Rocket and Raven stand under a giant oak in the park. Its trunk is so wide they cannot reach around it together.
"This tree started as one tiny acorn," Raven says. "So where did all this wood come from?"
Rocket stomps on the ground. "Easy. The dirt," he says. "Roots eat the soil."
Nova circles the trunk slowly. "That is what most people guess," she says. "Would you like a hint? Think about what plants take in from the air."
Rocket looks up at the leaves and frowns. "From the air?" he says. "That cannot be heavy enough."
Most of a plant's material does not come from the soil.
Plants get the material they need to grow mainly from air and water.
The water comes up through the roots. A gas called carbon dioxide comes in from the air.
The plant uses sunlight's energy to build these into its own food and body.
Soil is still important. It holds the water that roots take up.
But the wood of the trunk, the leaves and the branches are built mostly from air and water.
| Statement | True or false? |
|---|---|
| Roots eat soil to build the trunk. | ? |
| Plants take in water through their roots. | ? |
| Plants use energy from sunlight to make their food. | ? |
A growing plant takes in three things it needs.
Water comes up through the roots. Carbon dioxide comes in from the air.
Sunlight gives the energy to build them into food and new plant parts.
Great job questioning an easy answer. Tomorrow we will look at a famous experiment with a willow tree.