How does it work?

To produce sound in a tube you need two things - moving air and vibrations. The moving air is caused by Bernoulli's principle which states that slow moving fluids, like air, have a higher pressure (or force over an area) than fast moving fluids.

When you twirl the karruga horn around, the end in your hand stays relatively still while the other end flies through the air. Therefore, the fast moving end will have a lower pressure than the slow moving end in your hand. This means that the high pressure in the tube near your hand will push air through the tube to the moving end where the pressure is lower and can't keep the air in the tube. This provides the moving air needed to make the sound.

Still not sure? Try this:

You can change the pitch by changing the length of your karruga horn. For examples, watch these videos of

Now we know how the air moves through the horn but what causes the vibrations?

The key is in the ridges on the Karruga horn where the air moves through. The ridges must be on the inside of the horn! As the air moves through the horn and hits the ridges it begins to vibrate which causes the sounds we hear.

Watch the first video again. As the karruga horn is spun faster what happens to the pitch? As the air moves more quickly through the horn, it vibrates faster and the pitch increases.

On first inspection, many folks think the Karruga horn is merely the hose off a vacuum cleaner but think about what that would mean. Everytime you vaccuum your floor, the karruga horn would play its music, but the vaccuum cleaner pulls in a whole lot of air much faster than we can spinning it around our head. This means the pitch will be higher (faster air) and louder (more air). What do you think that would sound like? Watch this video to find out. We used a leaf blower instead of a vacuum cleaner but this just means the air moves in the opposite direction.

To be sure, take a look at the inside of your vacuum hose. Is it smooth or ridged?

Do It Yourself!

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