The grade nine boys at Drakensberg Boys Choir School completed a maths project on the surface area and volume of 3D shapes.
Their final task was to build a container that could hold exactly one litre of water, for five minutes, without leaking.
The most structurally sound container, which had sides reinforced with pencils, was built by Alex Brits, Dian Botha and Luke Brown.
Sean Morrick, Owen Mngewu and Josh Naidoo also managed to build a waterproof container.
SEE THIS: Drakies making wishes come true
The other groups learned that it is not as easy as it looks to make a container waterproof.