What is the main idea of the story?

Good records and controlled conditions make a tool’s measurements useful. (Jonas loses the meaning of his first data, then uses durable labels, a photo, and equal watering to make the second comparison interpretable.)

Why does Jonas give both trays the same amount of water?

He wants differences in water to be less likely to confuse the lamp comparison. (The lamps are the feature being compared, so treating water equally helps prevent it from becoming a second explanation for growth.)

What is a “sensor” in this story?

A device that measures a condition such as soil moisture (The passage says the sensor measures soil moisture every morning, identifying it as a measuring device.)

Where does Jonas write each lamp’s name during the second test?

On the tray itself (During the new test, Jonas writes the lamp name directly on its tray so the identity remains attached.)

The Unlabeled Seed Trays: Level 2 Reading Comprehension Questions

Jonas tested two lamps for growing herbs indoors. He placed one lamp above each seed tray. Then his cat knocked both labels onto the floor. The trays looked alike, so Jonas could not tell which lamp had helped which plants. His measurements were now useless.

Jonas began again with fresh seeds. This time, he wrote each lamp’s name on the tray itself. He also took a photo before moving anything. Every morning, a small sensor measured the soil moisture. If one tray became dry, he gave both trays the same amount of water.

After three weeks, Jonas compared the plant heights. He could connect each result to the correct lamp because the record had stayed with the tray. The sensor had not decided which lamp was better. It had helped him keep one other condition, water, fair. Jonas learned that useful tools need a careful record around them.

Comprehension questions