7 Surface Tension Experiments To Try With Kids

Dianna Cowern experiments - Surface tension experiments for toddlers and kids to learn about the phenomenon of liquid surface tension.

Here is a list of easy and fun surface tension experiments for kids. These surface tension experiments with water can help kids learn about static water and the forces within it.

Do you love the 4th of July milk fireworks?

What if you can create them using milk?

Have you noticed crazy little balls in your coffee mug while stirring it?

Well, it’s possible to recreate them! There are lots of other factors to know. So, let’s have a look at the seven science experiments that will help to understand physics in a better way while having fun at home.

Surface Tension Experiments for Kids

1. Milk Fireworks       

This is an easy science activity that needs only a few raw materials and can prove to be a great boredom buster. 

Raw materials 

  • A dish 
  • Milk
  • Food coloring agents 
  • Liquid dish soap
  • One earbud

Required Steps 

  • Take the dish and pour some milk into it.
  • Now drop a few drops of coloring agents in the middle.
  • Now take an earbud soaked in liquid dish soap and dip it into the middle with food coloring agents. 
  • The colors get scattered in all directions like fireworks! 
Milk Fireworks Experiment - surface tension experiment
Courtesy: Physics Girl


Experiment Observing that adding little soap to the milk weakens its surface tension by pushing the milk molecules with its hydrophobic ends. Also, the food coloring agents are pushed along with them, and end up having a spectacular sight of fireworks on liquids!

Note: You can conduct this experiment with milk at different temperatures such as warm and very cold to see whether this will make any difference to the behavior of the milk molecules.

2. Water BBS

This experiment demonstrates how crazy little balls notice in the coffee mug while stirring it.

Water BBS Experiment - surface tension experiment
Courtesy: Physics Girl

Raw materials 

  • One cup of coffee
  • One coffee stirrer
  • Few drops of liquid soap

Required steps

  • Take the coffee mug and stir it with the stirrer
  • Maybe nothing will happen, and then mix a few drops of liquid soap


In this experiment, notice some little balls in the coffee mug, which are nothing but anti-bubbles. These bubbles are formed when a liquid is dropped turbulently into the same or another liquid.

These are thin films of gas enclosing a sphere of liquid that can appear and then get fully submerged in the liquid.

Unlike ordinary air bubbles, these anti-bubbles do not rise quickly on the top. Patient to see them as they are quite mesmerising.

3. Soap Boat

This science activity video on a soap boat experiment is all about the surface tension of water and the impact of soap on water.

Water Boat Experiment - surface tension experiment
Courtesy: Physics Girl

Raw materials 

  • 1 dish containing water
  • 1 little boat with a notch out of a card
  • A few cotton buds
  • Liquid soap

Required steps

  • Take the dish and place the little paper boat on the surface of the water
  • Now, soak the cotton bud in liquid soap and touch its tip into the water to power your paper boat


In this experiment, the boat will start moving swiftly! Now, this happens when you touch the soap on the surface of the water. Soap weakens its surface tension and creates enough force to push the lightweight paper boat. Interesting to notice it!

4. Floating Card

This science activity video on a soap boat experiment is all about the surface tension of water and the impact of soap on water.

Float Card Experiment - Surface tension experiment
Courtesy: Physics Girl

Raw materials 

  • 1 open jar with a mesh screen on its mouth  
  • 1 card 
  • 1 jug of water

Required steps

  • Take the open jar with the mesh screen and pour water into it from the jug
  • Now, take the card and place it gently in the mouth of the jar
  • Invert the jar, and you will see that it will uphold the card!
  • Next, gently remove your hand from the card
  • Slid out the card from beneath the jar
  • The jar will hold up the water mysteriously!


Observations help to notice the mysterious water suspension. So, the science behind this floating water trick is nothing but the surface tension across the screen, which holds up the water.

There is also a role of cohesion to play in this science activity. It is the cohesion that causes surface tension. Here, water molecules remain joined together between each tiny opening of the screen mesh and form a thin invisible membrane that is strong enough to hold the water when the jar is inverted.

