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20 Questions
In this activity, students will learn a variety of leaf and twig characteristics. They will use this knowledge to identify and name local trees using a simple on-line pictoral key. |
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20 Questions
In this activity, students will learn a variety of leaf and twig characteristics. They will use this knowledge to identify and name local trees using a simple on-line pictoral key. |
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Most kids have played "20 Questions", but what they don't realize is that they are really practicing a technique scientists use when they identify plants and other living creatures with a dichotomous key.
Introduction:
Play "20 Questions". Pick something or someone in the classroom the students can see. After finding the correct answer, go back and process the strategy students used to narrow their answer down from everything in the room to the one correct answer.
Scientists use this same strategy when they come upon a plant or animal they have never seen before. They might first ask "Is it a plant or an animal?" If it is a plant, the next question might be "Is it a tree (over 20 feet when full grown) or not?" Each time a question is asked and answered, the scientist eliminates some of the possible answers, gradually coming closer and closer to the correct name for what they have found. In this activity, students will see how they can apply the "20 Questions" concept to a real scientific question.
Learning Leaf and Tree Parts:
Before students can solve the "what is this" question, they need to know a bit of the language scientists use when they identify plants. The on-line key does a very good job of showing students some pictures that help define "opposite" and "alternate" branching, leaf shape, etc. If you wish to prep them a litle more, you could do this tree terms matching activity (a pdf matching page) to learn those terms.
Preparation for the Computer Lab Activity -
1. Ask students to bring in a few leaves that have fallen from trees. If possible, try to include a few Sugar Maple leaves.
2. Students should also look up into the tree the leaf fell from to see if the branching for that tree is alternate or opposite. Kids can use the diagrams on the tree terms page.
opposite
alternate
In the Computer Lab:
Ask students to go online and open their browsers to the EEK Tree Key Start page at
They can also get there from the Wolf Ridge Spring Happenings Sugar Maples page by clicking the "Tree Key" link in the Websites area.
To use the key, students click on the link with the drawing and description which best represents their leaf and twig or sketch. When they have made their final choice and identified their tree, they can click on a link to a more detatiled description of that species. Ask students to read the description and pick one fact to share at the end of class.
Conclusion:
Scientists use identification keys not just to show off how many plants they can name, but as a "key to knowledge." Once you know the name of something, you can find out what others already know about it. Ask students to share the facts they learned. From here, they could do an internet search for Acer saccharum or Sugar Maples.
