A classroom activity that involves students encoding and decoding data can involve a teacher generating an Arecibo Signal using an online generator. The binary bit sequence used to generate the symbol can be provided to students in audio form without anymore of an explanation than “We have been asked by an alien intelligence agency to decode this message”.
The steps involved in decoding will depend only on the group of student’s knowledge on ciphers and techniques to decode the ciphers using the skills they have gained throughout their schooling career. The students then use any available on-hand digital resources and knowledge they can to gather data, and convert it into information that will aid suggesting the next step to decode the cipher.
Once all group believe they have solved and decoded the cipher, they all present to the class. In the presentation includes the result of the decoded cipher in image form and the steps each student took in order to solve the problem. At the end, the teacher displays the correct result of the decoded cipher and the steps that were taken to go from encoded message to decoded message.
(Image sourced from https://www.wolframcloud.com/objects/demonstrations/AreciboSignalGenerator-source.nb)