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12 Simple Water Experiments for Preschoolers

Here are some fun water experiments for preschoolers to help kids discover its properties, how it changes, and its effects on other substances.

Water surrounds us. We see it everywhere in nature, and it hides within the pipes of our homes until we open a tap and let it flow. Water is essential to support a healthy environment and healthy bodies. 

Because of water’s far-reaching importance in our lives, we want to make sure that young children have many chances to learn about its significance.

Use these science experiments with water to expand kids’ vocabulary. They are the perfect opportunity to introduce children to new words and science concepts such as:

  • Solid 
  • Liquid 
  • Absorbing
  • Dissolving
  • Suspension
  • Density
  • Buoyancy 
  • Porosity

…and lots more.

Wade right in, testing the waters while watching the fun!

12 simple and fun water experiments pin image

1. Water Exploration Station

Outdoors or inside, set up a large tub or well-supervised kiddie pool partly filled with water. Add an assortment of plastic containers for pouring, including funnels and colanders. 

Children learn a great deal about the properties of water just by experimenting on their own. They also learn early maths concepts such as capacity and volume.

Keep towels handy to dry off your young scientists!

2. Mix-Up?

Fill a large, clear container with equal parts of water and oil (cooking or baby). 

Challenge kids for guesses (“hypotheses”) about what could happen when the materials are combined. 

After observing how the water and oil do not mix, ask for ideas of why that is the case, which includes the heaviness (“density”) of water. 

water and oil in a cup

Introduce food colouring and discuss whether that is most like the oil or the water. Drop the colouring into the liquid mixture with a pipette or eyedropper. 

Discuss the results and what those tell us. Introduce the term “suspension” for liquids that do not mix in this oil-water experiment.

3. Solid to Liquid

Give each child a clear, plastic container to which they add fine table salt with a spoon for this simple water experiment. 

With pipettes, ask them to start adding small amounts of water. They can observe the salt turning a bit darker as it soaks up (“absorbs”) the water. 

As they stir, kids also see that the salt looks like it is melting  (“dissolving”) and forming a “solution.” 

Try the same experiment with coarser salt crystals. How does the process of dissolving differ? 

Try the salt-water experiment with water of different temperatures as well. Does anything change in the process?

4. Exploring with Ice Cubes

Remind children that the cubes are not to be eaten or placed in their mouths since these are a choking hazard. 

Offer ice cubes (water in a solid form) and an assortment of plastic containers for kids to stack/build, stir and pour. 

Discuss: 

  • What starts to happen with the cubes? Why? 
  • Outdoors, is there a difference in the results when working in the shade or in the sun?
  • Why is the ice melting? 

Then have them add ice cubes to separate containers of cold and warmer water. 

  • What is the difference in the results?

5. Sink or Float?

Set up a basin or tub partly filled with water. Offer a variety of small objects like corks, paperclips, ice cubes, fabric, coins, pencils, marbles, cotton balls, bar soap, and crayons. 

Ask children to predict for each object whether it will sink or float in the water and then give it a try. 

Ask why they think the object is either floating or sinking in the water, which leads to a discussion on “buoyancy” and “density” or heaviness. 

6. Changing the Shape of Water

Fill plastic measuring cups with equal amounts of water, which may be tinted with food colouring. 

water in containers with food colouring

Children pour those amounts of water into different shapes and sizes of containers. They observe how the same amount of water looks very different in various containers. 

Ask for their ideas of why they think it works this way.

7. Oops, a Water Spill!

Talk about what kids and parents grab when water or other liquid spills. 

Why do we use those materials? Discuss the word “absorption.” 

Set out low tubs of water and various objects to test: sponges, paper towels, socks, foam letters and washcloths. 

Have them place one object at a time in the water and then squeeze the soaked-up liquid into silicone muffin cups that have been labelled for each.

little girl squeezing' water out of wash cloth

Which materials absorbed the most or least water? Ask them why they think it worked that way. 

Introduce the science concept “porosity” related to some materials being more “porous.”

8. Pushing Water Out of the Way

Set up a clear container partly filled with water. Mark the current water level on the side. 

Before asking kids to place objects into the water, ask them to predict what could happen. 

Then, have children add one stone or other object at a time to observe what happens to the water level. 

After observing the rise in the water level, see if they can guess that the water is being pushed out of the way, or being “displaced,” while it makes space for each object being added. 

9. Rainbow Water

On a sunny day, set out a clear container of water and a sheet of white paper. Place the water so that sunlight shines through it onto the paper to observe the rainbow.

Lead children into the understanding that rainbows occur when sunlight shines through water, just like they have seen on rainy days when the sun peeks out. 

The light is “refracted” or separated into different colours, appearing as a rainbow. Teach them the colours with these rainbow songs.

10. Learn About Erosion

Outdoors or on a sand table inside, form a mountain of dirt or sand. Pour water slowly onto the mountain and observe what happens. 

child making a hill with sand

Do you see differences if the water is sprinkled or poured more quickly? Do you observe differences when using sand vs. dirt? 

Explain to children how this is like real-life “erosion” from rains and floods.

11. Easy Evaporation

Fill a clear plastic cup with water and draw with a permanent marker at the water level line. Place it in a sunny window. 

Mark the new water level each hour to track the “evaporation.” 

Kids could guess that the heating of the water from the sun contributes to the evaporation, which is the liquid water turning into a gas, referred to as “water vapour.”

12. Water Cycle in a Bag

Take the idea of evaporation a step further by adding the water to a sealed plastic bag instead of the open cup in the previous experiment. 

Before adding the water, clouds may be drawn with a permanent marker near the top and grass and flowers near the bottom. 

Tape the bag to a sunny window and watch the evaporating water “condense” and stick to the sides and upper area of the bag, much like clouds. 

The water eventually comes back down just like rain!

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Last but not least, be sure to check out your local library for picture books about water. Hey, Water! by Antoinette Portis (2019) is a great place to start. 

Scroll down at this library website for family-friendly tips to accompany the book. 

If you need more ideas or if your preschool theme is about water and rain, check out these fun rain activities too.

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