Cracked marbles are manufactured out of glass, which is cracked through a process known as thermal shock. The glass is first heated, forcing it to expand unevenly, and then cooled rapidly, forcing it to shrink unevenly. The resulting stress on the glass causes it to crack. Cracked marbles therefore serve as an excellent classroom experiment, but also have a crafty, decorative appeal since the resulting cracked surfaces sparkle and glimmer like gemstones.
Things You'll Need
- Safety goggles
- Old skillet or disposable aluminum pan
- Pot holders
- Slotted ladle
- Soft cloth
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Fill a bucket with two parts water and one part ice.
Put on your safety goggles.
Pour your marbles in a single layer into an old skillet or disposable aluminum pan.
Heat the marbles on your stovetop, between low and medium heat, for approximately 10 to 15 minutes; or preheat your oven to 350 degrees and heat the marbles for 10 minutes.
Turn off the oven or stovetop and remove the skillet or pan from the heat source with a potholder. Pour the marbles into your bucket of ice water.
Wait for the ice to melt. When melted completely, scoop the cracked marbles from the bucket with your slotted ladle and lay the marbles on a soft cloth to dry.