Grades 3 through 5
Photosynthesis
Producers make their own food out of light, air and water instead of eating it.
Most students assume a plant eats through its roots. Algae kills that idea quickly. There is nothing in the bag but water, air and light, and by Day 7 there is visibly more algae than there was on Day 1. That extra material came from somewhere, and working out where is the whole lesson.
How the lab meets it
What students do that satisfies the standard
NGSS 5-LS1-1
Standard: Support an argument that the material a plant needs for growth comes chiefly from air and water.
What the kit does: A sealed bag with nothing added is about as clean an argument as a classroom can build. The seeds put on root, stem and leaf, and the only things available to build them with are water and the air trapped in the bag. The algae makes the same case without roots, which removes the usual escape hatch that the plant must be eating soil. Students measure the algae getting denser across the week and have numbers to argue from.
Texas 3.9.B
Standard: Identify and describe the flow of energy in a food chain, beginning with the sun.
What the kit does: Texas has no standalone elementary code for the chemistry itself, so photosynthesis is reached through the producer end of the food chain standard. That is exactly what Bag 2 is. Light goes in, algae grows, and everything above it in Bag 3 depends on that step happening first. Honest fit: partial for Texas rather than a direct match.
Florida SC.3.L.17.2
Standard: Plants use energy from the sun, air and water to make their own food.
What the kit does: Florida names all three inputs, and the bag supplies exactly those three and nothing else. Seeds and algae both run on them. The algae is the more convincing of the two for a third grader, because it has no leaves, no stem and no soil, and it still turns the water greener every day. Florida teaches this two years ahead of NGSS.
Free downloads
Our Lesson Plans
Each lesson is one Word file. Teacher pages and answer keys first, then the student pages behind the orange PRINT FROM HERE divider.
What Eats Light? Grades 3 to 5
What it covers: Where the extra algae came from when nothing was ever added to the bag, tracked with the Secchi Stick across seven days.
How it is built: One Word file. Teacher notes and answer keys up front, then the student pages behind the orange PRINT FROM HERE divider.
The Parts of Plants and Algae. Grades 3 to 5
What it covers: The parts a plant uses to do this job, and how algae runs the same chemistry with none of them.
How it is built: One Word file. Teacher notes and answer keys up front, then the student pages behind the orange PRINT FROM HERE divider.
Administrator Guide
One guide for the whole elementary program rather than one per lesson. This is the copy to hand a principal or a curriculum director.