How to Whistle an Acorn Cap

Let me warn you from the start that acorn whistles are ear-splitters. - SciencetoyMaker

Before you start:

You only use the cap of the acorn to whistle with--not the whole acorn. You will have to remove a cap from the rest of an acorn. Although acorn whistling is simple once you have done it, you will have to experiment at it a bit to learn it. Larger caps are easier to learn on, while smaller ones seem to be slightly louder.

Step1: Divide the acorn cap.

I don't mean chop it up, but mentally divide the acorn cap into 3 sections. The top section is what you will see when holding the acorn. Notice that it is smaller than the bottom sections because we divide from a point above the center of the acorn.

Step2: Form a "Y" shape with your thumbs.

You will have to rotate your thumbs to get it. By holding your thumbs that way, you will hide the bottom 2 sections, but see the top, triangular section.

Step3: Hold the acorn.

Hold it between both thumbs and both pointer (index) fingers, as shown in the illustration. Make the "Y" shape with your thumbs and position them to show only the small, top, triangular section of the acorn.

Step4: Make it whistle.

Constrict your lips a little and blow hard--just as if you were blowing out a candle that was 3 feet away from you. The knuckles of your thumbs will rest right in between your lips. The thumb knuckles won't get past your lips into your mouth, though, because your lips are pursed.
When you get it, you'll know it. You might have to play around a little with the following variables:

  • Rotate your wrists forward and backward to change the angle of the acorn slightly. You are seeking a balance between part of the air stream curling around in the acorn cap while the rest of the air rushes over the top edge.
  • Vary the size of the triangle of acorn visible between your thumbs. Smaller usually works best for me, but experiment.

I'd like to know how this project goes for you. I'm happy to answer questions about it. Feedback from you is an important way for me to know what works and what needs clarification.