Cracking Codes Lesson 1

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.