Friday, May 11, 2012

Non-Newtonian Tomatoes

Last day of Science Week!  To finish off a fabulous week we are planning to have Fush and Chups covered in tomato sauce.

Tomato sauce is actually pretty special.  It’s a known as a non-Newtonian fluid.  This means it acts differently to forces that everything else.  They are called non-Newtonian as Newton did so much pioneering work around forces.

They are a bit tricky to explain.  However, the explanation is much easier after you spend some time playing with non-Newtonian fluids. 

Luckily it’s super simple to make!

Just mix some corn flour with water.  You’ll end up with a thick material. 

This amazing material acts like liquid when you pour it.  But it acts like a solid when you hit it with a sudden force.

Some interesting stuff to help you explore more …

Put your finger in it and move it around slowly – what happens when you move around the material faster?
Get a bowl of water.  Hit the water with a spoon.  Then try hitting the non-Newtonian fluid in the same way.  Talk about the difference.

If we look at our corn flour and water mixture under a microscope the corn flour particles would look like rough formed hexagons.  In between those particles would be the water and starch ones – acting as a lubricant.  Most of the time all these particles slide past each other.  They are acting like a liquid.  However, when a sudden force is applied the sides of the particles rub together and the friction holds them together. They lock together like crazy paving. As soon as the pressure is off, everything starts moving freely again. 

Non-Newton fluids are all around us.  Tomato sauce is just one example. Scientists still don’t fully understand Non-Newtonian fluids.  They are still trying to unlock the secrets behind these fascinating materials.  Once they do, it will open up a whole range of new materials and inventions.  

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