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Difficulty Rating: ★★★☆☆
Difficulty Rating: ★★★☆☆
Parental supervision not required, but recommended.
Parental supervision not required, but recommended.
Background
Background
Have you ever wondered why you float in a pool of water while objects, such as rubber ducks, float? Take a guess. In STEM, guesses are essential!
Many people assume that this phenomenon is due to the difference in weight. However, we know this is false because of the existence of aquatic travel. Boats, yachts, and ships are all typically heavier than the average human. So, what is the reason? We can explain this by first visiting the common feature between objects, atoms. Atoms are the basic units of matter, composing the structures of everything in the universe except energy. Earth’s gravity pulls these atoms to the surface. The measure of this pull is called weight. When atoms bond with each other, they form molecules.
Image of two hydrogen atoms bonding with one oxygen atom, forming a water molecule
Recall the concept of matter. It’s all around you. The measure of the amount of matter in an object is called mass. I’m sure you’re familiar with the three main phases of matter: Liquids, Gasses, Solids. These are all variations of matter, with gasses having the loosest arrangement of matter and solids having the most clustered. The term eventually used to describe this scale is density. Density is how close molecules are in an object, or better said, the amount of mass that occupies a given volume (a measure of space). An item of high density is more likely to sink than one of low density. Similarly, one of low density is more likely to float than one of high density.
The best example of density action would be a balloon. The balloons most people are familiar with are helium-filled. Helium is an atom of extremely low density. For this reason, balloons float in the sky because the surrounding air is of a lower density. Over time, helium seeps out of the balloon, causing the balloon to sink. We know this based on our concept of mass and volume (Density = Mass/Volume).
“Recall the concept of matter. It’s all around you.” It truly is! Since we know that all you need is mass and volume, mass is a measure of matter, and that matter is in all things except energy, you can try this at home!
The Experiment
The Experiment
Now that you’ve learned a bit about density, it’s your turn to be the scientist!
What You’ll Need:
What You’ll Need:
A tall container: bucket, cup, bowl, etc.
Water
4-5 objects of your choosing (can fit in the container)
Pencil
Paper
Experimental Steps:
Experimental Steps:
Fill your container to the very top with water.
Examine your items and try to guess which will sink and which will float.
Write down your guesses on a piece of paper.
Slowly put each object in the container.
Record your observations (Sink or Float?).
Compare results to original predictions.
Repeat with any items of your choice!
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