Tracing matter in the gaseous form is difficult to teach and requires carefully planned activities. Plant growth is one way to teach students that most of the mass of the plant comes from somewhere other than the soil, but mostly in carbon dioxide and hydrogen atoms from water. To identify this, students will be planting seeds indoors, weighing the dry pot, soil and seed first and then the dry pot, soil and plant later. The total mass of the soil and pot will be nearly equal before and after the experiment. Students will also measure plant height throughout the experiment. Students will be able use the data from the experiment to make graphs and conclusions, which are important concepts for upper elementary students. After discovering that most of the plant mass does not come from the soil, it will be explained that carbon dioxide is the primary “food” for plants. Students will be assessed based on data collection, graphing and conclusion paragraphs.
At the conclusion of this lesson, students will be able to:
- Recognize that gases have mass and can be used to make living plant tissue
- Conduct an experiment to answer a scientific question using data collected
- Successfully grow different plants in a classroom setting and take accurate measurements
Resources for this lesson include: