**Cracking Codes Lesson 1
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**Introduction: 5 minutes** – Use a Morse Code Generator to play some (very slowed down) messages for students to decode. Discuss why this is was a good way to transmit data in the past.

**Brainstorm: 5 minutes**** – **Why are codes important? Who uses them? Why do mathematicians go into this career? Look at all data transmission – TVs, internet, mobile phones. Discuss the picture at the top of the page – this was transmitted from Mars – which is on average 225 million km from Earth (why on average?) So, how can we transmit data across such a huge distance?

**Video: 10 minutes:** Watch Marcus De Satouy video explaining codes (stop around 8.30):

**Worksheet: Between 30 mins and 50 minutes depending on ability and hints – **Give out code challenge worksheet – Murder in the Maths Department. Working in groups of 2-3. Students will probably need direction – but try to limit this to a minimum to encourage problem solving. (First students to finish should create their own coded messages for each other).

**Lesson 2:**

**Binary Codes Introduction: 5 minutes** – Can we see the link between binary codes and Morse codes? Why are binary strings good for sending data? Link back to Mars picture. Talk about SETI – what is SETI (Search for Extra-Terrestrial Intelligence), what do they do? (Scan sky looking for non-random data strings)

**Binary Code Worksheet: 25 minutes **– Students need to convert the binary string codes into pictures.

**Extension material: 25 minutes – **Handout Vigenere Cipher, ISBN codes and Credit Card Codes for top ability students

**Lesson Resources:**

Large Code Challenge Resource Pack (including Binary code and Vigenere Cipher Worksheets and Murder in the Maths Department) for download on TES.

**Additional Resources:**

Crypto Corner is the newest and best code making and code breaking website online – it’s got a huge amount of code information and also allows you to generate your own codes.

CIMT Code resources – a fantastic resource with a large number of ready made worksheets and teacher notes on lots of different codes.

Secret Codebreaker also has a lot of information about different codes

Counton website to generate different codes – generate your own codes

Nrich has a nice article about the history of codes and mathematics

NASA codes from the stars – more explanation on binary string codes.

Khan Academy code breaking videos– a large number of short videos looking at both codes through history and more modern code methods.

Numberphile video on public key encryption using prime numbers.