Kids will love learning about how water pressure changes with depth in this Water Pressure With Water Bottle Experiment. This can even be used to explain the force that water pressure has on deep-sea divers and scuba divers too!
Get more fun and easy Weather Experiments for Kids here!
The best thing about this cool experiment is how simple and easy it is to do with household items you already have!
Water Pressure With Water Bottle Experiment
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How to Discover the Science of Water Pressure
- Poke a few holes at different heights on a bottle or cup.
- Pour water into the bottle (Add food coloring if desired).
- Pay attention to which holes in the bottle spray water out with the most force.
Step 1: Poke 3 Holes In a Bottle
I like to use a large 2-liter bottle for this experiment, but even a smaller water bottle will work too. Make sure the label is removed from the bottle and it is nice and clean before creating the holes in your bottle.
Then using a sharp nail or screw, and with adult supervision, carefully poke 3 holes at different levels on the bottle.
I usually poke one hole about an inch from the bottom of the bottle, another in the middle, and the last hole a little bit closer to the top of the bottle.
Step 2: Fill The Bottle With Water
Adding food coloring to the water will add to the visual display of your experiment, but you may want to skip this option if you are worried about your little ones making a mess with it.
If you do add some food coloring to the water, it’s easiest and the least messy to mix it into a bowl of water before pouring it into the bottle.
Use a funnel and pour enough water into your bottle to fill it all the way to the top. It might be helpful to have someone else plug the holes on the bottle with their fingers to keep the water from leaking out while filling it up.
Also, don’t forget to put a large pan underneath the bottle to prevent water from spilling and spraying everywhere!
You will also want to put a large bowl upside down in the pan and use it as a platform to set your bottle up a little higher (you will see why this is important in the next step).
Step 3: Watch The Water Spray Out of The Holes at Different Levels
Now it’s time to release the water from the bottle and watch what happens! Which hole do you think the water will shoot the farthest out of!!?
You may want to have some extra water to keep pouring into the top of the bottle to keep the water level high enough to flow out of all three holes.
If you guessed that the hole closest to the bottom of the bottle would shoot water the farthest, you were right!
Now it’s time to find out what makes the water shoot so far out on the bottom hole and not very far out of the top hole!
Water Pressure Experiment Explanation
As we saw in this experiment, the hole that has the most water above it, shot water out the farthest and with the most force! This is because as the water depth increases, the water pressure increases!
Water pressure is created from the weight of the water pushing down on an object or a surface. Water is very heavy and dense, so the deeper underwater you go, the more weight, or pressure you will feel.
Another type of pressure is air pressure. Believe it or not, the gases that make up the air around us actually do weigh something! To learn more about air pressure, check out this Water Bottle With Holes Experiment.
Our Earth is covered with a layer of air that is about 80 miles thick called the atmosphere. The entire atmosphere which is a whopping 80 miles thick has the same pressure as being below only about 30 feet of water.
Because water is much more dense than water it makes sense that it only takes a water column 30 feet deep to create the same pressure as 80 miles of air on top of you right!?
This is why scuba divers have to train and prepare carefully before diving deep into the depths of the ocean!
If they don’t train properly and use the right equipment, the extreme water pressure can cause them to have major health issues.