Main Idea-The van Helmont Willow Experiment

A main idea worksheet that does double duty as science. This one-page graphic organizer pairs an original nonfiction passage with a clean three-part frame: topic, main idea, and two supporting details.

The passage tells the true story of Jan Baptist van Helmont, who planted a five-pound willow shoot in 200 pounds of soil and waited five years to see what would happen. The tree gained more than 164 pounds. The soil lost about two ounces. Students weigh those two numbers against each other and arrive at the main idea themselves — that almost all of a plant's weight comes from carbon dioxide gas in the air, not from the soil it grows in. That conclusion directly confronts the most common misconception in middle school life science: that plants eat soil.

The title gives nothing away on purpose. Students have to build the main idea from the evidence instead of copying it off the page.

Write-in boxes are sized for real handwriting, the passage and organizer stay together on one page so students can reread as they work, and a complete answer key with sample responses is included. Prints cleanly in black and white.