It is proven repeatedly that with super easy science experiments, you do not need to re-invent the wheel to have fun! In any way, tying knots in bones are far more fun and impressive than trying to re-invent the wheel!
In order to tie knots in bones, we need to understand the basics first by doing a simple experiment with an egg. You can use a raw egg, but it is less risky with regard to cleaning if you use a boiled egg.
Use a clear glass or jar and fill it up with enough vinegar to cover the egg completely and place the egg into the glass or jar filled with the vinegar. You will see the principal of the experiment starting to happen. Do you see the bubbles rising from the egg? Good, now leave the egg in the vinegar for at least 24 hours.
After the 24 hours have expired, take the egg out of the vinegar. What happened? The eggshell has become completely soft! Now repeat the same experiment, using the same vinegar, and put some chicken bones in the vinegar and wait 24 hours again.
Once you take out the egg of the vinegar, place it on a plate or in a bowl and leave it on the table for another 24 hours. At the end of the 24 hours, take the bone out of the vinegar and make a knot in it! Place it on a plate as well. What happened to the egg that you left on the table after the 24 hours? It became hard again!
Here is how it all works. The eggshell, just like the bone, contains calcium carbonate and that is the substance that makes the eggshell and the bone hard. Vinegar is an acid substance and once you combine or bring these two substances into contact carbon dioxide is released. That was the bubbles you were seeing. This chemical reaction will continue until all the carbon in the shell of the egg or in the bone is completely used up. This process takes about 24 hours to complete.
So how do the egg and the bone becomes hard again? The calcium that remained in the bone and eggshell absorbed the carbon dioxide in the air and this caused the bone and the shell to become hard again!
With the chicken bones hard again, show them off and see if people can clarify the mystery of the knotted bones!