Crafting "fake potions" Still working on my costume

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I would like to know a method for crafting fake potion bottles for shows, i want the bottles to be:


Approximately the size of an apple
Resist the pressure of being transported in bags
Resist weaker impacts
Don't leak any liquid
Not considerably heavy




Aditional info:


It doesn't need to be made of real glass
It doesn't need to contain real liquid
I don't pretend to craft the "bottle" itself, but I want to know what may be used to represent it (A light bulb, a medicine bottle, etc...)




Visual representation:



PS.: I'm not sure how to tag it so feel free to edit it
For a few reasons, I'd go with holiday ornaments. These are available in clear plastic, rather than glass, which is less of a breakage worry. They're also cheaper and lighter than glass jars. And they're already nicely spherical!


an example from Michaels craft store


Ditch the metal collar and ring.
Fill with a colored epoxy resin.
Add a decorative cork.


The main advantage of this is that it wouldn't spill. Also, if it does crack from being dropped or struck, the epoxy would hold the pieces together, reducing the chance of injury or mess.

But if you want the internal liquid to slosh about and look very potion-like, that's also feasible:


Ditch the metal collar and ring.
Fill with colored liquid.
Add a decorative cork, and glue securely in place.


That shouldn't spill either, assuming it's well-glued.