An Exercise in Active Learning (Grades 2-4)
ACTIVE LEARNING EXAMPLE 1
Below is a possible scenario that could develop as you and your students try to answer the question posed.
The Monarch flitted from plant to plant, touching down lightly for a second and then, like a leaf blown in the wind, was off again until finally she discovered a patch of milkweed.
Teacher: Try to imagine the problem the female Monarch faces as she flies over the meadow. looking for a place to lay her eggs. She has to find a few milkweed plants in a sea of grasses and weeds. How does she find these few plants? This is a "Where's Waldo" sort of problem.
Student: She sees them.
Teacher: Okay, but if she sees them then why does she land on many wrong plants. Why doesn't she always land on a milkweed?
Student: She makes mistakes. Maybe there are many plants that look like milkweed.
Teacher: If that is true, how might we explain why they look alike to her?
Student: Maybe she can't see very well.
Teacher: That's right. Her vision is not very good. So, if she can't see them then how does she find them?
Student: Maybe she smells them.
Teacher: Where is their sense of smell? Do butterflies have a nose?
Teacher: What do butterflies use to smell with? (You are probing for organs of smell.) If there is no nose, then what else is there? Lead them to the fact that the sense of smell on most insects is on the antennae. Go through a process of elimination to do this. Tongue? Antennae? Eyes? Feet? Then ask- Does the Monarch use antennae to smell? Is that what the story said?
Student: No. It said she touched down.
Teacher: Then if smell works, maybe it's because she is close to the plant. Any other possibilities? What about taste? How would a butterfly taste plants? Are there organs of taste on a butterfly?
Student: They have a tongue or a proboscis.
Teacher: Okay, but do they use this for taste? The story said that the Monarch only lands on the plant with her feet. Any other possibilities?
Teacher: Did the story say that her wings touched the plant?
Teacher: What does touch the plant?
Student: Her feet touch the plant.
Teacher: That's right. That's all we know. Is it possible that Monarchs can taste the plant with their feet? (If there is a live Monarch available, ask students how many legs they have.)
Student: Only 4, I thought insects had six legs.
Teacher: That's right. So there must be another pair of legs and if we look closely we can find them. The first pair of legs is pulled up just below and behind the head. See them? (You have now led them to the conclusion that the Monarchs taste with their feet. and have given them information that was not revealed in the story.
So, you see when the female Monarch lands on a plant she extends these front legs and rapidly taps the plant . At the end of these legs are special spines than have chemical sensors. By pushing the spines into the plant she can taste the plant. If you have access to the internet, there is a picture of these on the Monarch Watch website.
Let's try to summarize what we have learned about how Monarchs find milkweed plants. The first sense we thought they might use was vision. But we decided that couldn't be the only way because Monarch land on many plants that aren't milkweed. Then, someone suggested that maybe Monarchs smell the milkweed plants. Since we know that butterflies don't have a nose, we decided that maybe it is possible that when they get close enough to milkweed plants they might be able to sense the odor in some way. Finally, we remembered that the story said the Monarch touched down on the plant so her feet must be connected to finding the milkweed plants. Then we discovered that she had a special pair of legs and the story said that she extended these legs and rapidly tapped the plant. While we may not be totally accurate, what we discovered as a group is also what scientists think is true and is based on their current knowledge of Monarchs.
HOW TO SECTION
Sometimes even basic knowledge beforehand will not lead the students to the correct conclusion. In this case, try to think of an analogy that they can relate to. Here is an example:
Tell the students that you are going to send them to the store to find apples. When they get there they will first be allowed to look at all the fruit. Then, they will be blindfolded and sent back to the fruit section. Once there, not only will they not be able to see the fruit but they will also not be allowed to touch the various fruits. However, they can smell the fruits. Do they think it would be possible to find apples?
The purpose of using an analogy related to something the students know can then be related back to the Monarch and her search for milkweed. Remember, there could be 100 different plant species in a field but she still manages to find the milkweed without landing on every plant. Monarchs must be using some general information. In fact, they probably use three different senses- vision to locate possibilities, smell to help narrow the search, and taste to know where to lay eggs.