Well, for a small-scale experiment, it’s easy enough to whip up a small batch of cornstarch and water.

I wonder how the cement mixer managed to churn the stuff, though. Unless it was turning really slowly, of course.

That would be one of the best Christmas gifts for me, able to do that all day and night, any day.

You can do the same with a small kiddie pool and lots of custard, but don’t let your feet get sucked in it will take like three guys to pull you out.

What is that stuff, that’s the coolest thing I have ever seen!!!!

Corn starch you say? - LOL! - when you said cement-mixer,I thought it was cement at first! - (pretty damn sloppy,white cement,i’ll grant ya!)

I don’t know if that’s what they used, but it had the right color for a cornstarch and water mix.

You can easily try this at home. Dump some cornstarch into a bowl and slowly work in water with your hands. You’re looking for a saturation point and it’ll be obvious when you’ve hit it. If you move your hands slowly in the mixture, it’ll behave like a liquid. Move fast and it’ll stiffen way up.

See this and that.

You may find this interesting when it comes to walking on liquids:

Surface tension is caused by interactions between components of a mixture, it takes energy to disrupt these interactions and so if you penetrate the surface you are decreasing the number of interactions, requiring energy, therefore some things that may be more dense than a liquid can be forced to float (i.e. a pin on water). All liquids have some degree of surface tension, it just varies with the enthalpy of interaction. To penetrate the surface you must give energy to the volume you want to disrupt, note Joules per cubicMeter = units of pressure, and this can be converted into Force per unit area by using the equation for work Joules=Force*Meters to substitute in(which expresses force exerted over a distance in terms of energy- the deeper you penetrate the liquid with a needle the more energy is needed- if the needle isn’t completely submerged).

With the force per unit area units you can see that the more spread out your force the more energy would be required to penertate and there will be critical pressure of penetration. Interestingly the meniscus of a liquid can dome upwards to maximise interactions with itself - i.e. mercury in a glass container, or downwards to maximise interaction with the container - i.e. water in glass container, depending on what is more favourable to interact with. You can change surface tension by what you add, and if you add washing up liquid to a pond the waterskaters will sink, I suppose when parachutists say landing in water is a hard landing, if they squeezed bottles of washing up liquid into the water near impact they would make their penetration easier and soften the landing.

In the videoclip we say the liquid with high surface tension, however they do penetrate if sthey stay there long enough so they are above the pentration pressure of that mixture, there is a second property, viscosity, that is how quickly a liquid/mixture can move, and by running across it they were taking advantage of it. Viscosity increases with chain length of molecules, as they get longer they tangle and take longer to move past each other and the mixture becomes more solid-like. It is a fluid as long as it is able to move. Viscosity causes problems making plastics through polymerisation.

Both surface tension and viscosity decrease with temperature, you will decrease the number of interactions and for helping viscosity you give the molecules energy that allow the bonds in the molecule to rotate more easily and the molecule to generally move faster, this particularly helps decrease viscosity as the ability to change conformation helps untangle.

Cornstarch is a polymer, therefore viscous, and has lots of hydroxyl groups, so the interaction with itself and water is high, so it is viable for this.

It was, indeed, cornstarch and water.

thats so… confusing.  I wish there was an easier way of explaning this stuff!  Im more of an Astronomy and Astrology kind of guy… or a videio game designer… one of those.

DJ, you’re still young too. Wait till you get into college and start taking some advanced courses and it’ll make a bit more sense to you. You may end up needing that knowledge someday if you play to design and program video games. It’ll come in handy when doing water and other fluid simulations.

Incidentally, I should point out for the regulars that DJ is my nephew.

D.J. Pickle - I could explain it better if you (or any SEB commenter) wishes, just email me by clicking on my name, in fact if you prefer I can email lecture slides.

Despite my comments being long it’s the most summarised way I can find of covering a lot of ground, and I admit the intensity of it can look intimidating but don’t let it be so. I am conditioned to lecures where this kind of thing is pumped out at me, being used to it helps but I myself have to read the notes slowly in my own time and look things up, there’s just so much to say.

