Hello and welcome to this week's round-up of activity on The Last Word.

There has been a bit of a theme of throaty questions this week. juliaAS94 asked The Last Word why people get a lump at the back of their throat when they cry. Jon-Richfield suggested that it is the result of a muscle spasm, whereas our Facebook fans thought it might be due to peptides or simultaneous activation of sympathetic and parasympathetic nerves http://on.fb.me/aIseIE. Can you settle the debate? http://bit.ly/asGwOF?

More pharyngeal fun comes from Bryan Gilmour, who wonders why we become hoarse if we shout, and what happens when your voice recovers? http://bit.ly/aK3rj5?

And today's question takes a trip into the vocal cords of the animal kingdom, with translatrix's question: Does any other animal's voice pitch depend on its sex? http://bit.ly/bXJn2X

Some light relief from all that laryngeal action can be gained from cogitating on what might happen if you microwave a shoe. Have you ever tried? You can find the experimental set-up in the answers if you would like to give it a go yourself. Or apply your knowledge of materials science to suggest possible outcomes: http://bit.ly/9WD58B

Finally, LaexD has been wondering what your angular momentum is when you spin on an office chair. I can think of no better way to distract yourself on a Friday afternoon. Let me know how you get on if you try it for yourself – but be health and safety conscious if you do! http://bit.ly/ayKNon?

Don't forget that if you'd like to be notified of the daily questions from The Last Word, and for lots of other New Scientist content, become a fan of our Facebook page: http://www.facebook.com/newscientist

Wishing you an inquisitive and experimental weekend,

All the best,

Kat

Letters and comments editor, New Scientist

We all know that 2x/4x = 4x/8x does not tell us what x is because is cancelled out being referenced on both sides.

Describing  an egg as egg shaped does not tell us what the shape of an egg is.

So why do models gravity using a picture of a “gravity hole  in a mesh of time” as if the weight of a ball is distorting a frame of time. This, surly, is a circular reference effectively saying gravity looks like gravity. Additionally this model has some rather poor comparison’s. And if the mesh is three dimensional then what are the axis of this mesh?  Does this imply time have 3 dimension’s?  Showing a picture of a moving ball rotating around a gravity ball includes a reference to time to describe time itself. Giving two layers of self-reference.

Can anyone explain to the lay public what gravity is without using self-reference. ?

Vultures are able to use thermal currents in the air to give themselves lift and therefore save energy when searching for food.  

I have read that agglomerations of vultures occur on the fringes of settlements where animal carcasses are dumped. 

But would it be possible for vultures to benefit from urban heat islands?  If so, what is the evidence?

5 months ago I got the cartilage in the top of my ear pierced. I had persistant and numerous problems with infection and irritation. A number of people informed me that this is because it takes longer for cartilage to heal in the new shape. I have since removed the earring and the hole closed over and began to heal almost immediately. I have heard similar stories from people who have had theirs for years. So does this mean cartilage heals? and if so why did i have to have numerous torn pieces of cartilage removed from the meniscal discs in my knee? why didn't it heal?

Hello and welcome to this week's round-up of The Last Word!

Kicking off this week was a question from tsharek about the bees that frequent his vines. An individual bee will "warn him off" when he gets too close, which made him wonder: do some bees act as sentries for the rest of the swarm? The warning comes from an individual bee - what is it about the social structure of hives that determines that it is this particular bee? http://bit.ly/bou7at?

Might liposuction increase the risk of diseases such as diabetes, rjh wonders - if our fat cells actually protect us, could having liposuction actually put you at risk of a metabolic disease? See what our Last Worders have to say at http://bit.ly/cw4FZc? Why doesn't heat rub affect your fingers? Given how sensitive our fingertips are to touch and heat, why is it that when you apply heat rub creams you don't feel the burn on your hands the way you do on other body parts? Check it out at http://bit.ly/dvxoQy ? Are we going to run out of wireless bandwidth? It's a common refrain that with all the new bandwidth-hungry devices, and the mobile market expanding rapidly, that there is a shortage of spectrum. This is repeated often enough that it "must be true": But is it? http://bit.ly/apY32q?

And finally, we come full circle back to insects with today's question from BRidder: what do midges have for lunch when blood is not an option? http://bit.ly/9dHmac

Have a great weekend and see you on the flip side,

Kat

Letters and comments editor, New Scientist

PS: If anyone knows how best to fend off my cold, don't hold back with your Last Word wisdom!

Image: Jehane/Seq/Flickr

We started off the week with a murder mystery. In what looked like a ritual killing, aln found a possum carcass strangely laid out on his lawn in Sydney. The Last Word community got stuck in with their investigative skills http://bit.ly/arPf8M, as did our fans on facebook http://bit.ly/aBKe0O.

Do humming birds get brained by raindrops? ctbaldwin figured that as they're so little, and the raindrops around his neighbourhood in Texas are so big  the little guys might get knocked out, or at least knocked out of the sky. Read a comparison between the sizes of raindrops and bird brains at http://bit.ly/add8zW?

Getting a bit more technical, tbrucenyc heard that the overtones created by the vibration of strings on musical instruments are often sharp compared to the note to which they are tuned. Why are harmonic vibrations on piano and guitar strings often out of tune? A whole host of great explanations were provided by the Last Worders:? http://bit.ly/cVz0a2

LukeS knows there is a delay when watching live TV. Find out the causes, and the total time-delay for a live broadcast at http://bit.ly/bR0VsM

Finally, fieldo85 wonders why we often laugh when people hurt themselves. While some people may not find it funny, there's a lot of mileage in shows that broadcast hapless people in home videos. Why would we find accidents funny? Check it out and join the debate at http://bit.ly/b87zdZ

Do check out the New Scientist facebook group for more discussions, and become a fan to receive a daily Last Word question: http://www.facebook.com/newscientist

That's it for this week from me. It just remains to wish you an accident-free, possum-carnage free, and fun-filled weekend.

See you on the other side,

Kat

Letters and Comments editor, New Scientist

Though the middle A may be at 440 Hz, a grand piano will be increasingly flat in the lower octaves and increasingly sharp in the higher octaves.

All the strings have overtones sharp to their fundamentals. A piano tuner takes this into account when tuning.

A piano tuner told me this is referred to as temper.

Though well tempered scales are another matter.

Is the word temper correctly used here?

Why would the strings have overtones sharp to their fundamentals?

I have actually seen this effect displayed on a strobe tuner as outer rings of overtones rotating clockwise to the stationary fundamental.

Photo -  Bruce T