Have you ever wondered if water can defy gravity and float in midair?
If you have, it may appear that way, but water cannot truly levitate.
However, with extra help, we can create an illusion that makes it seem like water defies gravity.
Our atmosphere is filled with invisible air molecules constantly moving and colliding with everything, including water.
These constant collisions create a force known as air pressure, which plays a crucial role in our experiment.
Under zero gravity, the air pressure exerted above and below a body of water remains identical. The equal and opposite forces tend to neutralize each other while the water remains stationary.
However, gravity then comes into play and pulls the water downwards.
We can observe an example of this physics principle at work with a fun water science experiment.
The “upside-down water trick” experiment illustrates how air pressure counteracts gravity, keeping the water in place even when you flip a glass upside down.
Adult supervision is advised so you can carry out the “upside-down water trick” experiment safely. This will create a captivating illusion where water appears to defy gravity.
It’s an engaging and magical experience that allows you to observe the fascinating interaction between water and air pressure.
Try out this fun water science experiment.
- clear plastic cup
- index card or thick piece of paper
- water bucket
- adult supervision
- Fill the cup to 3/4 full with water.
- Cover the cup with the index card. Make sure it completely covers the cup's month.
- Keep the card in place by pressing on it with one hand and move the cup to above the bucket with the other hand. The bucket can catch the water in case you don't succeed on your first try.
- Slowly turn the cup upside down while pressing firmly on the card to prevent water from leaking.
- Take a deep breath and remove your hand from the card. There you go, magical floating water!
As an Amazon Associate, I earn from qualifying purchases.
The Mechanism of the Floating Water Experiment
This experiment explores the properties of water and air pressure.
It is a hands-on activity using a clear plastic cup filled with water, an index card or a piece of paper, and a water bucket.
When you invert a cup filled with water without the index card, the water pours out immediately due to the force of gravity.
This, however, changes when you incorporate an index card into the procedure.
Covering the cup with the index card and securing it while flipping the cup upside down applies an upward force that counteracts the pull of gravity, maintaining the water and the card in position.
On removing your hand from the card, the card and the water remain suspended, seemingly defying gravity. This occurs due to the interaction of multiple forces.
Firstly, the water molecules are attracted to both the card and the cup, a property known as adhesion. This attraction between the molecules of water, the card, and the cup generates a minuscule force that unites the system, acting as glue.
Secondly, the water molecules exhibit mutual attraction, a phenomenon termed cohesion. These two properties, cohesion and adhesion, form an airtight seal around the cup. Under the influence of gravity, the volume occupied by the air inside the cup expands.
This expansion results in the same number of air molecules impacting a larger space resulting in lower air pressure inside the cup. The external air pressure becomes dominant, maintaining the card and the water in position.
However, if water leaks or air infiltrate the cup, even in a minute amount, the entire system gets disrupted.
The equilibrium of the water molecules is broken, and the external air rushes into the cup to equalize the internal pressure.
As a result, the water and the index card fall rapidly, ideally landing in the waiting bucket if you have executed the experimental procedure accurately.
This water trick experiment demonstrates a fascinating interplay of water properties, pounds of pressure, and the role of invisible forces in everyday life.
Not only does it present a hands-on exploration of scientific principles, but it also underscores the omnipresence of unseen forces that govern our world.
Want to explore more water trick experiments? Check out these science projects with water.
Here are more experiments making use of air pressure: