Will Dean's Ideas Factory: Can you really get smelly jeans clean in the freezer?

At the beginning of this month, The New York Times reported on an – actually quite worthy – new project from jean giant Levi Strauss in which it encouraged customers to save water by washing their jeans (which use 4,000 litres of water during their life- span, say Levi's) much less and, if they want to kill the germs on their trousers between wears – to bung them in the freezer.

All very worthwhile – though not, it must be said, a bad way to promote a new line of the firm's jeans that are said to requires less washing.

It was the line about sticking them in the freezer that intrigued most about the campaign though. We all know that freezing clothes is handy for one thing – getting chewing gum out of fabrics. But does it actually eradicate germs?

Er, no, reckons Stephen Craig Cary, Emeritus professor of marine biosciences at the University of Delaware, who wrote to the Smithsonian's Surprising Science blog to put the zipper on Levi's suggestion: "One might think that if the temperature drops well below the human body temperature they will not survive but actually many will. Many are preadapted to survive low temperatures."

Cary's suggestions are to raise the temperature to 121 degrees celsius for sterilisation or just to wash them as that would use less energy.

Which gives us three options (the third being just to get over ourselves and wear smelly jeans. Or make jeans that clean them- selves chemically?

Back over to you, Levi's.

Behold the 'urban beehive'

This device may look like a flowery urinal but it's much more beautiful than that. Honest.

Philips' "urban beehive" may sound like a Seinfeld episode name, but it's actually deadly serious. Installed through a small hole in the window, it allows the growing legions of enthusiasts to support the beedevilled insects by providing them with a home in dense cities. The quid pro quo is that you, as a proud urban beehive owner, can sup as much honey as the bees can produce. And you can see into the hive, too.

At the moment, the urban beehive is only a concept – part of Philips' Microbial Living project, which includes a "larder" (an evaporative cooler and vegetable storage system built into a dining table).

And of course considerations such as height and the number of plants nearby (not to mention apartment dwellers unleashing a swarm of bees on their neighbours) need to be thought about, but it could be the best thing to happen to the bee since yellow and black stripes were trendy.

Read more: ind.pn/beelife

Making the junk of industry pay

A few weeks ago The Ideas Factory looked at "dead" bicycles and how they were being repurposed. This is part of a wider trend of people making do and mend. But for Damon Carson, of Denver's Repurposed Materials, it's a chance to get old junk – from old billboard vinyl to conveyor belts – and make it into something useful and sell it on a profit).

One particularly smart invention, he told the Denver Post, is an old street-sweeper brush remade as a cattle brush and sold at a fraction of the cost of a bespoke one.

That may be more useful in the fields of Denver than the streets of Leeds, but it gives an idea of the potential to transform waste while saving cash – and the planet.

Read more: ind.pn/reusedenver

Smile! You're on campus – behind MIT's Mood Meter

You'd think that students at one of the world's most renowned research universities, the Massachusetts Institute of Technology (MIT), would be walking around with a smile on their faces just for getting a place there. But that's not the case, as two MIT graduate students –Javier Hernandez and M Ehsan Hoque – and their team have discovered through the creation of the MIT Mood Meter.

The Mood Meter consists of four cameras dotted around the campus that enable researchers from the Affective Computing Group at the college's media lab to track facial expressions and give the research team an idea of the general level of happiness across the university's campus.

As they explain in their blurb: "This project is intended to raise awareness of how our own smiles can positively affect the surrounding environment, and to assess how friendly MIT might appear as a community." They hope to use the technology to track how, for instance, exams or the state of the weather can make us smile or frown. How this would have affected Nat King Cole, who smiled even though his heart was aching, is unclear.

See more: ind.pn/mitmood

Send us your Ideas Factory fuel

The Ideas Factory is a weekly round-up of the best, weirdest and most interesting new discoveries, theories and experiments from around the world. If you have an idea you'd like to share, I'd love to hear from you. You can email me on w.dean@independent.co.uk or tweet me at @willydean.