Activity Idea: Jenga Overhang

Activity Idea: Jenga Overhang

This challenge is to see how far you can get the furthest Jenga block to stick out beyond the edge of the table.  No tape, glue or any other materials can be used – just the blocks.  And it must be free-standing so no fingers used to counterbalance.

To make this work for a class / club, I recommend starting with 9 blocks for each team of 2 or 3 children.  There are 54 blocks in a standard pack, so you would only need 2 Jenga packs.  If you do have more, they can of course go on to create much more impressive structures. 

This doesn’t just entertain primary aged children – academic papers have been published on the maths behind the different types of structure.  These are worth a look for the images they include, which may spark off new ideas, either for you or the children. 

From 'Overhang' 2007 Mike Peterson & Uri Zwick

If you want to extend the activity you can include new challenges:

• furthest overhang where there is only one block on each level, ie a slanting stack
• highest structure with an overhang of one complete block – remember the blocks can go on end
•  if you double the number of bricks can you double the length of the overhang?  Can you predict how much overhang you could get with 3 times as many bricks? 

I recommend taking photos of the structures, as they are bound to be knocked down whether intentionally or by someone bumping into them.  

Another interesting way to record the work is to encourage the children  to create a lifesize picture the structure by drawing round a block as a template. This may help them visualise the physics behind what stays up and what falls down and enable them to plan new structures more effectively. 

There is also a simple interactive game which allows children to explore the concepts virtually on the excellent NRich website called ‘Tower Rescue’.

You will inevitably find some children want to be more creative rather than functional with their Jenga blocks.  And why not?  In 2009 there was an artwork at the Baltic Centre in Newcastle called ‘Overhang’ and visitors were encouraged to take inspiration and make their own artworks from bricks.  

Have fun!  And do please post pictures, whether of overhangs or other works of art.