Take 5 cards, shuffle them and lay them out face up. Devise a systematic way to sort the cards. Hint: start with the left hand card and find what goes there. Count the number of comparisons that you make between cards.
You may have discovered the bubble sort or the insertion sort or the selection sort. Try this:
look at the first card and compare it with every other card in the row; if the new card is less than the first card then swap them over; by the end of the first row the lowest card should be in the first location; now move to the second card and repeat the actions.
How many comparisons did you make?
Now try sorting the cards by eye as quickly as you can. How many comparisons did you make?
Sort using network on ground. Split into groups of about 8. Write a single letter on a sheet of paper. Stand in a line with the letters in random order. Walk forward 2-3 paces and converge into pairs. Compare letters and have the lowest on the left. Walk forward 2-3 paces and move apart. Repeat the previous procedure until the letters are sorted. If there is an odd number of letters the right hand person should do a comparison with the adjacent person after the other comparisons have taken place.
Bubble sort. Put 8 cards in random order. Devise a strategy to sort the cards into ascending order by systematically comparing pairs of cards. Note how many comparisons are made to sort the cards.
Mergesort.