Classroom lesson · Kuang Si Falls - the turquoise waterfall · 🇱🇦 Laos

Kuang Si Falls - the turquoise waterfall

Bright blue-green pools stacked like nature's own swimming pools

The bright turquoise pools and white cascade of Kuang Si Falls surrounded by jungle

Photo · Wikimedia Commons

What is it?

Kuang Si Falls is a waterfall near Luang Prabang in northern Laos. What makes it special is the colour: the pools at the bottom are a dazzling turquoise blue-green, like liquid glass. The water tumbles down through a series of pools, each one slightly lower than the one above, like a giant natural staircase.

Tell me more

The water looks turquoise because it is full of a dissolved mineral called calcium carbonate. This mineral is invisible on its own, but it changes the way sunlight bounces inside the water - the result is that magical blue-green colour, especially bright on sunny days.

The pools are shallow enough to paddle in and the water is cool and clear. Around the falls, the jungle is thick with bamboo and enormous trees. Sun shines through the leaves and makes dappled patterns on the water.

The same mineral that colours the water also builds up on rocks and roots over time, coating them in a pale, stone-like layer. If you look carefully, you can see plants and fallen sticks that have slowly been turned to pale stone by the mineral-rich water dripping over them.

A bear rescue centre sits just next to the falls, where sun bears that needed help are cared for. Visitors can see the bears playing in large forest enclosures before walking up the path to the pools. The walk to the top of the falls takes about 20 minutes through jungle.

In the classroom

Walk your class through this in 15 minutes.

Talk together

Discussion prompts

01The water turns blue-green because of a dissolved mineral. Can you think of other times when an invisible ingredient changes the colour or look of something (like tea, or coloured ice lollies)?
02Why might having a waterfall and a bear rescue centre in the same place be a good idea for helping people care about nature?
03If you could design a nature area to protect, what three animals or plants would you put at the centre of it?

Try this

Classroom activity

Fill two clear cups with water. Add a spoonful of milk to one (calcium makes milk white). Hold both up to the light. Talk about what makes water look different colours. Then draw the waterfall pools as a cross-section from the side - show where each pool is lower than the one above.

Kuang Si Falls - the turquoise waterfall

Walk your class through this in 15 minutes.

Discussion prompts

Classroom activity

Other things that make Laos special

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