Physics of hair gel: is it a solid or a liquid?

[Syntarsus]

My 9 year old came home from school today and told me they'd been taught hair gel is a solid not a liquid. This totally surprised me as I was pretty sure it was a liquid. Is there any way it can be considered a solid or is the teacher getting it wrong?

[garethmob]

Only have my phone but Wikipedia threw this up

http://en.m.wikipedia.org/wiki/Gel

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[Spackbackle]

Only have my phone but Wikipedia threw this up

Gel - Wikipedia, the free encyclopedia

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Just read the same thing, i guess its a liquid thats solid then??

[Paxo]

It can be regarded as both, it has a "solid" crosslinked structure and "liquid" in-between the solid structure. If the cross linking is extensive, it is more of a solid than a liquid.

Steve

[Dave Dubya]

I think it's known as "colloid" - a suspension of two states.

[garethmob]

Obviously I don't know for certain. But it might be a similar suitiation like in biology cells at gcse vs a level. Where one is a very simplified answer the other goes into so much detail to the point the neucleas has 4 lables

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[Syntarsus]

Ah, so it's both. Thanks for clearing that up.

[LeoLion]

It may be a thixotropic gel Thixotropy - Wikipedia, the free encyclopedia . More of a brylcreem guy myself ( 50 years ago)

Used to do lab work with low shear rate (air bearing) viscometers many moons ago .

Reading that wiki reminded me of what we called 'potty putty' - probably more correctly 'Silly Putty' - another material with interesting flow properties.

[Spackbackle]

Below is a copy and paste of liquid and solid definations. Seemsto fit into both!

Liquid:

One of four main states of matter, composed of molecules that can move about in a substance but are bound loosely together by intramolecular forces. Unlike a solid, a liquid has no fixed shape, but instead has a characteristic readiness to flow and therefore takes on the shape of any container. Because pressure transmitted at one point is passed on to other points, a liquid usually has a volume that remains constant or changes only slightly under pressure, unlike a gas.

1. Physics One of four main states of matter, in which the molecules vibrate about fixed positions and cannot migrate to other positions in the substance. Unlike a gas or liquid, a solid has a fixed shape, and unlike a gas, a solid has a fixed volume. In most solids (with exceptions such as glass), the molecules are arranged in crystal lattices of various sizes. 2. Mathematics A geometric figure that has three dimensions.

[DarkStar7]

Glass is a liquid. Honest check it out. don't sit and wait for it to flow though it may take quite a few centuries.

[ollypenrice]

Glass is a liquid. Honest check it out. don't sit and wait for it to flow though it may take quite a few centuries.

I always used to think this as well but a glass expert with whom I go cycling said otherwise. For a very detailed discussion of the issue sit down comfortably amd make your way through this lot!

Is glass liquid or solid?

The thick bottoms of church glass are certainly not due to long term flow, it seems. Disappointing! I liked the liquid flow explanation...

Olly

[Macavity]

I did think of Thixotropic... Also this video:

Silly Putty! - YouTube

Bummer, as they say?