This Way Up for Saturday 17 December 2016

Will you ring my bells?! Also walking in the footsteps of ancient man, the truth about electric drills, and could the way you walk be an early warning of cognitive decline?

Ring my bells!

One of the oldest forms of mass communication – after smoke signals but before Snapchat – was the tradition of ringing church bells to signal what was happening in your neighbourhood.

The bells marked births and deaths, wars, feasts and marriages, a bit like a community noticeboard or a newspaper in the good old days before the printing press and the internet.

Even with uncapped broadband plans and free wifi to get the latest global updates, people are still ringing bells here in New Zealand! In fact, the country's featuring on bellringing bucket lists, with Dunedin having the southern-most bell tower in the world.

That's just one of the surprising things Simon Morton discovers on a visit to the Wellington Combined Society of Bellringers.

The ancient size-10 footprints that could rewrite history

The size-10 footprints discovered in Tanzania earlier this year date back 3.6 million years, and suggest our ancient ancestors were far larger than we thought.

Unearthing these footprints required no small amount of luck, says Dr Chris Smith.

They were discovered by accident when the Tanzanian government started exploring plans to build a visitor centre at the country's famed Laetoli site.

This is where back in 1978 British paleoanthropologist Mary Leakey discovered the first set of hominid footprints, thought to belong to the species Australopithecus afarensis.

What's astounding is the preservation of these prints was only possible after a layer of volcanic ash was dampened by seasonal rains to capture prints from hominids and animals walking over it. Then a later volcanic eruption sealed the area with more ash, preserving all these marks and indentations and capturing them in time.

The analysis of these new sets of prints has been published this week in the journal eLife. By looking at the depth of the footprints and their spacing, University of Perugia paleontologist Marco Cherin and the other researchers were able to tell the likely size of the walkers.

"We were shocked," Cherin says. "One of these individuals was over 165cm tall. That's equivalent with modern day humans. It means they [Australopithecus afarensis] were potentially much larger than we thought." 

Traditional theories suggest that ancient human relatives stayed relatively small until they started leaving Africa some 100,000 years ago.

"This shows that there was considerable body size variation, and probably sexual dimorphism [meaning size differences between male and female] as early as 3.66 million years ago," said Cherin. "We didn't expect that."

The truth about electric drills

Tis the season to be drilling...

If you're lining up some DIY jobs for the holidays and need to upgrade your drill, George Block from has some tips on the best on the market.

The advent of powerful lithium batteries and brushless DC motors mean these days drills are getting more efficient and powerful.

But they're not cheap, his advice is stay away from anything under $200, and for a decent bit of kit $350 is nearer the mark.

So what will $350 get you?

"You're going to be getting a drill with a brushless motor, those motors are historically confined to trade tools."
He likes the Ryobi one plus brushless range. 

"A good brushless drill that's almost a crossover trade/DIY unit, you can pick that up for $350 including 2 batteries that can be used in other tools. Every Ryobi one plus 18v tool that I've tested has been good. I've never seen a lemon in that range, they're a good bet for most of us." 

If that's a little rich for the budget, Makita has a drill with 2 batteries and a charger for $199. 

"Anything cheaper than that and you start getting some really undercooked drills."

He says factors to consider are voltage (18 volt is the most powerful) maximum torque, no load speed and battery power. No load speed is how fast the head spins when it's not drilling into anything.

But if you want something to assemble flatpack furniture or hang the odd picture, he suggests cordless screw drivers might be the answer.

"Cordless screw drivers were the break out stars of our tests this year" He likes the Worx for $90 from Mitre 10 and his favourite is the Black and Decker lithium 3.6 volt for $70.  

And if he had to pick one drill? 

"The Ryobi 18 volt compact R18 DD a really good drill, 90 percent of us are not going to want anything more."  

Movement and memory

A walk in the park

Photo: Source AFP

It turns out the way we move can tell us a lot about how well our brains are ageing. 

Neurologist Rodolfo Savica of the Mayo Clinic recently published a study linking gait with memory and cognitive decline.