Large quantities

Understand the meaning of bytes

Learn what the prefixes kilo-, mega-,
giga- and tera- mean

Practise converting between units

2

In this lesson you will:

2

We use nanometres to measure the
size of molecules.

We use centimetres to measure the
size of objects.

We use kilometres to measure the
distances between cities.

Why measure?

Why do we use different units?

Credit: The Galaxy (Chandra HST Spitzer): Wikipedia

Using different measurement
units and prefixes …

● Not specific to computing
● Common scientific practice

Why measure?

4

Credit: Four Metric Instruments: Wikipedia

5

Bits and Bytes

• Know the difference between bytes and hertz

• Understand what capacity and speed measure in what components

• Know the correct size order of bytes and hertz to yotta

• ...made up of 8 bits

• ...the base unit of capacity

• ...are measured by how many millions of instructions they can carry out in one second

• so a 3Ghz processor can carry out three thousand million instructions per second

• how many instructions are carried out per second

• how fast data can travel

• ... measured in bytes for capacity (how much data it can store

• ...measured in hertz for how fast it can transfer data between components

• ..measured in capacity for how much data it can store

• ...measured in hertz for how fast it can transfer data to memopryu

Part 2: Working with large numbers

• Be able to write large numbers in digit and word form

• Know how to convert measurements into bytes

• Use standard form to represent large numbers

• How many bytes in a kilobyte?

• How many zeros does it have?

• 1 kilobyte - 1,000

• 1 megabyte = 1,000,000

• Notice how many zeros

• Now finish the chart on OneNote - Bytes

• 10 minutes - come back at

Bits and bytes

Count the bytes in a couple of simple

problems.
Write the answers on your worksheet.

bits

bytes

÷8

⨉8

Bits, bytes, and prefixes
Unit conversions

bits

bytes

÷8

x 8

bit

b
binary digit
(0 or 1)

byte

B

8 binary digits

kilo

÷1000

mega

giga

tera

no prefix

÷1000

÷1000

÷1000

x 1000

x 1000

x 1000

x 1000

kilo-

K

thousands

mega-

M

millions

giga-

G

billions

tera-

T

trillions

What
does it
mean?

How
do I
convert?

What
does it
mean?

How
do I
convert?

Use these tables to translate:

200 bytes = 200 groups of 8 binary digits
1Mb = 1 Megabit = 1 million binary digits
10KB = 10 Kilobytes = 10 thousand groups of 8 bits

Use these graphs to convert between
units:

5GB = 5 ⨉ 1000MB = 5000MB
700MB = 700 ÷ 1000GB = 0.7GB
24Kb = 24 ÷ 8 KB = 3KB