Binary Search

The value of an activity is not just in the doing of the activity, but also the talk that occurs around the activity. This isn't a new concept, we all know it.

Let's take Maths for example- there is value in students playing games to reinforce their knowledge and skills. There is a wealth of games out there, and I am not knocking them. They have a valid place in our classrooms, as long as:

* The teacher is testing them out first

* They target the learning objective

* They are planned for

* Screen time is limited throughout the day

However, real value can be added through the talk around the game. 

Example: Guess The Number by www.abcya.com 

I really like using ABCYA's Guess the Number game as a whole class warm up. We put it up on the big screen and start with numbers to ten. 

Discussion begins with playing the 'numbers to 10' version. I introduce the games, we play a couple of rounds. Players need to guess the number within a certain number of guesses. If you are successful in guessing the number, a cute animal picture pops up that the class just LOVE. We usually quickly move on to numbers to 100. It is also a good way to introduce the vocabulary of greater than and less than. 

We could halt the discussion there, and it would be an o.k. piece of teaching. Students could go off and independently play the game successfully and consolidate their number knowledge. Value added: limited.

To add more value, we then talk about strategy for the game. Usually at least one student will notice that it is possible to eliminate large sets of data by selecting the middle number first. The game then tells us if we need to go higher/ lower. By explicitly discussing this strategy we have added value. We can now talk about halves and find halves of numbers and students are now thinking in a really strategic way. 

One student said the other day (paraphrased by me): "We know the number is between 50 and 100. So there are 50 numbers left. If I halve 50, that is 25 and 50+25= 75 so let's try 75 next".  

Try it, its a great conversation to have.

But let's take the talk one step further and link to the Digital Technologies curriculum. Computers have a range of methods for searching through data. One is called a binary search. 

A binary search is useful when a range of data is organised in order (e.g. a hundreds board). Using the binary search method, the computer takes the data and divides it in half. It then asks "is the item on this side or that side" (or is it "higher" or "lower"?). The computer can then eliminate half the data in one step. 

By continuing to halve the remaining sets of data, a computer can drastically reduce the number of steps it needs to take to find a specific piece of data. 

Let's compare it to a linear search. If we did a linear search, we would go through each piece of data and ask "is it this?" 

To use our Guess My Number example, we would go through and ask is your number one? Is your number two? Is your number three? until we find the correct number.

This is a really big concept that students don't NEED to encounter until a later age, however it is a way of approaching a conversation in an achievable and understandable way.

Value Added.