Easy way to cut a glass bottle
A perfect way to turn a bottle into a pencil holder
Perform this experiment only under adult supervision.
- glass bottle;
- cotton string;
- isopropyl alcohol;
- deep container with cold water;
Wind a cotton string around a glass bottle. Soak it with isopropyl alcohol and set it on fire. Rotate the bottle so the glass heats evenly. Then immerse the bottle in cold water – it will crack where it was heated. Sand the edges with wet sandpaper. Your glass is ready!
The isopropyl alcohol burns on the cotton string, releasing plenty of heat. The bottle must be kept horizontal and rotated constantly so that it heats evenly. Glass has poor thermal conductivity and mainly warms up exactly where it’s heated. As the glass cools abruptly, a temperature difference arises between the outer and inner layers, and the effect of thermal expansion creates tension inside the glass, cracking it.
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