What makes water molecules stick together to form a drib of h2o?

Surface Tension.

What is surface tension - two droplets of water on purple background - Kids Activities Blog
Surface tension keeps the water aerosol together on a surface like this fleece.

What allows those cool water bugs to walk on water?

Surface Tension.

What is surface tension - bug walking on water - Kids Activities Blog
Surface tension allows the bug to walk on water without falling in.

Surface Tension

But what is surface tension and how to you teach information technology to children in a style that makes more sense?

The property of the surface of a liquid that allows it to resist an external forcefulness, due to the cohesive nature of its molecules.

–Water Scientific discipline Schoolhouse at USGS

I think of information technology a little like a "pare" that forms on the surface of the water to keep the edges of the h2o together even though that isn't quite right scientifically. Basically, the water molecules are more attracted to each other than they are the air.

This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.

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Surface tension of water droplet coming out of faucet - Kids Activities Blog
Water drops want to be round, merely when dropping gravity gets in the way.

Surface Tension and Droplets

Because water molecules are attracted to each other, this causes the shape of a liquid droplet. They want to be spherical to be as close to each other as possible, only when dropping gravity starts pulling them abroad from each other.

water bugs can walk on water because of surface tension - Kids Activities Blog
H2o bugs weight is non heavy enough to pierce the water's surface tension.

Surface Tension and H2o Bugs

In the instance of h2o bugs and other insects like water striders who are able to run on the water surface, their weight is not plenty to penetrate the surface of the water caused by tension.

Surface tension and floating - leaf and bug floating - Kids Activities Blog
Things that are also heavy to float tin can float until the surface tension is disrupted.

Surface Tension and Floating

Some objects tin can float on the surface of water, even though they are denser than water.

safety pin floating in water due to surface tension - Kids Activities Blog
Floating pivot experiment works because of surface tension.

An object like a safety pivot or needle tin carefully be placed on the surface of the water and float even though information technology is quite heavy in relation to the water. One time the surface is agitated and the surface tension "broken" the object volition quickly sink.

Hands-On Surface Tension Learning Activeness for Kids

Well, I wouldn't get more than 10 words of that definition spoken before my children'due south eyes would glaze over.

So I decided to forget the formal definitions and instead practice a hands-on demonstration!

what is surface tension

Supplies Needed

  • penny
  • clasp bottle, medicine dropper or pipette
  • h2o

To demonstrate surface tension, we used a penny and found a squirt bottle that we could hands command the rate of water droplets.

A medicine dropper or pipette would be ideal.

Activeness Directions

water drops on penny

Footstep ane

Fill your clasp bottle, dropper or pipette with water.

Pace 2

Drop water onto a flat penny drop by drib.

We filled the acme of the penny with water drops….and then nosotros added more drops….and more drops.

Every bit my children worked on adding drops of h2o to their pennies, I explained to them what surface tension is in my own words:

The water molecules concur on tightly to each other. They don't want to split up. They specially cling to each other at the surface considering there is no water molecule on the other side of them to grab on to. The h2o molecules on the surface holds on to each other so tightly that a "pare" seems to grade on the surface. he water aerosol keep building on peak of each other until a pocket-size dome of water forms on the top of the penny.

Of class, the moment eventually comes when the water molecules just tin can't hold on whatsoever longer and they spill over on to the table.

water molecules hold on tightly

My children were absolutely amazed with the dome of water they created on their pennies.

Withal, they repeated the demonstration over and over over again non to come across the dome but to run across which one of them would make the h2o spill on to the tabular array first.

What fun nosotros had!

Surface Tension Activities for More Learning

Try some of the activities in the surface tension information above like trying to make a needle or safety pin float then sink. Go on a water drop scavenger hunt and try to find places where water is a sphere and where water is a droplet shape. Notice things floating that seem to heavy to bladder!

More Science Activities & Uncomplicated Science Experiments from Kids Activities Weblog

  • Check out this surface tension experiments idea using LEGO bricks.
  • Here is the surface tension experiment using pepper.
  • Explore the surface tension created with how to make bubbles.
  • Explore the surface tension colorful results in this milk and food coloring experiment.
  • Surface tension goes a little crazy with how to make oobleck!
  • 100s of science experiments for kids that you can easily exercise in your kitchen.
  • More than uncomplicated science for kids at domicile.

What did you larn nearly surface tension? How did your surface tension activity get?

Kim is a homeschooling mom of two children. When she isn't on a nature hike with her kids, she can be institute scrapbooking about their adventures and possibly sneaking a seize with teeth of chocolate. She writes about motherhood and family fun at Savour the Days.