# Fast and Easy Science Fair Projects: Water Shooter

Updated on December 30, 2019
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## Compressing a fluid

Overview: Hydraulics, from the Greek word meaning "about water." is the study of liquid in motion. A part of hydraulics deals with compressing a liquid, used in machines where great pushing of lifting strength is needed. A force pushing on any part of an enclosed liquid creates and equal pressure per unit of area on everything the liquid touches. By using a system of pistons (cylindrical containers filled with a liquid), great force can be achieved.

Hypothesis: When water is compressed and forced to flow out if an opening, the velocity of the water will be much greater if the opening is small than if it is large.

You need:

• Squeeze bottle with spout top
• A piece of heavy board
• Water
• Ruler

Procedure: Outside, remove the spout and fill the squeeze bottle with water. Set the board on its side and tilt the container against it. Let water leak out until it stops; the angle will keep most of the water inside. Then with your hand, strike the side of the bottle, forcing water out through the opening. Watch how far the stream of water shoots.

Again, fill the squeeze bottle with water, set it against the board and let the water leak out. This time, screw on the spout. Keeping the volume of water Constant (by tilting) as well as the striking force used on the bottle, our Variable will be the diameter of the opening through which the water escapes. The spout makes the opening much smaller. Strike the side of the container again, using the same amount of force as before. Does the stream of water travel farther with the spout on? Does that mean the velocity of the water coming out was greater?

Results and Conclusion: Write down the results of your experiment. Come to a conclusion as to whether or not your hypothesis was correct.

Something more: Compare the amount of water coming out of the bottle with the spout off and with it on. Use a measuring cup to quantify  the volume of water in the bottle before and after each strike. Perhaps, with the spout on, less water is coming out? Did you strike the bottle with the same force each time? Can you find a way to be sure?

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