homemade submarine science project

Most kids know that that objects placed in water will either float or sink depending on the density of the object. This science project will remind us that the density of our spiritual life can keep us from sinking into loss of our faith in Christ.


– Empty plastic water bottle
– Baking powder
– Scissors (to make holes in the bottle)
– Five Marbles
– Large tub (or an empty fish aquarium will work.


We have spent much of the school year running around and doing important stuff – studying, learning, improving, striving. We’ve been very “up” in our energy. God rested when He was finished His creation. We can have our “downtime” during the lazy days of summer. We’re a little like this bottle. We need to come back down, just like the bottle will, and come back up again when it’s time to start school. Let’s watch and see”¦


1. Fill your tub with water.

2. Use the tip of the scissors to make four holes along one side of the water bottle. This will be the bottom of the submarine.

3. Pour a tablespoon of baking powder into the bottle so that it settles over the holes.

4. Add five marbles to the bottle. This will help add weight to the bottle and keep it from rolling over the top of the bottle.

5. Put the cap on and tighten it.

6. Place the bottle bottom-side down into a tub filled with water. The water will fill the bottle through the holes in the bottom, causing it to sink. When the baking powder reacts with the water inside the bottle, it will release carbon dioxide gas. This will create bubbles and cause the bottle to rise back to the surface of the water. This can be repeated several times before the baking powder is completely dissolved.


When something placed in water is heavier than the weight of the water it will sink. The bottle is not heavier than the water. However, the holes enable it to fill with water, and then the weight of the inside of the bottle becomes equal to or greater than the weight outside – it sinks!

The baking soda creates carbon dioxide gas when it mixes with water, which in turn creates air bubbles. Air is lighter than water. Once filled with enough air, the bottle will move toward the surface again.


We’re a little like this bottle. We’d love to be floating around doing things all the time. But we need time to rest. We need time to simply be, and let God fill us with good things so we won’t get burned out. The baking powder is like God’s power. It keeps us afloat while His spirit fills us – and we’re no longer just filled with hot air!



You might also be interested in these other awesome science project ideas & activities!

walking water bible science experimentvapor-to-rain science experimentfireworks in a glass science experiment

Looking for more great Bible science project ideas?  Then be sure to check out our Bible Science area!  And don’t forget to Become a Fan on Facebook, Follow Us on Twitter and Come Hangout with Us on Google+!


Linking up at: A Mama’s Story, What Joy Is Mine, Nourishing Joy, savvysouthernstyle.net, wholeheartedhome.com, flusterbuster.com, thelifeofjenniferdawn.com, thenewlywedpilgrimage.com, w2wministries.org, theturquoisehome.com, jannolson.blogspot.com, serenitynowblog.com, shabbynest.blogspot.com, simplelifemom.com, chiconashoestringdecorating.blogspot.com, Simple Saturdays Blog Hop, madefrompinterest.net, flamingotoes.com, The Sunday Showcase, lifeonlakeshoredrive.com, Create With Joy, A Blossoming Life, A Pinch of Joy, Uncommon Designs, homestoriesatoz.com, Coastal Charm, The Scoop, A Stroll Through Life, Between Naps on the Porch, Fine Craft Guild, The Twinkle Diaries