by Michelle Crooker

This post is part two of my seven-part, days-of-creation science series. If you missed the first part you can go back and read Creation Science Day 1 – Let There Be Light.


Day 2: Separating the Waters

“Then God said, ‘Let there be an expanse in the midst of the waters, and let it separate the waters from the waters’” (Genesis 1:6 NASB).

Not being a theologian, I am not going to tell you that I know for sure what this means; however, I will tell you my thoughts. When I read this verse I think of the sky and the atmosphere, so I decided to have a chat with the kids—first about water and the water cycle, then about the atmosphere and pressures.

Have your students answer this question: Why do we need water?

Their answers will probably vary—from needing water to drink, to water plants, to cool things off—and that’s fine. The basic idea is to get the kids thinking about water. Explain to them that while most of the Earth’s surface—around 70 percent or so—is covered by water, only about 3 percent of that water is fresh water. If that is the case, then how is it that we still have any drinkable water left on Earth? We’ll conduct our first experiment to answer this question.


Experiment #1 – Water Cycle

  • Materials

    • Heat-resistant, clear container

    • Very hot water (adult assistance required)

    • Bowl that will fit on top of the heat-resistant container

    • Ice

  • Instructions:

    • Explain to the kids that you are going to create your very own water cycle.

    • Pour the hot water into the heat-resistant container.

    • Place the bowl on top of the container and place the ice into the bowl.

    • Allow it to sit for a little bit until you see condensation beginning to form on the inside of the container and the underside of the bowl.


How It Works

The ice in the bowl causes the moisture in the warm air, created by the hot water inside the container, to condense and form water droplets. Because the bowl seals the top of the container, the water droplets cannot escape, so they will form on the sides of the container and the underside of the bowl.

This is the same thing that happens in the atmosphere. When warm air rises, it meets colder air in the atmosphere. The water vapor then condenses and forms precipitation that falls to the ground, and the process is repeated. It’s pretty cool how God made it so that the 3 percent of fresh water on Earth is continually being renewed.

Water cycle

Here is a simple version of the water cycle. You can print out a copy here (88) (with labels) or here (64) (without labels). After we finished our talk about the water cycle, we moved on to the atmosphere.

Most people know that without the atmosphere there would be no life on Earth. The atmosphere contains the air we breathe, protects us from harmful UV rays, and keeps the Earth’s climate moderately stable. Atmosphere as a unit of measure refers to pressure. At sea level, one atmosphere is equal to 14.7 lbs/in2. In space there is very little density, making it an almost-perfect vacuum. This leads us to our next experiment:


Experiment #2 – Creating a Vacuum

  • Materials:

    • Long-necked bottle or other container that can be vacuum sealed

    • Vacuum pump (I found mine at Wal-mart)

    • Marshmallows that can fit through the opening of your bottle

  • Instructions:

    • Fill the container about half full of marshmallows.

    • Ask the kids what they think will happen to the marshmallows once they are in a vacuum. After explaining to my class that being in a vacuum means there is no pressure, and that it does not mean the same as being weightless, they all decided that the marshmallows would squish together.

    • Using the vacuum pump, remove as much air as possible. So that the marshmallows do not expand and wedge themselves into the container, you may want to remove a bit of air, shake the container, remove some more air, and so on.

    • After you have removed all of the air that you can, you will be able to show the kids how the lack of pressure doesn’t squish the marshmallows, but in fact allows them to expand.

    • Finally, be sure everyone is watching closely and let the air back into the container. When you do, the pressure equalizes and the marshmallows quickly return to their original size.

image03 2014-03-06-11.33.38 image04

Marshmallows before vacuum

Marshmallows in a vacuum

Marshmallows after vacuum

Next, we went on to discuss the opposite of a vacuum—too much pressure.

Ask the kids to think of places where there is too much pressure. If they have ever gone swimming, remind them to think about how their ears felt as they went further under the water. Discuss how the pressure increases the further underwater you go and how there are places in the ocean where we cannot go because we do not have anything that can stand the pressure.


Experiment #3 – Too Much Pressure

  • Materials:

    • 35 mm film canister w/lid

    • Alka-Seltzer® tablets

    • Water

  • Instructions:

    • Place one Alka-Seltzer® tablet into the film canister.

    • Add water, and then—making sure the canister is not pointed towards any people, animals, or anything fragile—quickly attach the lid to the canister.

    • Wait and see what happens!

The gas released when the Alka-Seltzer® becomes wet creates pressure inside the canister. As there is nowhere for this pressure to go, the cap will eventually pop off!image05

From here, you can go on to discuss what happens when pressure builds up under the earth, which opens the way for you to teach about volcanoes and earthquakes. For a grand finale experiment you can always grab a Diet Coke® and some Mentos® and head outside to create a volcano!

Be sure to tune in next time; on day three, dry land and seeds appear!

Michelle, a Virginia native, currently lives in Pennsylvania with her husband and three children. Active in Scouts, area homeschool groups, and with her family, she can be found on her blog, “Homeschooler on the Edge,” as well as Facebook, Twitter, and Pinterest.