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Background Information, Activity Setup:
• Students will categorize office supplies and identify characteristics that are unique to each item. Make 4 baggies
with 4 items each
Baggie 1—pencil, pen, color pencil, highlighter
Baggie 2—staple paper clip, paper fastener/ brad, thumb tack
Baggie 3—note card, sticky note, sticker, tissue
Baggie 4—eraser, tape, stamp, rubber band
• Sort students into 4 groups.
• Each group will get 1 bag and "These Things are not Like the Other" Handout
• Give student 5 minutes to investigate each baggie.
• Students will rotate bags to next group until all bags are investigated.
DO NOT GIVE STUDENTS ANY ANSWERS DURING INVESTIGATIONS! THIS IS A DISCOVERY LESSON!
Step-by-Step Procedure:
1. Sort students into 4 groups.
2. Each group will get 1 bag and "These Things are not Like the Other" Handout
3. Give student 5 minutes to investigate each baggie.
4. Write the four items on the handout.
5. For each baggie the students will write down one rule that ALL contents in the bag follow.
– Example: Baggie 1 contains a pencil, pen, color pencil, and highlighter.
– One Rule all contents in this bag follow: They are all writing utensils.
6. Next students must write down a set 3–5 rules that each individual item has that makes it unique from all other items.
– Example: Baggie 1 contains a pencil, pen, color pencil, and highlighter.
– Pencil is unique because it is yellow, it has metal, it has a pink eraser, it has lead.
– Pen is unique because it is blue, it has ink, it is made out of plastic, cannot be erased.
– Color pencil is unique because it is purple, it has purple wax inside, it does not have an eraser
– Highlighter is unique because it is orange, it is see-through not solid, it makes thick marks
7. After 5 minutes, rotate bag to the next group and receive a new bag.
8. Repeat the process until all bags have been investigated by each group.
9. Pass out the "Secret Code Dichotomous Key" handout and "Secret Code Answer" document.
10. Say: "Did you know that all these supplies have secret names? I want to see if you can figure out the secret names of all
these office supplies. The rules you created, and this handout give you clues to help find out what each objects secret name is.
Let's do one together."
11. Teacher will pick an object and guide students to discover the objects secret name.
12. Students can work together to decipher the remaining objects names.
13. At the end of class, reveal what the definition and function of a dichotomous key is.
Expected Results:
Students will learn how to decipher a dichotomous key to identify organisms. Students will know that dichotomous keys are used
by scientists to classify organisms.
Teaching Notes:
Depending on class size, you may want to create two sets of bags and make eight groups instead of four.
Secret Code Game—Discovering Dichotomous Keys
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