Monday 3 November 2014

You Could Break A Glass Bottle Without Dropping It. But How?

What do you need?
To do this experiment, you will need a glass bottle, some string, a container of ice water and a pair of scissors. 

What to do?
First, cut a length of string and soak it in acetone (acetone is used as fuel). Then tie the string around the glass bottle. Using a lighter, burn the string. Keep turning the glass bottle that's on fire until the fire goes off. And then, quickly put the glass bottle into a pail of ice water.

What happens?
The glass bottle breaks into half after immersing it in ice water. This is because of an effect called 'thermal downshock'. Thermal downshock is the term given to cracking that results from rapid temperature change. This can also be observed when a hot glass is exposed to ice water — it will crack or break.

Watch the video above! In the experiment, a high temperature (hot) is created around the burned string and a rapid temperature change or shock occurs especially at that location when it is soaked in ice water (cold). The shock is the result of a drastic thermal gradient, which refers to the fact that temperature change causes expansion of the molecular structure of an object in different amounts.

This differential expansion can also be understood in terms of tension. At some point, this tension overcomes the strength of the material. As a result, a glass bottle will break into half!

Posted by Ayu

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