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Plant Adventures    Mystery 3

Mystery 3 image

In this Mystery, students will learn the importance to sunlight to plants, which is collected by their leaves. Knowing how plants respond to sunlight, they will build creative Grass Heads. This mystery requires two class periods.

Why do trees grow so tall?

Beginning Exploration (1 of 11)
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Beginning Exploration (2 of 11)

Predict:

After 2 weeks, what do you think will have happened to the plant in the dark compared to the plant in the light?

Turn to someone next to you. Tell them your prediction and your reason why.

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Beginning Exploration (3 of 11)
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Beginning Exploration (4 of 11)

Discuss: Why might the plant in the dark have grown taller? Look closely at the plants to see if there are any clues.

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Beginning Exploration (5 of 11)
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Beginning Exploration (6 of 11)

Discuss:

Why do you think the leaves are moving?

plantsmoving

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Beginning Exploration (7 of 11)
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Beginning Exploration (8 of 11)

Discuss:

How can a tree get more sunlight when a lot of other trees are starting to get in its way?

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Beginning Exploration (9 of 11)
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Beginning Exploration (10 of 11)

Discuss:

So now if someone asked you, "Why do trees grow so tall?", how would you explain it to them?

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Beginning Exploration (11 of 11)
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Beginning Activity: Grass Head
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Activity Prep

Step 1: Get supplies and print worksheets.

Each student will need:

  • a Grass Head worksheet — print it here
  • a ruler
  • a ballpoint pen or Sharpie (water-soluble markers will not work)
  • a popsicle stick
  • 3 small rubber bands
  • 2 paper towels
  • a paper plate
  • a nylon kneesock, cut as described below (Available in boxes of 10 pairs at drugstores and on Amazon. Ten pairs is enough for 40 students.)

In addition, you will need:

  • about 2 cups (about one pound) of fast-sprouting grass seeds — check your hardware store for something like this from Home Depot or this from Amazon.
  • bowls to hold ¼ cup of grass seed (one bowl for each group of 4 students)
  • cups of water (one cup for each group of 4 students)
  • a few ceramic coffee mugs and four plates (styrofoam, plastic, or ceramic) for the grass heads while they are sprouting. (Plates must have raised edges so they’ll hold water.)

Step 2: Before class, complete final preparations.

This step takes about 15 minutes.

Cut the stockings in half and tie the open ends as shown in this video.

Label two plates “Face Up” and two plates “Face Down.”

Step 3: After class — maintenance

The paper towel of the grass head will soak up water and keep the seeds wet — but only if part of paper towel stays wet. Make sure to keep a water supply in each plate and cup so your grass heads stay wet. Grass heads can soak up lots of water.

Your class will examine your grass heads during the next mystery. You’ll talk about whether students’ predictions were right and will find a surprise. For more on that, see Mystery 4: Should you water a cactus?

Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Activity: Grass Head (old)
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Beginning Complete!

You've completed the Exploration & Activity!

If you have more time, view the reading and extension activity in the optional extras.

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Optional Extras

Below are ideas for extending this topic beyond the activity & exploration which you just completed.
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Extra Activity:

How to Train a Bean Plant

In this Mystery, we showed photos of a bean plant that we grew here at Mystery Science. We planted the bean in a cardboard box with a hole in it. The bean grew toward the light, snaking its way toward the hole to escape the dark box.

You can duplicate this experiment in your classroom. Just follow these detailed instructions on the website of the Chicago Botanic Garden.

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Time Lapse Video:

A Year in the Forest

In less than three minutes, this amazing video shows your students how a forest changes over the course of a year. This can be used as an interactive classroom exercise in observation. Ask students to raise their hands when they know what season it is in the forest. Stop the video when enough hands are up, then ask students to explain what clues tell them the season.

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