Lesson video

Hi there, I'm Sara, your computing teacher.

This is lesson six, and the last lesson on the unit, "Representations from K to Silicon".

In this lesson, you will need to take down some notes.

So get yourself a pen and paper, pause the video, and when you're ready, unpause and continue.

Don't forget also, you need to turn off all notifications, so they're not distracting, and remove any other distractions before you begin.

So see you when you're ready.

In this lesson, you will convert binary digits to decimal digits.

You will convert decimal digits to binary digits also.

And you will find a secret code.

You have learned some really vital skills.

So why not brush up on some of the skills you've learned? You can do that by having a go at binary digits in your task one.

Complete the questions on the worksheet.

Pause the video, and when you have completed, just unpause to continue.

Well done for having a go.

Now, check your answers for questions one to four.

Now on to task two.

Again, complete the questions on the worksheet.

Pause the video, and when you have completed, just unpause to continue.

Well done for having a go.

Now, check your answers against what you've just done.

Now, onto the last task before we begin the lesson, right? Pause the video and complete the task where you've been required to fill in the gaps.

When you have completed, just Play to continue.

Great work.

I bet you're wondering what we mean by Turing's Mug, so I won't keep you so you can find out.

Alan Turing was an English mathematician and a very good one at that.

He's widely considered to be the father of computing and during World War II, his secret work at Bletchley Park was central to decrypting or breaking German communications, which helped win the war.

Now, what do we mean? What's the story behind Turing's Mug? So Turing was an eccentric man.

In his wartime office he would lock his mug to the radiator with a combination lock, so no one could use it.

Now you have been commissioned with this very special mission.

The national museum of computing has uncovered a clue that may help unlock the Mug.

They have asked for your help.

They let you into Turing's office and show you the clue.

Now, before we begin, I will show you an example of the clue that was uncovered.

So this is a series of representation ahead that you can see on screen, and you've worked out that these refer to binary numbers, So I've put there the place value or multiplier, so that would help us as we go through this example.

So take a first look.

Now taking a closer look, you will remember that you do start from the rightmost place value, which is one.

Now, you looked carefully and you've rightly worked out that the white circles are zeros and the black circles are ones, 'cause they've been turned on.

So starting with the first line, the first actual circle there will be zero.

And moving on from there, the next four will be one, zero, zero, and zero.

So adding up just the ones, looking at the place value for the digit we're on, you've only got two.

So that equates to decimal number two.

And as script analyst, you soon worked out that that corresponds to letters in the alphabet and the second letter in the alphabet is B.

Right, going on to the next line, the code there would read as binary one, zero, zero, zero, one, zero.

And adding up the ones, that would give us a nine, and the ninth letter in the alphabet is an I.

So you carry on with deciphering what this means and you get the word Bicycle.

So the letters actually form a word.

Right, okay.

So next, you've flipped through Turing's notebook trying to find clues.

And on the last page, you find a list of words, with the word bicycle, which has just been broken, on it.

Now this is the list of words you find.

Now there's bicycle there, and there are three numbers beside the word bicycle, but what are the three numbers? Right, okay, moving on.

Now you also notice the combination lock and this is an example of a lock.

So how do you begin to break this? Okay, you've soon worked out that this lock corresponds to binary digits.

And in this particular example, you've got the place value four and two set to one.

So when you add four and two, you get six.

So the decimal value of this binary number is six.

Looking at that binary number, you soon worked out that these bars, horizontal bars and vertical bar, switches on, depending on whether you've got a zero or a one.

A zero meant it's switched off, and a one means it's switched on.

So you trace the first digit, it's a zero.

So that's traced all the way along to that horizontal bar.

So that's not switched on because that's set to zero.

Onto the next number, that's set to one.

That combination lock digit is set to one, which means that traced all the way to that vertical bar, means the vertical bar needs to be switched on.

So it's switched on.

Onto the next number, right? Set to one, and that there means that vertical bar there will have to be set to one also.

So that's set to one.

No need continuing, because all other digits are set to zero, so that means that corresponds to a one on your combination lock or on the combination lock given to you.

So that will be a one.

Right, so what are the instructions? Now, you know what to do.

For each number, you set the switches according to the binary number.

So you checked a digit.

If it's set to zero, then that bar remains off.

If it's set to one, like that one, it's on.

The next one, set to one, that's on.

That's set to zero, that's off.

That one's set to zero, that's off.

That one's set to one, that's on.

And that last one's set to one.

So that horizontal bar should be on.

So that's how you work it out.

And in your worksheet, feel free to colour in as you find switched on digits.

So what does this mean for Bicycle? Because we found, or you found, three words next to bicycle, 109, seven, and 111, in this example.

Right, working out what this means, the first digit here, or the first number here, the binary digits, we're going to try and switch on depending which one's on and off.

So in this example, we've got the first ones on, so we'd go right there and we trace all the way to that horizontal bar.

So that should be on, that's on.

The next one's off, so that's going to stay off.

But the next one under the place value force on.

So we're going to trace all the way there.

So that means that bar needs to switch on, which it does, and the next one's also on, so that bar needs to switch on, which happens.

And the next one's off, but the last two are on, so it means that vertical bar there and that horizontal bar there needs to be switched on, which we have here.

So that reveals the number five, so we've got the first digit that we could unlock the combination lock with.

Now, carrying on with that same, in that same manner would uncover the number seven and the number nine.

So which means the pattern to unlock the lock is five, seven and nine.

It's your turn now to have a go at unlocking Turing's Mug.

So you've got a pattern in your worksheet.

Remember what the white stands for and the black.

So the black circles mean to switched on, the white means they're switched off.

Now you suspected these are binary numbers, so you try to convert them to decimal numbers.

So follow what you've just discovered to resolve and unlock Turing's Mug.

So have a go, there's a table that would help you.

And you've got your list of words and instructions.

So have a go at Task Four, at unlocking Turing's Mug.

Pause the video, and when you have completed, unpause to continue.

Here's the solution.

If the word you uncovered, the word you cracked, is Enigma, then well done for deciphering that.

And that means you have unlocked Turing's Mug, well done.

You have reached the end of learning for this unit, Representations.

You have gone right across time, as far back as thousands of years ago, where you saw representations in the form of clay tablets, to modern day times, where you have digital tablets.

You saw how humans resolved the problem of storing, transmitting, and processing information by inventing writing.

You also saw that just like how humans have the need to write, computers have the need to write also.

And computers write using ones and zeros.

And all information held on a computer, be they text, images, sounds, whatever they may be, are all in sequences of ones and zeroes, called binary digits.

So great learning.

On your notebook, I would like you to write one thing that impressed you, one thing that you learned, and one thing that you really did not enjoy, and this is just all to bring this learning together and for you to have a good think about what you've learned in this unit.

I hope you enjoyed it and thank you for joining.

It will be lovely to see your work.

So if you'd like to share, please ask your parent or carer to share on Instagram, Facebook, Twitter, @OakNational with hashtag #LearnWithOak.

Thank you for joining.

And I hope you really enjoyed learning all about Representations, from clay tablets to modern day digital tablets with silicon chips in them.