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The World's Water Situation: A Science Demo for School or Home

Have you ever tried to reason with a kid about why they shouldn't waste water? "Why? It just keeps coming out of the faucet!" Just telling them not to waste it is probably about as effective as our parents telling us to eat our vegetables because there were starving kids in far off places. "So what? They won't get this food whether I eat it or not!"

Kids (and adults!) in developed parts of the world often take water for granted. We are lucky, unless we are experiencing a drought, to have a fairly consistent, clean water supply. This is certainly not the case everywhere.
by Scott Robinson
Let's look at 2 current events in the world's water situation. We've got some good news and some bad news. Then we'll explore a really effective hands-on way to educate about water conservation.

This post contains affiliate links, please see disclosures for more details. 

So first, the bad news... Have you heard about the toxic foam that forms on Bellandur Lake in India? I hadn't until I was assigned a writing piece on it. A combination of industrial waste and raw sewage has created a dire situation in this lake in the highly populated city of Bangalore. For decades pollution has been dumped in a series of canals that ends in Bellandur Lake. The winds and rain from monsoon season just add to the problem and make the foam build up. The foam flies through the air and builds up on the roads slowing traffic much like a snowstorm. It is giving people headaches, smells awful and sticks to your skin. Last May it even caught on fire! Lack of government funds, policing and environmental regulations prevent the problem from getting any better. Sort of a foamy nightmare.

The good news...An incredible young innovator has devised a plan to help clean up the Great Pacific Garbage Patch. Boyan Slat, a young Dutch entrepreneur and inventor, has an ingenious and cost effective plan in action to clean up a large portion of the bits of plastic that are floating, and breaking down, in the ocean. This plastic is slowly making its way into the food chain and causing human health issues, not to mention the devastation to aquatic wildlife as the trash floats around in the water. Slat's plan uses natural circular currents in the ocean, called gyres, to passively collect the plastic. It is corralled and collected, then recycled into oil to offset the cost of the collection. Amazing. Read more about his project, The Ocean Cleanup, here in the kid's article I wrote for DOGOnews.

So, there are negative things happening to the world's water, and some positive efforts to make changes for the better. The lesson for our kids is that although Earth is covered in water, very little of it is available for us to use. That is why we need to conserve what we have.

An effective hands-on way to show this is to do this demonstration at school or home. You can have students or your children help measure out the water in each step. Through the years I have come across many variations of this lesson. Here are two versions that I have adapted. One version is for those of you with access to science lab containers, like graduated cylinders, and the other version uses things you can more readily find around the house.

Version 1: The World's Water Demo with Materials from the Science Lab

  • 1000 ml graduated cylinder
  • 100 ml graduated cylinder
  • 10 ml graduated cylinder
  • petri dish (or any dish)
  • eyedropper
  • water
1. Fill the 1000 ml graduated cylinder with water. This represents all of the water on Earth.

2. Now pour 30 ml of this water into the 100 ml graduated cylinder. This represents Earth's fresh water. The remaining 970 ml represents the salt water in the ocean. We can't drink salt water!

4. Carefully pour about 6 ml of the "fresh" water into the petri dish. This represents the fresh water that is not frozen in ice caps or glaciers.

5. Of the water in the dish less than 1/3 represents water that is available above ground. Take an eye dropper and remove 1 drop of water from the dish. This represents the water that is clean, fresh, not polluted and otherwise available to use.

Version 2: The World's Water Demo with Materials from Home

  • 1 gallon jug
  • 1/2 cup measuring cup
  • 1 Tablespoon
  • eyedropper (or a straw to make a drop)
  • water
1. Fill the jug with water. This represents all of the water on Earth.

2. Take 1/2 cup of this water and pour it into one of the clear cups. This represents Earth's fresh water. The rest of the water in the jug represents salt water. We can't drink salt water!

3. From the 1/2 cup of water in the clear cup, take 4 Tablespoons of water and pour this into the second clear cup. This represents the fresh water that is not frozen in ice caps or glaciers.

4. From the cup with the 4 Tablespoons of water, remove one drop with the eyedropper or straw and put it in the third clear cup. This represents the water that is clean, fresh, not polluted and otherwise available to use.

Pretty mind-blowing, huh? Well there is good news here and there is bad news. The bad news is, we don't have a ton of available fresh water on Earth, so we need to understand how precious it is. The good news is we can teach our kids to conserve it!

For other ways to teach water conservation and test water quality, read my post: Science Teacher's Toolbox: Testing Water Quality

You might also want to check out Smarty Pants' TED-Ed video as a way to introduce water conservation!

Try these books to teach about water conservation! 


  1. Thanks for the great kids water conservation idea!

  2. You are very welcome! Hope it works out well for you! Thanks for stopping by the blog.

  3. You've written "From the 1/4 cup of water in the clear cup, take 4 tbs of water" - that's the same thing! This is an excellent resource, but how can I scale it properly?

    1. Thank you so much for pointing out that error! It should be 1/2 a cup instead of 1/4. (About 3% of the Earth's water is fresh, and there are 16 cups of water in a gallon.)