BBOS – Gravity Goo and Garbled Marbles

This BBOS experiment was supposed to be in two parts – first mixing some crystals into a giant test tube of water, then pouring it back and forth till the crystals dissolve and form a giant polymer (i.e. transparent goo).

It’s called “gravity goo” because it’s supposed to self-siphon against gravity and flow uphill from one cup to another (as the instruction booklet mentions).

But I realised it doesn’t really do that, and after two youtube videos showed that the polymer behaved the same way ours did, I figured what it might really mean is that it moves simply by the force of gravity, the way a slinky does.

The set-up

We “grew” the garbled marbles as usual, over an hour, waiting for the mustard seed sized hard marbles to expand into bouncy clearish spheres.

She was really quite happy, whatever that smile conveys. :S

B helping with putting the expanded garbled marbles into the gravity goo

K had a lot of fun pouring and observing

Unlike water, the goo keeps flowing even if you hold the upper test tube stationary. Dragged down by the force of gravity and the weight of the goo that has already flowed down, the colourful balls cascade down merrily, which is quite a pretty sight.

See how the balls flow slowly as they adhere to the goo

The last part comprises pouring out all the goo onto newspaper, and that usually is the part they enjoy the most, squishing all the balls and goo and creating a great big mess! ^_^

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