Fluids Experiment: Show Relationship Between Spigot Size and Fluid Velocity

(updated 21 November 2022)

You may have noticed that when you squirt water from a hose, you can make the water squirt faster and further by covering part of the end of the hose with your thumb. From this observation, you can guess that the smaller the size of the opening, the faster the velocity of the water or the greater the distance it squirts for a given pressure. This may get you curious as to how to verify the relationship between water velocity and size of opening or spigot size.

Finding the relationship between velocity and spigot size can be an idea for a science project in the area of physical science. You can do the experiment by seeing how far water squirts from different sized holes at a given depth in a container. You can then take data to establish the relationship.

This lesson will answer those questions.

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Purpose of experiment

The purpose of this experiment is to show the relationship between spigot size and the velocity of water. Velocity is determined by how far the water squirts. Data is taken to compare spigot hole size and velocity.

Research

Some of the research you can do is to see if others have done a similar project. This may give you ideas about how to perfect your experiment. You also need to know basic physical principles and laws.

Part of your study of fluids shows that the pressure is in all directions and is proportional to the depth of the fluid or liquid in an open container. Thus, the pressure on water in a container is the same for any opening at a given depth.

Experiment

You want to keep everything equal—such as the pressure—while you vary the opening size.

Materials

• Plastic milk or soda bottle.
• Knife or scissors
• Ruler

Steps

1. Cut several holes in side of the container at the same height. These holes should be different sizes. (This is not easy to do.)
2. Fill the container with water.
3. Measure the distance from the container that the water squirts out of each hole.

1Cut several holes in side of the container at the same height. These holes should be different sizes. (This is not easy to do.)

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2Fill the container with water.

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3Measure the distance from the container that the water squirts out of each hole.

Outcome

This experiment should verify that the smaller the area of the opening, the further the water squirts. If you were able to measure the diameter—and thus the area—of the holes, you could calculate the relationship between area and velocity for a given pressure.

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Be fluid in your actions

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Resources and references

Websites

Experiments Resources