01What does it mean to turn something into data?

We have already learned that computers can store and process numbers, text, images, sound, and video.

They look very different, but inside a computer they all need to be converted into recordable values and bits according to certain rules.

Information in the real world

Text, sound, images, temperature, location...

Measurement / encoding / sampling

Convert information into values according to agreed rules

010101...

Digital data

Can be stored, transmitted, and calculated

02How do numbers and text become data?

Numbers are naturally suited to numerical representation. Non-negative integers can be written directly in binary; negative numbers and decimals have their own representation rules.

Text first needs a number assigned to each character, and is then stored using an encoding scheme.

Numbers

13 → 00001101

Interpreted according to the integer type and bit width

Text

中 → U+4E2D → E4 B8 AD

A Unicode code point encoded in UTF-8

03How do images, sound, and video become data?

Images, sound, and video are not simply “translated into 0s and 1s.” First, they are broken down into information that can be measured and described.

Images

Common bitmap images record pixel positions and colors

For example, RGB values

Sound

Sampling and quantization record how sound changes over time

For example, PCM sample values

Video

Records changing images over time and often includes audio

Video encoding is then used to compress it

04Can temperature, location, and motion become data too?

Yes. Many physical properties in the real world can be measured by sensors and converted into numbers.

Temperature

26.3 °C

Measured by a temperature sensor

Location

Coordinates

Can be calculated by systems such as satellite positioning

Motion

Acceleration / angular velocity

Measured by accelerometers, gyroscopes, and similar sensors

Light

Brightness value

Detected by a light sensor

How does a phone know whether it is upright or sideways, how bright it is, where it is, or how it is moving? It has different sensors inside that turn information about the physical world into data.

05Is data the same as reality?

No. This is one of the most important ideas in this article.

Data is only a representation of some information about the real world. It selects the parts we want to record and usually has limits on its precision and range.

A real tree

It has color, shape, smell, temperature, weight, texture...

Data in a computer

It might store only some details, such as a photo, location, and height

06Why must data be interpreted according to rules?

Because bits are only 0s and 1s. They do not automatically tell the computer what they represent.

01000001

As an integer

65

As ASCII

A

As raw bits

01000001

That is why data usually needs context: What type is it? Which encoding is used? What are its units and format?

ValueTypeUnitEncodingFormat

07Why is data so useful?

Once information has been converted into numerical data, computers can perform many kinds of operations on it in a consistent way.

Store

Save it on an SSD, hard drive, or memory card

Transmit

Send it over a network to another device

Copy

Make another copy of the same data quickly

Analyze

Programs can search, compare, and calculate

Compress

Use patterns to reduce the amount stored or transmitted

Encrypt

Protect data using rules from cryptography

What you have learned

  • Turning something into data means representing information we care about as values a computer can record and process, according to rules.
  • Numbers, text, images, sound, and video can all be encoded as data in different ways.
  • Physical properties such as temperature, location, motion, and light can be measured by sensors and converted into numerical data.
  • Data is not the real world itself; it represents some information about it.
  • Digitization usually has limits such as range, precision, sampling rate, and bit depth, so it does not automatically preserve every detail of reality.
  • The same bits can have different meanings; they must be interpreted using the data type, encoding, format, and units.
  • Once digitized, data can be stored, copied, transmitted, analyzed, compressed, and encrypted.
  • More precisely, “everything can become data” means that much of the information we can observe, measure, or describe can be converted using a suitable method.