Homeschool Space Unit Study | Solar System Science Experiment: Earth

I designed this science experiment to emphasize one of Earth's most unique characteristics as part of our homeschool Space Unit Study! If you're learning about space or the solar system, this science activity is perfect!

Homeschool Space Unit Study

Start out by asking your kids what makes Earth unique among planets in our solar system. Here are a few fun facts:

* Earth travels around the sun at 67,000 miles per hour!
* Earth "bulges" around the's not a perfect sphere!
* Earth's crust is constantly recycled through the rock cycle.
* Earth sometimes has a "temporary" moon when its gravity captures small, nearby asteroids that are flying through the area. They are usually 1-3 feet wide and orbit the Earth for a couple months (usually about 3 orbits) before flying away from Earth!
* 70% of Earth is covered by oceans.

This enormous amount of water helps control the Earth's temperature and climate, which allow life to exist in the most biodiverse form of any planet in our solar system!

So, today's experiment is all about water, and one of water's really unique characteristics: surface tension.

There are a lot of different experiments that will demonstrate surface tension. Here is one that we altered to make a Christmas tie-in.

This surface tension experiment is super easy, sets up in seconds, and is so very visually stunning that all ages enjoy it!

To prepare for the experiment, grab a cup or bowl, fill it half full of water, and have your kids grab a container of glitter and some liquid dish soap.

Earth Science Experiment:
Surface Tension!

 Explain to your kids that a molecule of water looks like a "Mickey Mouse Head." The "ears" have a slightly positive charge and the "mouth" has a slightly negative charge. 

If your kids are older or have a good grasp of atomic structure, you could explain a water molecule is made of one oxygen and two hydrogen molecules that share electrons in a covalent bond. It takes longer for the electrons to travel around the oxygen, so the oxygen has a slight negative charge. Since the electrons are spending more time going around the oxygen, that leaves more protons at the hydrogen end of the molecule, giving it a slightly positive charge.

Anyway, explain that the positive and negative ends of the molecules of water attract each other, forming "hydrogen" bonds. These bonds are easily formed and broken as the charges on individual water molecules fluctuate, but the end result is that water tends to "stick" to itself.

A container of water, like your bowl or cup, has a surface that is "sticky" because the water molecules positive and negative ends are attracted to each other. We call this "surface tension."

Surface tension creates homes for many animals. We're going to take a look at it with this experiment:

1- Sprinkle a little glitter across the top of the water.

It will float around on the waves of water in your bowl.

2- Squirt a tiny puddle of dish soap on the table and have one of your kids dip a finger in it. Then dip that finger in the middle of the bowl.

That's it! The glitter will dramatically move away from the soap!

You might have to repeat it a few times because it's so cool! If you do, be sure to rinse out your bowl each time.

What's going on?

Dish soap breaks the surface tension by interrupting the positive-negative interactions between water molecules. It interrupts right where your finger touches the water, creating a wave that forces any remaining surface water molecules still bound to each other to race away from where you touched. The glitter sitting on top of the water is also carried away with the water. The glitter actually shows you where the water molecules are traveling!

This is why we use soap when interrupts the chemical bonds between dirt or germs and our skin! Then water rinses the dirt down the drain.

Keep Experimenting!

Do any other liquids make water/glitter behave the same way? Can you find the most effective soap in your home? Do any other little solids behave like the glitter?

Record your results in a science notebook! Include a diagram showing the positive and negative sides of water molecules, and how they're attracted to each other! 

Do you have preschoolers in your home? I have a preschool-level version of this same experiment here! I've found that when I have mixed ages the best solution is to give the preschool-aged explanation first, then follow with more details for the older kids. The preschoolers will either ignore what they're not ready for or go play...or pick up more science than you expected!  

Are you looking for a space or solar system themed homeschool science curriculum? I'm putting together one for elementary aged students right now! You can get the experiments and other activities as I publish them by visiting the Homeschool Space Unit Study page here!

And if you're looking for more homeschool unit studies, be sure to check out our growing collection here!

Happy Educating,
Carla & the kids who don't sit still!