Building a Solid Body
Building a solid body teaches Grade 5 students the remarkable conclusion of photosynthesis: plants use sugar (made from air and water) to construct their solid physical structures, including trunks, stems, and leaves. This explains how plants gain mass — the mass of air (carbon dioxide) and water is chemically converted into the mass of solid plant tissue. A massive tree trunk is literally made of transformed air and water molecules. This concept from Amplify Science (California) Grade 5, Chapter 2, completes the explanation of where plant mass comes from.
Key Concepts
The final result of this process is a solid plant body. The sugar produced from air and water is used to build the hard trunk of a tree or the soft stem of a flower.
This explains how a plant gains weight. The mass of the air and water is converted into the mass of the plant. The plant literally builds itself out of the air it breathes and the water it drinks.
Common Questions
How do plants build their solid structures?
Plants use sugar produced during photosynthesis (made from CO₂ and water) as the building material to construct solid structures: cell walls, trunks, stems, and leaves.
Why does a tree's trunk consist mainly of air and water?
Through photosynthesis, a tree converts carbon dioxide (gas from air) and water into sugar, then into cellulose and other solid compounds. The mass came from molecules in air and water.
How does a plant gain mass?
By taking in carbon dioxide and water and converting them into solid organic molecules (sugars, cellulose). The mass of those input molecules becomes the mass of the plant's growing body.
What substance do plants primarily use to build their bodies?
Plants primarily use cellulose, a carbohydrate built from glucose (sugar). Glucose is produced during photosynthesis from carbon dioxide and water.
How is building a plant body related to conservation of mass?
The total mass of CO₂ absorbed and water used equals the mass of the plant matter produced plus the mass of oxygen released. Matter is not created or destroyed — only rearranged.
What grade and chapter covers plants building their bodies?
Grade 5, Chapter 2 of Amplify Science (California): Why aren't the cecropia trees growing and thriving?