Students learn sorting algortithms by playing in a group
| Creator | Mikko Muilu |
| Subject | Math, ICT |
| Length | 45 minutes |
| Pedagogical Approach | Phenomenon-based learning |
| Competences | Students learn to compare numbers by sorting |
| Grades | Students aged 9-12. |
| Technologies | Pen and paper |
How to play
Ask all students to stand in a circle. With one student standing in the middle of the circle comparing the ages of the others, divide people into groups in several pairs. This is called the “Merge Sort Algorithm”.
Step 1:
First, make sure the student in the middle knows the months and their order so that he or she can compare the ages of the other students in the correct order.
Give the student a pencil or marker and a post-it sticker or tape so they can make a number sheet for everyone, including themselves.
Have the person chosen write each student’s birthday clearly in the middle of the sticker. The date should be large enough for him or her and other students to read.
Place each number sticker in the center of the chest so that it helps each student can easily see it.
Step 2: Testing the Merge Sort algorithm
Ask your student for a number sticker and place it in the middle of the chest. Ask everyone to stand in a circle. Then have your student compare the numbers. Listen carefully and ask leading questions.
After this first experiment, have your student explain how he or she makes the decision to put all the students in order of age. He should make his decision based on numbers, not assumptions. Will he compare all at once or will he first compare two or more pupils in pairs and then decide?
Let’s start with the introduction, “Merge Sort Algorithm”. Explain to your student what the “Merge Sort Algorithm” is. Take plenty of time to explain how it works clearly.
The Merge Sort Algorithm is based on the principle of dividing things into smaller parts, in our example people, with two people in each part. For example, say there are 16 guests in a class, break them into two groups, and then continue breaking those groups into halves and halves again until the 16 people are divided into parts of one person. Then reunite the people into pairs, but this time sort them in ascending order. When combining pairs, put people into groups of four and in order of age.
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Step 3: Start the sorting
Have your students compare the numbers (ages) of the students.
Observe whether he or she swaps students between groups if they are in the wrong order. Pay attention to how he solves the order problem.
Discussion:
Ask the student to explain who is the oldest or youngest person.
Let him/her explicitly explain how he/she solved this problem. Does he compare everyone at the same time, cluster or scale.
Excercise 2:
Change the organizing student and arrange the students by shoe number using the same principle. Other ways of ordering could be by height, number of siblings, or just by values that are guessed
Discussion:
The important thing to understand is that by inventing a method (algorithm) and repeating it, you can order any number of elements.
