1. Active Learning of Computational Thinking
Gerald Futschek
Vienna University of Technology
Institute of Software Technology & Interactive Systems
DidactIG 2013
Liberec

2. Computational Thinking
"Computational Thinking is the thought processes involved in formulating problems and their solutions so that the solutions are represented in a form that can be effectively carried out by an information-processing agent."
Cuny, Snyder, Wing
Jeanette M. Wing
Computational thinking means thinking algorithmically and with the ability to apply mathematical concepts such as induction to develop more efficient, fair, and secure solutions. Center for Computational Thinking, Carnegie Mellon

3. Challenge no. 1
“What are effective ways of learning (teaching) computational thinking by (to) children?”
Jeanette Wing, 2008, Computational thinking and thinking about computing, Phil. Trans. R. Soc. A. vol. 366(1881),

4. Active Learning Student centered learning
Teacher poses problems to be solved
Teacher does not present solutions
Students are active in finding, describing, constructing, improving and verifying solutions of given problems
Students cooperate

5. Tangible Objects in Education

6. Tim the Train (common work with Julia Moschitz)
consists of a set of wooden elements for train, containers and load parts
and a set of symbolic commands
it describes a bin packing scenario.

7. Tim the Train: Playing a given algorithm
…the train at the beginning of the algorithm
1st part
2nd Part
3rd part
4th part
5th part
6th part
… a sequence of incoming parts
… a sequence of commands (algorithm)
Learning Scenarios with Tim the train. One of the first steps is playing a given algorithm. The learning scope of is to familiarize with the learning scenario Tim the train and the meaning of the symbols. At first you see the train at the beginning of the algorithm. Addionally, a sequence of incoming parts and an algorithm is given.
… the train at the end of the algorithm

8. Playing a given algorithm with Tim the Train
Educational objectives
learning the meaning of symbols
learning executing the commands
Lessons learned
meaning of symbols was easily understood,
Learning executing was harder, e.g. which one is next command
In this example you see a Tim the train and two girls (6 and 9), who are playing the given algorithm. It is their first time, that they have contact with algorithms. In this video you have the possibility to see which problems the girls have. One of the problem is, knowing the position, where they are in the algorithm.

9. Playing a given algorithm
Sequence of commands given by younger sister

10. Tim the Train: Binpacking
Problem: Given is a sequence of parts. Find a sequence of commands that fill the wagons of the train with as many parts as possible. The wagons must not be overloaded.

11. Variants of Playing Algorithms
The teacher plays an algorithm
Some of the students play an algorithm, the others are observing
All students play an algorithm
Which variant has the highest impact on learning success?
An algorithm given by the teacher
An algorithm invented by the students
Which variant is more motivating?

12. Inventing and Playing Algorithms
Task: Find the maximum value A first Algorithm invented by students:
say max :prevvalue :myvalue …
say :myvalue
say max :prevvalue :myvalue
say max :prevvalue :myvalue
output max :prevvalue :myvalue
Teacher: „Well done, but this algorithm takes a long time to find the maximum. All of you are most of the time not busy. There must exist a much faster way to find the maximum value.“

13. 2. Algorithm, students are sitting in rows… 23 6 5 7 2 25 12 20 19 15 4 8 24 22 16 28 21 17
say max :prevvalue :myvalue
say max :prevvalue :backvalue :myvalue
output max :prevvalue :backvalue :myvalue

14. Arising Problems Playing in last column is not easy:
the players get two values
they don‘t know which one comes first
maybe both values come at the same time
Information may be lost
Better to synchronize the players, when information is passed

15. Synchronized message passing
Pass the value, only when both players look into each other eyes

16. Algorithm for Maximum, solution 3
Divide & Conquer strategy:
Each student can sit or stand and has a memory for a single number
Standing students are still in game, sitting students are already out of the game
all students are standing and record their initial number
while there are at least 2 students standing do if you are standing
find a student who stands too, synchronize and
record the maximum of his number and your number,
one of the two is sitting down 5 1 2 3 4
very fast in large groups, O(log n)

17. Algorithm for Maximum, solution 4
Each student has his number on a tablet that can be seen by all other students
At the beginning all students are standing.
Each student performs:
Then the value of the remainig standing students is the highest value
repeat
find a standing student,
if his value is higher than your value, then sit down
until all standing students have the same value
Highly parallel algorithm.
No synchronization necessary.
Needs reading access for all students to all values.
O(log n).

18. Algorithm for Maximum, solution 5
At the beginning all students are standing
One player is the leader of the game (maybe it is the teacher)
very efficient, O(log n) in average
can be played for eample with the last three digits of the student number
repeat
the leader asks one of the standing students to tell his number
the students with lower values sit down
until all standing students have the same value (the maximum value)

19. Solution 6 (Binary Search)
It is known that the maximum value is between a and b, exactly in the interval [a,b)
Idea: Half the interval at each step
Can also be played in a stadion with thousands of people (loudspeaker) to find for example the eldest visitor
O(log n)
repeat
the game leader asks who has a value of at least (a+b)/2
if at least one exists
then he let sit down the other ones and sets a to (a+b)/2
otherwise he sets b to (a+b)/2
until b-a = 1

20. A Cyclic Learning Process
The process of learning by inventing algorithms

21. Auditorium (Class) Games
Possible problem statements:
determine the exact number of students
determine the eldest/tallest student
distribute copies of information sheets to all students
determine the most frequent given name of the students present
Build a maximum number of groups of 3 students
etc.

22. Dancing Algorithms In Youtube: Dancing Sorting Algorithms
Insertion Sort
Selection Sort
Merge Sort
Quick Sort
Nice to look at
But is it active learning?

23. Active Learning by Dancing Algorithms 1
Tasks:
1. Write a choreography for dancing an (sorting) algorithm
Clear stepwise instructions for all dancers
The instructions should work for all permutations of the input data and for any data size n

24. Active Learning by Dancing Algorithms 2
Tasks:
2. Improve the choreography
so that it is easier to understand how the algorithm works
3. Give a choreography for a concurrent (parallel) execution of the algorithm
Which actions can be performed in parallel
How to synchronize the parallel activities?

25. Active Learning by Dancing Algorithms 3
Tasks:
4. Give a dance performance for each of the tasks 1-3 (test of algorithms)
The dancer should strictly follow the given instructions
If a dancer cannot perform a given instruction the algorithm aborts  the choreography has to be improved

26. Thank you very much for your attention!
Gerald Futschek
Constructionism 2014
Vienna, Aug. 2014

27. The Approach 1. give problems that are simple to understand
everybody can easily think about the problems
has a variety of solutions
there is space for creativity and own solutions
2. let the students invent algorithms
3. and let the students play their algorithms
(learning by exploring)