S3.2.2 For the adult
Using and making keys
I found a small creature under a stone. How can I find out its name?
What this chapter teaches
A branching key names a living thing by yes or no questions about clear clues. Making a key means choosing clues that do not change, and splitting the group in two at each question.
Three questions to ask
There is no one right wording. Listen for the idea.
- Can you use the key to name an animal in the picture?
- Why is "Is it big?" a poor question for a key?
- How many questions does a key for five animals need?
After the chapter, the learner can
- Use a branching key to name an unknown leaf or insect
- Make a key with yes or no questions for four animals
What they copy into their notebook
A key is a set of yes or no questions. Each answer leads along a branch to a name. Choose clear clues such as legs, wings or a shell. A key for n animals has n − 1 questions.