How to Make Cracked Glass Marbles for Crafting
When glass is heated, it expands. On the other hand it contracts when cooled. So when you take a heated marble and dump it in into ice cold water, the outside shrinks up so fast that it causes the inside of the marble to crack. ... but a simple plastic container works just as well. Step 3: Drop Marbles Into Ice Bath. When the 20 minutes …