You can even stick some needles inside the jar! Interestingly, the surface tension will successfully prevent the water from falling in that case too! 

You can use this experiment as a magic trick before your friends and can, later on, explain to them the science behind the water suspension.

5. Suddenly sinking paper clips

This science activity video on paper clip floating and sinking is again about the surface tension of water.

Suddenly Sinking Paper Clips - surface tension experiment
Courtesy: Physics Girl

Raw materials 

  • 1 glass containing water
  • 1 paper clip
  • 1 piece of tissue paper
  • 1 Q-tip
  • A small quantity of liquid soap

Required steps

  • Take the paper clip and place it on top of the water surface of the glass
  • Try to balance it on the water surface
  • If it sinks, take it out from the glass
  • Now, place the piece of small tissue paper on the water surface and then put the paper clip on it
  • Next, gently remove the tissue paper from beneath the paper clip as it will start floating on the water surface
  • Now take the Q-tip and soak it in liquid soap and touch its tip into the water
  • The paper clip will again sink at the bottom! 


Now, wondering why is the paper clip floating on water soap? Well, the reason is again the humble surface tension! 

In the second step, then try to make the paper clip float on the water surface, it sinks because the metal with which the clip is made is denser than the water. 

However, when placing it on a piece of floating tissue paper, it does not sink because now the surface tension of the water is supporting it.

Again, when you touch the water with soap, this surface tension gets reduced. So, the clip sinks like a brick into the glass. 

Also, let’s experiment with this interesting activity with different lightweight objects to see whether the same thing is happening again. 

6. Penny Dropper

Have you ever wondered how many drops of water can fit on a penny?

Well, this super fun science activity will give all the answers. 

Penny Dropper Experiment - Surface tension experiment
Courtesy: Physics Girl

Raw materials 

  • 1 plastic dropper 
  • 1 penny
  • Some water

Required steps

  • Take the penny and place it on a flat surface
  • Now take the dropper, fill it with water, and put a drop of water at the center of your penny
  • Keep on adding water drops to the penny and count
  • A dome shape made up of water drops will form on the penny 


The experiment makes us observe that a penny can hold several water drops before it eventually starts spilling over the coin. Here, it is the surface tension of water that prevents the water molecules from falling apart.
So, the water molecules remain together and form a dome shape.
Even Experimenting with other liquids such as saltwater, milk, and soapy water to figure out whether they yield the same result or not.

7. Leidenfrost Effect        

Have you ever heard about the Leindenfrost effect?

Well, it is a phenomenon where liquids, instead of getting evaporated, glided on the surface of a pan. This happens when the pan is heated beyond the boiling point of that liquid. 

This effect was named after the German doctor Johann Gottlob Leidenfrost (1715-1794), who described this effect. 

However, to do this exciting science experiment, you will need adult supervision as this involves heat hazards! 

Liedenfrost Effect Experiment - surface tension experiment
Courtesy: Physics Girl

Raw materials 

  • 1 empty pan
  • Some water
  • One dropper

Required steps

  • Take the empty pan and put it on a stove.
  • Next, add some water droplets into the pan one by one with the help of the dropper, and the water droplets will quickly evaporate. 
  • Keep on adding the water droplets but now increase your speed. 
  • Water droplets will now not evaporate. They will instead make small spheres gliding on the hot surface of the pan.


The observation makes us wonder how does water dance on a hot pan. See, when heating the pan more than the boiling point of water, which is 100-degree Celsius, water drops vaporize quickly that it forms a layer of steam that insulates the rest of the water droplets are added from the hot surface of the pan. As a result, you end up watching the dancing water droplets. 

All the above activities can be done at home to develop a better understanding of some key concepts of physics. 


Dianna Cowern, also called physics girl presented a video of seven experiments or science tricks that offer surface tension, anti-bubble, cohesion, and lienenforst effect.

Courtesy: Physics Girl

7 Experiment to understand physics - Surface Tension Experiments








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