Actually being an astronomer you could help me on something I’m stuck on if you like, look up the entry “Fun with non-Newtonian fluids.
It’s looking like a Green Christmas round these parts”.

A video game designer- sounds interesting, playing games is my only form of entertainment but my computer skills arn’t up to much and my creativity is somewhat drowned out as of late by volume of work. I have heard someone say, but I’m not sure if it’s true, that people who spend a lot of time playing video games are statistically more likely to become chemists, I don’t know why that is, it would just be a broad sweeping trend.

Best wishes, DC

Ok thanks!  I’m good for right now though, being a teenager who doesn’t know much is probibly the best time in my life to mess around!  You can do stupid retarded stuff and not get hurt that badly or if you do get hurt that badly, you can heal faster!  Or thats what ive been told, besides hurting your self can be quite fun!(I know you probibly think im nuts but sometimes ya just gota do something even if you will get hurt just to see what it would feel like or seem like.)

You can do stupid retarded stuff and not get hurt that badly or if you do get hurt that badly, you can heal faster!

Uh, you’ve checked Les’s archives, haven’t you?

A video game designer- sounds interesting

Particularly breast physics. There’s an amazing amount of research being done to make virtual boobs jiggle just so. And not just video games:

Sports bra ad

Hey, how’s that for topic drift?

OK I’ll email some stuff on atomic orbitals as a starter, unfortuantely with chemistry the fundamentals have their routes in quantum mechanics, I will tell you the rules that are essential for bonding (and therefore necessary to make a molecule) but unlike the lecturers I have I will tell you from the start that I don’t know why some of these rules are the case

“You can do stupid retarded stuff and not get hurt that badly or if you do get hurt that badly, you can heal faster!  Or thats what ive been told, besides hurting your self can be quite fun”

Experimentings healthy and you sound prepared, in general if something bad happens think why, mistakes are an acceptable part of being human in my book though.

Physically hurting yourself is not healthy, it is a release of great emotional stress for little physical harm, but as one of my mistakes (mostly last year in term time) it’s not the solution and distresses people, as well as that once you do it your inhibition to do it again falls, and the effect per damage is less the next time. If you ever find yourself in the position of wanting to, at least restrain and deal with what is causing the issue, you will come out of it a stronger person, and it will end, I promise.

I need to say that a common perception of what makes people strong is being ‘strong willed’, in my view this is completely wrong, instead what I consider makes someone strong is:
1)self restraint under need to do something harmful to others whether intended as the direct effect (malicious) or not (ie suicide)
2)minimise damage to yourself in adverse situations without passing it onto anyone else, in other words if you’re not wrong don’t criticise yourself but don’t retaliate
3)extra degree of freedom from psychological needs; if all needs were always satisfied we wouldn’t be patient and wouldn’t be able to think outside the box of needs

elwedriddsche - “Particularly breast physics”

I wonder if there are viscosity/rheology measurements on breasts and how flow, bounciness and elasticity changes with temperature? Perhaps there is a glass transition temperature below which they become brittle and easily shatter on aplication of force. I wonder what pressure would be needed to overcome surface tension and penetrate. I will have to try that

DJ Pickle - I’ve got some stuff for you in a word document, but I can’t find a way to send it to you

DC, if you don’t mind sharing, you can attach it to a wiki entry:

http://stupidevilbastard.com/index/wiki

Upload the file, create a page, and put the link on the page.

Cheers elwedriddsche,
I think it’s uploaded, anyone interested try
Quicklink = [[File:Introduction_to_the_atom.doc]]
Or search for the page ‘Introduction to the atom’

That was a pretty cool video.  Wouldn’t mind trying that out myself.

DJ: I wish I had been as interested in science when I was younger.  I never gave a crap about school till I got to college.  Boy was that mistake! 

Not only did I have to learn the stuff my teachers went over in class, but I had to learn all the stuff I missed in High School.  The smartest thing you could do is work your ass of now, so it is easier on you down the road.