Science Experiments with Water for Preschoolers

Are you looking for easy science experiments for preschool children? These simple Science experiments all use water! Fun Science experiments are the perfect way to introduce your little learners to the Scientific Method and important concepts. I love a simple experiment that uses common household items. Your little scientists will love these fun ideas!

Note: It is important to provide children the opportunity to perform a preschool science experiment over and over again. For young children it is crucial that they are allowed to do the experiment themselves and that they are given time (over plenty of days) to try it over and over again.

Tip: If there is something in your experiment that makes you nervous as the teacher or parent to hand over to young kids, then find simple ways to adjust your experiment. For example, if your fun water experiment calls for a glass jar and you are worried about them breaking, look at where you are performing your experiment to eliminate the jars being bumped and knocked over or use a clear plastic container.

Will It Dissolve?

Will it dissolve in water?


  • clear plastic or glass cup
  • craft stick
  • water
  • Ingredients to Test: baking soda, flour, sugar, oatmeal, pepper, tea, coffee, parsley (or similar spice)


  1. Each child fills their cup half way with warm water. (I have a pitcher of water on each table for the children to pour their own.)
  2. Take a pinch of the ingredient you are testing. Drop it into the water.
  3. Use the craft stick to stir the water.
  4. Observe what is happening. Does the ingredient dissolve in water? Or can you still see it?

Color Changing Flowers

This experiment is fun to set out on a shelf or table and let the children observe and talk about it during the school day. I love science activities for this age group where they can try the experiment or observe it as often as they want to.


  • cups or vases
  • water
  • food coloring
  • flowers or celery


  1. Set out two or three glasses or vases. Fill each one half way with water.
  2. Add a few drops of food coloring to each glass.
  3. In each cup, put one white flower (carnations work well) or a large piece of celery.
  4. Observe over a few days what happens to the water and what happens to the flowers or celery.

Sink or Float?

Cool science experiments don’t need a ton of preparation or materials. This simple sink or float experiment never gets old, no matter what the age of the children are.


  • 2 Containers
  • water
  • Objects to Test: ball, egg, toy, crayon, orange, pencil, etc.


  1. Fill two containers of water. They can be large storage containers or mixing bowls.
  2. Take turns putting an object into the container. Does it float on top of the water or sink to the bottom?
  3. Pull the object out and try something new.

Tip: I’ve tried having the children sort the objects into two different piles – a pile for objects that sink and a pile for objects that float. However, it took away from the experience and wasn’t necessary. They are gathering the information they need, making predictions, and drawing conclusions as they try different objects. You want to embrace the moment of curiosity instead of distracting from it with a sorting activity.

Traveling Colors

Here’s a cool way to experiment with absorption. For this classic experiment you will need:

  • 2 cups of water
  • food coloring
  • paper towel


  1. Put several drops of food coloring in one cup. Stir the colored water.
  2. Color the second cup with a different color. Stir.
  3. Set the two cups of different colors next to each other.
  4. Put a paper towel strip between the two cups. One end of the paper towel will be in each cup of colored water.
  5. Watch as the water moves up the paper towel. Your students will have fun learning about absorption.

Coffee Filter Art

This Science activity is also art! They look beautiful hung up together.


  • coffee filters
  • washable markers
  • spray bottles
  • water


  1. Draw lines, a design, or even scribbles on a coffee filter with washable markers. You don’t have to cover the whole coffee filter with color. It is ok to have white space showing.
  2. Spray the coffee filter with water.
  3. Watch the colors move and blend.

Walking Rainbow

Check out this easy experiment that is fun to try over and over again.


  • 2 jars or cups
  • water
  • paper towel
  • washable markers


  1. Fill a cup with water.
  2. Fill a second glass of water and set them next to each other. Make sure the water level is close to the top. You only need simple ingredients so you will be able to try it right away.
  3. Take a strip of paper towel.
  4. On one end, color your own rainbow. Use washable markers. Color a small square of each color (red, orange yellow, green, blue, purple) on both ends of the strip.
  5. Bend the paper towel into a curved, rainbow shape.
  6. Set each end into the jars of water at the same time.
  7. Watch what happens with the paper towel and to the water inside the jars.

Water Play

Use a water table or big bins for water play. Incorporate funnels, turkey basters, a measuring cup of each size, spoons, plastic bottles, etc. You can put empty jugs, containers, and cups with it too. Offer jugs of colored water.

Through this water play, children will be experimenting with and discovering which holds more, what sinks or floats, and color mixing. They will also be building hand-eye coordination and fine motor skills.

Shaving Cream Cloud and Rain


  • jar
  • water
  • shaving cream
  • food coloring
  • pipettes


  1. In a mason jar, fill 3/4 of the way full with water.
  2. Fill the rest of the jar with shaving cream.
  3. Use pipettes to transfer colored water to the top of the clouds (shaving cream).
  4. How much water can the cloud hold before it starts to rain (into the bottom of the jar)?

Oil and Water

This is one of my favorite classic science experiments.


  • plastic cups (saves on cleaning time)
  • vegetable oil
  • water
  • food coloring
  • pipettes
  • alkaseltzer (optional)


  1. In a plastic cup, pour it halfway full of vegetable oil.
  2. Fill a cup of water and add food coloring. Stir
  3. Use a pipette to add drops of colored water to the cup of oil.
  4. Watch what happens.
  5. Turn it into a lava lamp by adding a half tablet of alka seltzer to the cup. This creates movement in the liquid that children are in awe of.

Variation: Switch the experiment around and use the pipette to add drops of oil into a cup of water. What happens? How is it different than the first experiment? How is it the same?

Variation: Drop different liquids into the oil to observe what happens. Try dish soap, vinegar, or a juice that you have on hand. Do they mix? Do they separate?

Tip: Collect used water bottles (small ones) for this experiment. The children will love shaking the liquids and then watching them separate.

Growing Colors

This water Science experiment is so much fun. I love that it is open ended so children can dive right in and give it a try.


  • paper towel
  • water
  • food coloring
  • pipettes


  1. Lay out sheets of paper towel to cover your work surface.
  2. The amount of water that you offer is important in the set up of this activity. Use a small, shallow bowl so that they will use the pipettes instead of picking up a cup and pouring it.
  3. Put several drops of food coloring in the water. Stir.
  4. Use pipettes to transfer drops of colored water to the paper towels. This is great for fine motor skills.
  5. Observe how the water spreads along the paper towel. This is a fun way to experiment with absorption.
  6. See what happens when two colors touch.

Water Cycle in a Bag

This simple water experiment is also great for Science projects with kids of all ages. It is a great way to see the water cycle in action.


  • clear plastic bag
  • water
  • marker
  • blue food coloring


  1. Draw a rain cloud at the top of the bag. Also, add a sun at the top.
  2. Fill the bottom portion of the bag with blue colored water. This represents the puddles.
  3. Seal the bag and tape it in a window that gets sunlight.
  4. Watch how the water moves from the puddle to the top where the clouds are and then back down again.

This Earth Science lesson can be observed over and over again. Add vocabulary such as evaporation and precipitation when appropriate.

Here’s an Ice Cube Experiment from Preschool Inspirations that focuses on how to melt an ice cube.

Download the 12 Preschool Science Experiments with Water.

I hope you love these preschool science experiments with water as much as I do. Science is everywhere! Even with simple ingredients, children can explore, experiment, and learn new things. Remember, if the experiment seems too messy see how you can adjust it so that you aren’t worried about the mess as the children are experimenting. Maybe it’s having towels close by to soak up any spills or using plastic instead of glass. There are so many simple changes that can be made to make these experiments work in any classroom with young children.

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