Activities

It is known as a “substitution cipher” where you replace each letter of the alphabet with another letter by shifting the whole alphabet a certain number of letters.

• Try to encode your name with the Caesar Cipher by using the resources from the national geographic HERE.
• Work in pairs and send coded messages. Do not forget to give the number of shift or the letter substitution like A-X.
• Variations: write a message and give it to another team that need to crack the code without knowing the shift!
• Try the crack the code adventure from the national geographic website HERE
• Caesar code can be used to code a simple riddle, instructions, or clues if you are planning a Maths Trail or Treasure Hunt.

Morse code is a system for sending messages through dots, dashes and spaces. It can be used through many different mediums such as sound, light or on paper. It was first invented by Samuel F.B. Morse for the electric telegraph in the 1830s but, he had originally only used it for numbers so a man called Alfred Vail went on to develop it further to be able to code the English language.

In 1890 radios could not transmit speech, so using tones, Morse code was used to transmit over radio waves.

Morse code was still popular until the Cold War. Nowadays it isn’t used in commercial and military sectors but is still popular to learn and is needed for an Amateur Radio License.

• Read more about the Morse code on the cryptomuseum.com website
• Have a look to the dichotomic chart HERE from cryptomuseum.com. This chart helps you to understand how the Morse code of each Latin character is constructed. The letters with the highest frequency (i.e. the letters are used the most in English) are higher up in the table. A left-branch represents a dot, whilst a right-branch represents a dash. Ask the students which symbol should the letter L be represented by? If you go left, left, right which letter do you get and which symbol it is represented by? If you have a ‘Dash’, ‘Point’, ‘Point’, which letter do you get?
  
• You can also use the table HERE from cryptomuseum.com as guide to decipher our code (shortly coming)
• Algebra: .- .-.. –. . -… .-. .-
• Fractions: ..-. .-. .- -.-. – .. — -. …
• Morse code can be used to code a simple riddle, instructions, or clues if you are planning a Maths Trail or Treasure Hunt.

Binary code is a numerical system where everything is represented by either a 1 (on) or a 0 (off). When we think of the inventor of binary code we think of Gottfried Wilhelm Leibniz in the 17th century, but it has been traced back to ancient civilizations in Egypt and China.

Nowadays we use the binary system in computers but centuries ago it was used to keep records, for example, how much grain someone had.

So 0 will be 0, 1 will be 1. For the number two we use all our digit to we need to put 2 digits now. 2 = 10 and 3 = 11

To encode the 26 letters of the alphabet we need 5 digits. We can associate each letter with a number like its place in the alphabet A=1, B=2… For easy conversion from binary to decimal system each digit could be represented by an exponent of 2. So 11010 equals 16×1 + 8×1 + 4×0 + 2×1 + 1×0 = 26 | 10010 equals 16×1 + 8×0 + 4×0 + 2×1 + 1×0 = 18. Zero could represent a space if you are coding a sentence.

• Try to encode hello or your name in binary
• Try to decipher
• 01000 00101 11000 00001 00111 01111 01110
• 00100 00101 00011 01001 01101 00001 01100

We all know barcodes, we see them every day when we shop, and we don’t know where shopping would be without them. Supermarkets and shops need them for keeping track of inventory leading to cheaper prices and organised supply chain management.

They were first invented by Norman Joseph Woodland and Bernard Silver in 1949 but barcodes were not seen in stores until 1974 after the Universal Product Code (UPC) was put in place in retail. The UPC barcodes are a series of lines that vary in thickness representing an item with different digits under it. The famous first scan of a retail barcode was in Ohio in a Marsh Store.

Just before shops though the US rail industry used barcodes to mark railway freight cars, this shows us how flexible barcodes are and how they have so many different uses.

How to code a barcode?

The most commonly used barcode is the International Article Number (also known as European Article Number or EAN) with thirteen-digit: EAN-13. An EAN-13 has 4 components:

• the first two or three digits tag the country
• the following four or five digits tag the company/manufacturer
• the following four or five digits tag the product
• the last digit is the check digit

The Key or Check Digit

The check digit is an additional digit, used to verify that a barcode has been scanned correctly. The checksum is calculated as sum of products – taking an alternating weight value (1 or 3) times the value of each data digit. The checksum digit is the digit which must be added to this checksum to get a number divisible by 10. The mathematical equation will be:

Over the years with our modern world growing barcodes were no longer the best option, they were very limited in what information they could store so a gap in the market appeared.

