Simple Science: Dilatant Materials – Silly Putty and Melting Martians

The boys received Melting Martians for Christmas…

It is a surprisingly simple idea but it has kept the boys entertained for a lot longer than I would have expected. It’s also neater and cleaner than Play Doh – I wonder if we can get more of this stuff from somewhere…?

Here’s how it works:

You build a Martian with the putty and plastic parts.

The boys have let their imaginations run wild with their creations…

Then leave it for a few minutes and the Martian will “melt” as the putty loses its shape.

It’s a neat way to teach the kids about the cool and unique properties of Silly Putty, which is a dilatant (also referred to as shear thickening) material:

• you can stretch it without tearing it, although you can break off bits of it easily
• if you throw it against the floor, it will bounce
• it will keep its shape when you hit with a hammer, but you can squish it in your palm to change its shape

Did I also mention how much fun they have with it?

Make Your Own Silly Putty

Here’s a recipe from YMC (Yummy Mummy Club):

1. Mix 250 ml of hot water with 7 ml of borax powder until all the borax dissolves. Set this solution aside.
2. Get a cup and mix 30 ml of Elmers Multi-purpose Glue with 20 ml of water.
3. Add two or three drops of food colouring to the glue/water mixture.
4. Once the glue, water, and colouring is mixed together well, add 20 ml of borax solution. Stir this all together.
5. Take the mix out of the cup and knead it. Be sure to pop all of the bubbles of glue. More borax solution can be added if it is very gluey. Knead it until it has a consistent texture. You now have silly putty!

You can also try this recipe from PBS:

1. Mix Elmers Multi-purpose Glue with the food coloring until the color is even throughout.
2. Pour Sta-Flo concentrated liquid starch into the colored glue mixture.
3. Stir and let it sit for five minutes.
4. Pull the putty out of the mixing bowl and set it on a paper towel. Knead the putty in your hands for five to ten minutes.

Related:

• Resources for Science Experiments