Lesson video

Hello, my name's Mrs. Jones.

I'm really pleased you decided to join this lesson today.

In this lesson, we will look at data and how this is represented in different ways we see today and how it is represented on computing devices.

So let's get started.

Welcome to today's lesson.

Today's lesson is called "Representing information" from the unit Data representation: text and numbers.

And by the end of this lesson, you'll be able to explain how representations are used to store, communicate, and process information.

There are two keywords to today's lesson.

Symbol.

Symbol is simply something that stands for something else.

Representation.

Representation is the form in which data is stored, processed, and transmitted by a computer system.

There are two sections to today's lesson.

The first is explain how data is represented on computers.

The second is choose an appropriate representation.

So let's start with explain how data is represented on computers.

Why is the invention of writing so important? Aisha says, "Because people write things down to communicate, like writing a letter." This is an example here of a clay tablet, which is from 3100 to 3000 BC on display at the British Museum.

Lucas says, "People write things down to remember or store information." Messages can be transmitted across long distances.

Messages can be stored for long periods of time.

You can communicate with many more people.

You can share knowledge.

Sequences of symbols can represent any piece of information.

Here you can see an example on the left of how different symbols, different drawing symbols can represent different meanings.

You can see across the top we have fish, bird, axe, arrow, and bottle, and how down the left you've got the different areas.

Here we've got China and Egypt as well.

So you can see that different symbols can have different meanings, and that represents on the tablet on the right there on that stone where the symbols can be seen, and each drawing has a different meaning.

Sam says, "How did people know what these drawings meant?" Really good question.

Communication only works when everyone understands the message.

In this case, the symbols must have meanings that everyone agrees on and knows how to use.

Sam asks, "What is a symbol?" A symbol is simply something that stands for something else based on an agreed rule or understanding.

It might be a shape, a heart for love, a letter or character.

The plus symbol stands for add.

Any image or sign that points to a different idea or object.

Let's have a quick check.

How do we know what a symbol represents? A, we make up our own meaning each time.

B, we use agreed rules or codes everyone understands.

C, it changes depending on the person reading it.

Pause the video to consider your answer and then we'll check it.

Let's check your answer.

The answer was B.

We use agreed rules or codes everyone understands.

Well done if you got that correct.

Data versus information.

Data is facts and figures in their raw form.

Raw form means that the facts and figures haven't been changed or organised in any way.

Information is processed, organised, and structured data that provides context and meaning.

Information is represented in computers as data.

Let's have a quick check.

True or false? Data is processed, organised, and structured data that provides context and meaning.

Pause the video to consider if that is true or false, and then we'll check your answer.

Let's check your answer.

The answer was false because information is processed, organised, and structured data that provides context and meaning.

Data is facts and figures in their raw form.

Well done if you got that correct.

Computing systems are used to store, communicate, and process all different types of information, and this includes numbers, text, characters, images, audio.

Information in computers must be represented in a form convenient for processing.

At the lowest level, computers only process data as binary sequences of bits, zero or one.

Ultimately, computers use sequences of symbols, zeros and ones, to represent all types of information.

Every piece of data a computer processes or stores has to be converted to and from binary.

Let's do an activity, and you'll need your worksheets.

In your own words, explain how computers represent data.

Pause the video, go back through the slides, use your worksheet, and then we'll check your answers.

Let's check your answer.

Computers don't understand words or pictures like we do, so everything has to be turned into binary data, zeros and ones.

Every piece of data a computer processes or stores has to be converted to and from binary.

Well done if you got that correct.

Let's move to the next part of today's lesson, choose an appropriate representation.

The way we show information matters.

The right choice can make things easier to understand, faster to process, more useful for the task.

Do you recognise any of these methods of representing information? Have a look at those pictures for a second, and then we're going to go through them.

Each one of these is a different way of representing information.

The top left is semaphore flags.

Top right, we have barcodes.

In the centre, we have braille.

Bottom right, we have QR codes.

And bottom left, we have British Sign Language.

And we're going to look at semaphore flags, braille, and British Sign Language in a little bit more detail.

Semaphore flags are a way of sending messages using two handheld flags.

The position of the flags represents different letters and numbers.

Ships in the navy use semaphore flags to send messages between boats.

They're also used on railways to send signals to train drivers.

British Sign Language, BSL, is a visual language used mainly by deaf people in the UK to communicate using hand signals, hand signs, facial expressions, and body movements.

Each word or letter has a specific sign.

BSL has its own grammar and structure.

It's not just English with hand movements.

Braille is a touch-based writing system used by blind people and people with low vision.

It allows them to read and write using raised dots that can be felt with their fingers.

Each letter, number, or symbol is made up of one to six raised dots arranged in a small grid.

Let's have a quick check.

Which representation involves using coloured flags for communication? A, braille; B, British Sign Language; C, semaphore.

Pause the video to consider your answer, and then we'll check it.

Let's check your answer.

The answer was C, semaphore.

Well done if you got that correct.

Sequences of different symbols can represent the same thing.

Here we've got a sequence of sign language, British Sign Language, we have braille, and we have the semaphore flags, and each one of those is representing the same thing.

Lucas says, "These all represent the word symbol." The same sequence of symbols can represent different things.

The word dab means a number of different things.

It can be a type of fish, a sudden blow or thrust, a gentle touch or stroke, a small amount, a skillful person, a dance move, the musical notes D, A, B, the number 3499, digital audio broadcasting.

Let's have a quick check.

Why can the same sequence of symbols represent different things? A, because symbols are always random.

B, because symbols never change.

C, because people and systems agree on different meanings.

D, because all symbols mean the same everywhere.

Pause the video to consider your answer and then we'll check it.

Let's check your answer.

The answer was C, because people and systems agree on different meanings.

Well done if you got that correct.

Let's do an activity.

Read each of the scenarios carefully and identify an appropriate representation to use.

A, two battleships are trying to communicate, but all electronic communication equipment is not working.

B, a library wants to track which books are borrowed and who borrowed them.

C, a sports event wants to give ticket holders quick access to the event.

D, a doctor's surgery wants to provide a leaflet of information for patients who are blind or have low vision.

Pause the video, use your worksheet, and consider each one of those scenarios and which type of a representation would be appropriate to use, and then we'll go through the answers.

Let's check your answers.

A was two battleships are trying to communicate, but all electronic communication equipment is not working.

In this case, the sailors on each boat could use semaphore flags to communicate with one another.

In the second scenario, a library wants to track which books are borrowed and who borrowed them.

And in this one, the library could generate unique barcodes for each book.

The barcode could be scanned and details about loans held on a computer system.

The third scenario was a sports event wants to give ticket holders quick access to the event, and in this one, the sports event could generate QR codes for ticket holders.

The QR codes could be scanned at the entrance to allow ticket holders quick access to the event.

And the next scenario, a doctor's surgery wants to provide a leaflet of information for patients who are blind or have low vision.

In this one, the doctor's surgery could print the leaflet in braille, so patients who are blind or have low vision can still understand the information.

Well done if you got those correct.

In summary, there are many types of representations, such as text, numbers, images, sound, and symbols.

Representations help us store, share, and work with information.

Sequences of zeros and ones are used on computers to represent all types of information.

Different representations may be suitable for different situations.

Well done for completing this lesson on representing information.