LESSON 1 - WHAT IS MILKWEED?
OBJECTIVES:
VOCABULARY:
MATERIALS:
BACKGROUND:

Native milkweeds (Asclepias spp.) are best known for its larval food for the monarch butterfly. It also has a unique flower structure and production of pollin. The pollen is not the powdery individual grains, but as special packets called “pollinia.” This pollinia is rich in nectar for the insects, so highly sort after. The only other major group of plants that have these packets are orchids.

Milkweed has distinctive seed pods that produce wind-borne seeds. The fleshy pods split when mature, releasing the seeds. Milkweed produces a milky substance that is contains latex and complex chemicals that make the plants unpalatable to most animals. When the plant is injured, stems, leaves, and pods ooze this white sap.

There is over 70 milkweed species native to United States and Canada. The diverse Asclepias genus ranges in habitats from desert to tropical. Flowers vary in color and fragrance. Many milkweeds are perennial while a few are evergreen. Milkweeds typically flower in late spring and the end of summer. Seed dispersal follows the growth cycle. The perennial species remain dormant through the winter and reemerge in spring from its root system.

The first year the young milkweed builds its roots. Deep sturdy roots that will help it survive drought, floods, and freezing temperatures.

The second year plant is now able to produce a considerable amount of foliage. Adult Monarchs will readily find the plant. Scientists still aren’t certain how monarchs recognize milkweed from the air, but once they land on it, chemical sensors on the feet of the Monarch recognize the milkweed.

Flowers at last! The third year a mature milkweed plant has developed, it produces large lush foliage, ample flowers, and will serve as a nectar source for adult butterflies and bees, and there is plenty of leaves for the caterpillars. After a long-bloom that can last much of the summer, seed pods will form that open in the fall, starting the cycle anew.

PROCEDURE:
  1. Ask students this riddle:

    I follow you around in the light, I say good bye to you in the night? Who am I? Shadow!

  2. Tell students their long term project will deal with shadows from the sun so it is important to understand how shadows work. Are there shadows in the classroom? Why or why not?. If you have the projector on talk about shadow puppets. Might show them an object and have them predict what the shadow would be like. Go outside (optional) and have the students find their shadow. Ask them to see if they can make their shadow longer or shorter.
  3. Illustrate how shadows change during the day if you are outside.
  4. Use the shadow stick in front of some white surface or butcher paper. Use a heat lamp or flashlight to project different angles. Have students predict where they think the shadow will project. Have students predict what they think the shadow will look like. Engage the class into determine how to make it larger or smaller. The heat lamp would represent the Sun.
  5. Use a white piece of paper and put a marker (with flat head) standing in the center. Have the students experiment with different angles as they try and make the shadows move around. Ask students how can they make the longest shadow? Shortest? Fattest? Thinnest? Have them demonstrate to you or the class how to position the light to get no or little shadow vs. really long shadows
  6. May want to have students design a shadow object with their hands and give a few students time to show their creation and rest of class figure out what it is.