Obtain a date padlock (day / month / year), and set it to the exact date of a particular historical event. Use this to lock a chest, inside of which should be placed an illustrated sheet of information about the event in question. This sheet should clearly state that this needs to be read carefully, then brought to the teacher – who will then ask a series of questions about its content. Answering these questions correctly will be rewarded with a prize.

Next, place a label on the locked chest informing students that a fresh clue will be provided each day hinting at the correct combination, and that the first student to crack the code should bring the contents of the box to you to claim their prize. Place the box outside your room or in another suitable location where it can be accessed during break periods.

Between Monday and Friday, at the start of morning break, add a fresh clue onto or next to the box, making it progressively easier to crack the code. The first student to open the box will obtain the information sheet and should study it before bringing it to you. Ask the successful contender a series of simple questions to test what they have learned. Award a prize if they answer correctly: sweets for each correct answer to share with friends if you run the competition every week, or a larger prize like a book token if it’s a special event and if they answer all the questions successfully.

Case Study

The first time I ran the competition I prepared the following five clues ready for the full week:

  1. [Monday]: He was a graduate of Oxford University
  2. [Tuesday]: He wrote a letter to Hitler in 1939 trying to prevent World War Two
  3. [Wednesday]: The event did not take place in Europe
  4. [Thursday]: He believed in the power of nonviolent resistance
  5. [Friday]: The murder took place somewhere in Asia

However, I found (today!) that the challenge was a victim of its own success: with only the first clue (“This day saw the assassination of a major political figure”) several students crowded around the box and, using their mobile phones, tried an endless amount of possibilities (John F. Kennedy, Abrham Lincoln, John Lennon, Martin Luther King…) until they finally hit upon the correct answer and brought me the information sheet the same Monday morning!

Therefore, for the next competition  I changed the rules slightly:
The box can only be handled when I am in my classroom during break.
Any student can only have a maximum of 30 seconds trying to crack the code per breaktime.
I also changed the questions to avoid giving too much away too early on.

Taking it further: Multiple Padlocks!

A second approach I have tried – and which I now prefer – involves adding several padlocks to the box. Each day, a new clue is provided, the answer to which will unlock one of the colour-coded padlocks (although students have to work out which one!).

When the final clue is made available, any student trying to open the box has to do so in my presence and will have 60 seconds to open all of the locks.

If they fail, they will not be allowed to try again for a minimum of 5 minutes: so they need to be sure to have answers ready!

If they succeed, they are then asked some simple factual questions based on what they have hopefully learned by researching the answers to the puzzles. Correct answers to these questions wins the prize!

The following examples of clues gives a clear idea of how the format works. I’ve also made a habit of running each picture through a filter in my image editing software to stop students simply taking a photo of it and uploading it to Google Image search to find out what’s being shown!