Dave, Ben. I did the experiment, and got the correct result. I then repeated it, but this time i added soap to the water in the glass. I got the same ...

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Also, what is the difference between a rainproof and a stormproof coat? Is it the size of the "hole's" in the material, which i suppose...

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I think it is because soap reduces the surface tension, but doesn't actually kill it (soap bubbles are still pulled into spheres), and the holes ... Whole Thread | Post Reply

Living in a Material World...

When people hear the word 'Material' they mainly think of home economics classes and things, like cotton, that your clothes are made from.   We here at the Naked Scientists are looking into some new materials,  or how small changes in existing materials can make a big difference...

Super-Non-Stick Surfaces

Non-stick pans are great - the cooked on scrambled egg just slides right off - right?  Well, maybe not all the time, especially once the coating gets a bit scratched and you're left with no choice but to scrub away, taking off even more of the coating in the process.  Maybe not for much longer, as Ullrich Steiner, of the Thin Films and Interfaces group at Cambridge University, has found a way to make standard teflon even more non-stick.  By putting a series of tiny 'pits' into the surface of teflon, they have made a ultra-hydrophobic surface, meaning one which repells water very strongly.  Coating a spoon in this ultra-non-stick surface means that even honey won't stick to it, possibly heralding a new age for non-stick coatings.

Ullrich & team show that it's not just the chemical properties of a material that effect the way it interacts with other substances, but by changing the shape at a tiny scale, you can change the way it works. 

Surface properties also create some of the beautiful colours found in nature, such as a butterfly's wing or a kingfisher's feather.  Normally, a colour we see is the result of a material absorbing the light in certain frequencies, and reflecting only, say, red light back.  It's not easy to get something with the right chemical properties to give the resplendant blue in a butterfly's wing, so nature relies on something a little more cunning - structural colour.  A butterfly's wing, or a kingfisher's feather, has a microscale structure that reflects light in just such a way that we see beautiful blue colours.  If would want to see an example of structural colour at work, find someone with blue eyes (or look in a mirror if you're blue eyed yourself) and in the blue Iris, you can see structural colour at work.  It may be best to ask first, as staring into a colleagues eyes may have unintended results!

Plastic From Potatoes

Biocomposites, materials usually made from plant matter, could set us free from relying on petrochemical based plastics.  Paul Fowler, of the University of Bangor, has been developing plastics based on potato starch, which can be processed on existing machinery with just some minor adjustments.  Strong and durable, bioplastics could be a perfect alternative to petrol-based plastics and, as they are made from the starch we find in potatoes, are made from a renewable resource.  By controlling the materials which go into bioplastics, they can be made to perform different tasks - even with plastics that degrade 'on demand' - sprinkle some powder on your plastic and it returns to organic mush in no time.  Soon, you could be carrying your potatoes back from the shop, in a bag made from potatoes!

Electronic Paper and E-Ink

Every day, millions of people pick up their daily paper, read bits of it and, hopefully, recycle it when they're done.  Wouldn't it be easier to have just one paper, which fills with today's news every morning?  Plastic Logic, a Cambridge based company, are developing the technology to do just that.  A special kind of plastic, flexible and rugged, could be all you would ever need to read, and rather than relying on a backlight, which can make your eyes tired, this reflects light back to you, just like paper!  Electronic ink, or E-Ink, a system similar to LCD screens, means that your plastic paper can display any text, be it your daily paper or that holiday novel, and will wipe clean at the touch of a button.  It should be possible for you to carry a few novels, download your newspaper, maybe even carry maps or travel guides all in one convenient package!

Medical Materials

We're always being told to be careful what we put into our bodies - but what about when you have no choice?  If you should ever need a hip replacement, or need a bone pinned or plated, you would usually have to rely on titanium.  But metal implants are often too stiff, and wont form a direct chemical bond with the bone.  New materials for bone implants are being developed by the Centre for Medical Materials at Cambridge University, such as bioactive ceramics which have similar properties to bone, or polymers which will degrade over time, giving your body the chance to rebuild healthy tissue.  By implanting healthy cells on a scaffold of biodegradable polymer, you can actually encourage the body to repair the damage, rather than just plug the hole with a metal bar!

 

As always, we want your questions on materials, or any science topic, so get them in by emailing Chris@thenakedscientists.com