After you have started a number of seedlings you can start assigning them to different conditions. Three tests:
How does light help a plant? How can you tell if a plant doesn’t get enough light? Label one group "A" and the other group "B" . Put "A" in a sunny place and put "B" in a darker place. Always water ‘A’ and ‘B’ the same amount. Have the students write predictions about what will happen. Later, have the students describe and record in writing what happened to "B".
How can you tell a plant is dry? Another test proving what happens in a drought. Label one group "X" and the other group "Y". Water "X" everyday and never water "Y". Keep both groups in the exact same place. Compare both germination and seedling survival in this way. Model for them how to record each step in their journals. Write predictions and see the results. Review the entries from before and ask students if there was anything that survived without water among our seedlings?
Sun seekers - Keep a seedling near a window. Mark one side of the pot "M" and the other side "O". Face the side marked "M" to the window. Show students that many plants will lean toward a window over the course of a few days if they are not receiving enough light. Have the students record that the side marked "M" is facing the window. If you turn the plant so that "O" faces the window, and no one moves the plant, the leaves will turn back around to face the window again two days later. Try this with both the seedlings and mature vine plants. It’s called phototropism. Sunflowers do the same every day. In Spanish, the name of the flower is a ‘bend to the sun’ .
Everything is recorded in the journals. Be sure students start a new page when starting a new test on the seedlings, one at a time, one on a page. Students should include drawings of the cups, captions, with their writing to keep track of the different tests. In a few weeks we take a short time to read back what we wrote. Then we talk about how everything changed since we wrote that entry that day.
The preparation is to sow seeds in cups in early spring. Keep them moist and when you have about 12 or more these experiments are great examples of common science objectives.
What does a seedling need to survive?
Water and Light