Recycling - How to cut a glass jar with just oil, water and a blade

Here's an interesting experiment you can try at home.  The video at the end of this post shows you how to cut a glass jar with just water, oil and a blade.

If you’ve got kids, then this may be a fun one to try with them - It’s a great way to make science a bit more interesting, whilst creating something that that they go on to use afterwards as well.

It will also teach them about the benefits of recycling old things that are going to be thrown away, into new things that they can use.

If you're thinking of trying this experiment for yourself, take a look below for more detailed instructions.


For this experiment you’ll need:

  1. A glass jar
  2. A large bottle of water
  3. A handheld blowtorch
  4. A metal bowl
  5. Cooking oil
  6. An old metal blade
  7. Sandpaper

First, go and find a suitably sized glass container such as a jam jar. Fill the jar with water up to a level where you want the jar to be cut. Then place the jar in a metal bowl similar to the one used in the video. Pour cold water into the bowl to around the same level as the water in the jar.

You’ll then need to go and find some oil (cooking oil should do the trick). Take a capful of the oil and pour it onto the water. According to the video, you'll need to do this around 20 times so that there is a film of oil covering the entire surface of the water. You’ll see that the oil will float on top of the water which is exactly what we want it to do.

Hopefully, you’ll have something like an old saw blade lying around at the bottom of a toolbox. If you don’t have this, then something similar will do.

Heat the blade with the blowtorch until it glows red hot. Make sure you’re not holding the other end of the blade with your fingers - use a pair of pliers to grip it instead.

Dip the blade in the layer of oil for a few seconds - you’ll need to hold the blade at a shallow angle to do this as we only want to heat the oil, and not the water underneath it.

You’ll then find that the jar is (hopefully!) cut. Make sure to smooth off the new rim of the jar with the sandpaper to ensure there are no sharp edges to cut your fingers on.

Apparently, the science behind it is that the glass cracks at the level of the oil because of the sudden difference in temperature between the oil and the water underneath it.


At Expert Skip Hire in Sussex, we always love stories involving recycling and waste management, and this fun scientific experiment ticks all the right boxes!

If you try this, stay safe and good luck with the experiment...

About Expert Skip Hire, Sussex

We're a family run, well established skip hire company in Sussex. We take a keen interest in what's going on in the world of waste management and are always looking to provide our customers with the latest innovative ideas and amusing stories relating to skip hire and waste management/ recycling in general.

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