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 minutesWhy 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.

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.