Year 9 Logic

• Computing
• Lower Secondary (Key Stage 3)

Year 9 Logic/legal issues

By the end of this lesson you will understand:

• Logic gates
• Truth tables
• How to create a logical circuit

Why are we learning this? Logic gates aren’t just for computer chips, from your phone to cars to robots, every modern technology relies on logic gates. Here are real jobs that use logic gates or Boolean logic every day:

Computer & Hardware Engineers:

• Use logic gates to make decisions inside chips (CPUs, GPUs, etc.).
• Example: A CPU checks conditions like (A AND B) to run instructions.

Electrical & Electronics Engineers:

• Use logic gates in control panels, traffic lights, and security systems.
• Example: A motor runs only if “Start” AND “Safety switch” are both on.

Robotics and biomedical Engineers:

• Robots use logic gates to combine sensor data (e.g., move forward if path clear AND battery full). Pacemakers and other life saving equipment.

Software Developers:

• “If score > 100 OR lives = 0, then game over.”
• Logic gates → If...Else statements in programming.

Automotive and aerospace Engineers:

• Logic gates control airbags, braking, take off, landing and lights.
• Example: Airbag activates if (impact sensor = 1 AND seat occupied = 1).

🏭 Automation Technicians

Set up machines and robots in factories.

🔁 Use Programmable Logic Controllers (PLCs) that rely on logic gate conditions.

🚀 Aerospace Engineers

Ensure aircraft and rockets behave safely.

✈️ Logic gates check multiple safety inputs before takeoff or during flight.

🧬 Biomedical Engineers

Design devices that monitor and respond to the human body.

❤️ Example: A pacemaker uses logic-like circuits to trigger a heartbeat when needed.

💬 Why It Matters

Logic gates are the building blocks of digital decision-making.

From your phone to cars to robots — every modern technology relies on logic gates.

What is a truth table?

• A table of the outputs from all possible combinations of input.

Teacher input

Logic:

• it is raining and I have an umbrella? wet/dry
• it is raining or I have an umbrella? wet/dry
• it is raining, no umbrella? wet/dry

Computers store and process binary (1s and 0s)​

ONE (1) is TRUE and ZERO (0) is FALSE​

They make decisions using logic gates​

Each gate takes input(s) and gives an output​

Teacher input

The three main logic gates are…​

AND – Both inputs must be TRUE to give TRUE​

OR – Either input can be TRUE to give TRUE​

NOT – Reverses the input. (TRUE gives FALSE & FALSE gives TRUE)​

Teacher input

This programme is called Logic.ly it allows us to make circuits online.

I do

I do

I do

I do

Which gate gives a 1 output if either input is 1?​

1. NOT
2. OR
3. AND
4. NAND

We do tasks:

• Combine gates A AND (NOT B)) – work out the output and draw a truth table.​

Refine:

A	B	O
0	0	0
0	1	0
1	0	1
1	1	0

Modify task

make the following circuit and their truth tables in Word:

• A OR (NOT B)

Success criteria:

• Have all four inputs listed correctly.

0	0	?
0	1	?
1	0	?
1	1	?

Independent task make the following circuits and their truth tables in Word:

• (NOT A) AND (NOT B)

Stretch:

• (A OR B) AND (NOT C)
• (A AND B) OR C
• ((A OR B) AND (NOT C)) OR D

• Ethical – What is morally right or wrong (e.g. privacy, fairness)​
• Legal – What the law says (e.g. copyright, GDPR, hacking laws)​
  
• Cultural – How different groups, communities or countries are affected​

​

What’s an example of technology causing an ethical issue?​

• Should companies be allowed to track everything we do online?​

• What law protects people’s personal data?​

Should companies be allowed to track everything we do online?

What law protects people’s personal data?​

A company uses AI to filter job applicants, but it tends to reject certain names more than others

1. Ethical issue​
2. Legal issue
3. Cultural issue

A company sells your data without telling you
Using copyrighted images on a YouTube video without permission
A robot replaces factory workers in a small town

Ethical

Legal

Cultural

Choose one of the following scenarios:

• A school uses facial recognition to take attendance.
• A company fires workers and replaces them with machines.
• A student downloads music without paying.

Answer:

• What type of issue is this (ethical, legal, cultural)?
• Who is affected by this?
• What could have been done differently?