Cutting a bottle with the use of a string is an easy Physics magic but you can surely amaze your audience with this. On the other hand, it’s a magic you need to prepare for because of different needed materials. This is not a magic that you could hide in your sleeves but rather a prepared one to show how Science can produce magic to human’s eyes. But beware to take precautions such as wearing goggles to protect your eyes.

- a bottle

- string/yarn

- Acetone

- lighter

- cold water

- pot holder

1. First and foremost, prepare the needed materials especially the cold water.

2. Get a string/yarn and encircle it to the bottle’s neck twice.

3. Tie a knot so you could remove it and bring it back easily again.

4. Remove the fixed yarn/string and dip it to the Acetone.

Note: Remember to first try if you could return it easily to the original place on the bottle.

5. Return the yarn dipped into the Acetone to the bottle’s neck.

6. Light the yarn by continuously using the lighter. The hotter the bottle, the better.

7. Quickly place the bottle into the cold water.

8. In just a matter of second, see how the bottle will be cut to the place where the yarn was placed.

So what’s the Physics principle behind it?

Thermal Shock! It’s the cracking result from the rapid temperature change. At first, the bottle was heated. And it was placed into a cold water producing thermal shock.