A Japanese company Denso Wave were struggling with these limitations, some of their products could have 10 barcodes on them just to store the info they needed then. In 1994 employee Mashiro Hara was playing Go, a popular board game and came up with how the QR code could work. He realised how useful a grid system would be in storing information. They let the QR code tech be freely available for anyone to use and in 2002 Sharp released the first phone that could scan QR codes.

Then during the pandemic QR codes became even more popular with the need for a contactless world for example, a QR code to access a menu online.

Nowadays they can be used to mark attendance or access surveys online.

• Find a pattern activity HERE (soon to come).
• If this QR code is 25 pixels high and 25 pixels wide how many pixels is the QR code made up of?​

DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid) are two main types of nucleic acids made from different molecules called nucleotides (A, C, G, T, U).

DNA is the code of life and RNA converts this code into proteins to carry out functions in the organism.

In other words, you can think of a living being as a house. The blueprint for the whole house is the DNA. But it is inconvenient to use if you are only doing the kitchen. You have to take a closer look. How big is the oven? What colour are the cupboards? It will be your genes. Your kitchen will be different from your neighbour’s because the genes are different. But to look at the genes, you need a copy, an RNA – because you cannot rip them off the DNA. Then, from the copy, you can build the different equipment for your kitchen (the proteins).

History

For almost 200 years genes, their expression and their support (the DNA) have been researched starting with Charles Darwin and his ‘Evolution of Species’, a very controversial book during its time of publication.

We then saw Mendel discovering the basic idea of genetics when he experimented with pea plants and was the first to use the terms ‘dominant’ and ‘recessive’ genes.

In 1869, Friedrich Miescher was first investigating the proteins of white blood cells when he found a molecule that wouldn’t digest as easily as proteins and had high phosphorous content. He named this molecule ‘nuclein’. We know now this as DNA.

In 1944 Oswald Avery identified that DNA was responsible for hereditary calling it the ‘transforming principle’ which went on to inspire many other scientists including Erwin Chargaff who discovered how DNA is made up is specific to species.

In the 1950s Rosalind Franklin was working in X-ray diffraction, she was improving the X-ray crystallography at King’s College where she got a clear X-ray photo of DNA fibres. Using just these photos she was able to calculate the dimensions of the fibres and hypothesize that there were phosphates on the outside of a structure that was most likely helical. Before she got to fully finish her work two other scientists beat her to it using her photos. She unfortunately passed away only a few years later in 1958.

In 1953, James Watson and Francis Crick discovered DNA had a double helix structure, publishing their famous paper, which led them to win the Nobel Prize in Physiology or Medicine in 1962. Although Rosalind’s photos of DNA structure helped Watson and Crick majorly in their work, she received little to no credit until after her death. Although her co-worker Maurice Wilkins from King’s College went on to accept the Nobel Prize with Watson and Crick after her death.

Ada Yonath was the first person to map the structure of the ribosome, something many scientists had given up on – and for which she was awarded the Nobel Prize in Chemistry in 2009. She did this by crystallising and x-raying the bacterium Geobacillus stearothermophilus. It took her 25,000 attempts to do this without destroying the structure of the ribosome! This was a huge discovery and it allows us to fight bacteria with antibiotics that specifically target their ribosomes.

• 
  Morse Code
• L be represented by ‘left, right, left, left’ so .-..
• If you go left, left, right you get the letter U that is –.
• ‘Dash’, ‘Point’, ‘Point’ -.. you go left right right and you get the letter D

• Algebra: .- .-.. –. . -… .-. .- | Fractions: ..-. .-. .- -.-. – .. — -. …

• Binary
• hello: 01000 00101 01100 01100 01111
• HEXAGON: 01000 00101 11000 00001 00111 01111 01110

• DECIMAL: 00100 00101 00011 01001 01101 00001 01100

• Bar Codes
• The check digit of 978-0-306-40615-? is 7.
• No. The barcode is wrong. 51-68007-53219-3 is correct. You have to take away the reminder from 10 to find the correct check digit.
• 331-1027-64359-8 : (3 + 3×3 + X + 3×1 + 0 + 3×2 + 7 + 3×6 + 4 + 3×3 + 5 + 9×3 + 8) / 10 = 10y | 99 + X = 10y The nearest multiple of 10 that is equal to or higher than 99 is 100, so y=10 | X = 100 – 99 = 1
• 1100010 has a bigger space. It is encoded by 0.
• 7 areas for 12 digits = 12 x 7 = 84 + 3×2 (separators at the beginning and the end) + 5 (separator in the middle) = 95 areas!
• QR Codes
• There are 625 pixels on this QR code.
• DNA Codes