels upward through the plant's stem to leaves, where it is used in photosynthesis.
How do plants get carbon dioxide?
Plants absorb CO₂ through tiny pores called stomata in their leaves. CO₂ is a gas naturally present in air at about 0.04% concentration.
If soil isn't the main ingredient, why do plants need soil?
Soil provides small but important minerals and nutrients (like nitrogen, phosphorus, potassium) that act as vitamins. It also provides physical support and holds water near the roots. But it is not the source of the plant's bulk mass.
What does a plant do with the water and CO₂ it absorbs?
Using energy from sunlight, the plant combines water and CO₂ molecules to produce sugar through photosynthesis. The plant then uses this sugar to build its cells and structures.
What grade and chapter covers the real ingredients of plant growth?
Grade 5, Chapter 2 of Amplify Science (California): Why aren't the cecropia trees growing and thriving?