1. Is it alive? - Lesson Plan
Glue monsters demo:
- Fill a Petri dish half full with water.
- Place the Petri dish on an overhead projector.
- Fabricate some story about small, blob-like monsters that live in the local watershed. Add a drop of Duco® glue to the water in the dish.
- To “feed” the “monster”, sprinkle a small amount of the pencil shavings or pepper near the “monster”. It should move towards the shavings or pepper and “eat” them.
- Add additional drops of glue and watch “monsters” interacting with one another.
- When the “monsters” slow down, turn off the projector and ask the students for their observations. What did they see? What happened when “food” was added? How did the monsters interact with each other? Most importantly, were they alive and how could you tell?
- After students reported their initial observations, do the demonstration again, this time very obviously showing students that it was a trick – the “monsters” were just drops of glue in water and the “food” was pencil shavings. Briefly explain the chemistry behind the demonstration.
- Discuss what characteristics they used to initially decide that the “monsters” were alive. Students will generally point out how they “moved on their own”. Ask students whether all living things “move on their own” and look for counterexamples like plants.
Alive or not alive card sorting:
- Describe the card sorting activity to the students. Working with a partner, they should divide the items on the cards into 4 categories: alive, never alive, once was alive, and not sure.
- Divide the students into pairs, distribute the sorting cards, and allow students to get started.
- Circulate around the room helping students that have questions. If an item is unfamiliar, describe what the item is without necessarily giving away whether it is alive or not.
- If groups finish early, you may ask them to come up with their own cards and add them to the set.
- When most groups are done, pull the class together to discuss their conclusions. Begin the discussion by creating a master list on the board. Have students name the items within each category that were easy to classify. Then discuss the more difficult items one by one. Don’t tell students the “right” answer. Allow them to make mistakes. In your discussion, repeatedly ask students to explain:
You may wish to keep a list of those items that were miscategorized and those that had disagreements. Revisit this activity at the end of the unit as a way to review.
- what criteria they used to make their decisions
- what all the living things have in common
Characteristics of life list:
- Give each pair of students the task of creating a list of characteristics that they believe all living things have in common. Students should make sure that each criteria applies to all the living things from the card sorting activity. It is important that both students agree on every item. Both students should make their own copy of the list on a separate sheet of paper. Allow students around 15 minutes to discuss the problem and come up with their list.
- When each pair has a list, rearrange students into groups of 4. The original pairs should be split apart into different groups. In these new groups, the goal is to come up with a consensus list, one that each person in the group agrees with. Do not allow voting. Allow students around 10 minutes to come to consensus.
- Have each group read their list to the whole class. As they read out their lists, write down the characteristics on the board putting tally marks next to those reported by multiple groups.
- Moderate a discussion to come up with a consensus list for the whole class. Have different groups explain the reasoning behind criteria that there is disagreement about. When everyone (including you as the teacher) is comfortable with the consensus list, create a class poster with all the characteristics of life listed. This poster will be revisited and revised over the course of the next few weeks as students become more sophisticated and learn new concepts.
Submitted by irene on Sun, 2006-07-23 22:01