Cool science experiments don’t just exist in classrooms or laboratories. With a little creativity and a few regular party items, you can perform this science experiment for kids that will show kids the basic principles of liquid density and water displacement.
Party Stuff You Will Need:
- 1 Coke can (unopened)
- 1 Diet Coke can (unopened)
- 1 six liter glass beaker or jar full of water (a small water cooler filled with water can also achieve the desired effect if the kids can view the demonstration from above.)
A Simple Magic Trick – and a Cool Science Experiment
Get the kids to surround the glass beaker, jar, or water cooler.
Show the kids the Coke can and Diet Coke can – pass them around and let them touch them to see that there is nothing different or unusual about them. Allow the kids to confirm that the cans are unopened and of the same size and shape.
Now ask the kids, “Since the Coke can and the Diet Coke can are the same size, do you think they will sink in the water or float?” Let the kids come up with their own guesses and hypotheses before dropping the Coke can and Diet Coke can in the water one by one.
Kids will be surprised to see the Coke can sink to the bottom of the water while the Diet Coke can will float and actually break the surface of the water.
Why did this happen? Allow the kids to come up with their own ideas before letting them in on the reason behind this phenomenon.
Facts about Liquid Density and Water Displacement
This magic trick works based on the principles of liquid density and water displacement. Density is the relationship of an object’s mass to its volume, or how close an object’s mass is packed together. Objects with high density (like a rock) have their mass tightly packed in a small volume. Objects with low density (like sponges) have their mass spread across a wider volume. Because dense objects have more mass relative to their volume, they are heavier than a less dense object of the same size.
Water displacement is what happens when an object pushes aside a certain amount of liquid when it enters a liquid (like the water that rises or gets splashed out of a pool when you dive in). If an object displaces more than its weight in liquid, it floats. But if an object displaces less than its weight in liquid, it sinks.
Because of this, objects that are denser than water will sink while objects that are less dense than water will float.
Coke is a soda made of ingredients denser than water (such as sugar). However, Diet Coke ingredients (such as its artificial sweeteners) are less dense than water. Because of this, the denser Coke sinks in water while the less dense Diet Coke floats.
Source:
Klonowski, Stan. Ocean Adventures, Tempe: Changing Hands Bookstore, 2009.
Want to try out more cool science experiments that let kids experience the principles of density first-hand? Then check out Science Experiment Teaches Kids About Density and Fun Party Trick Also a Cool Science Experiment.
And find more resources that provide science experiments for kids at Author Conrad Storad Excites Kids About Science.
