Science: Technoquest

Questions and answers provided by Science Line's Dial-a-Scientist on 0345 600444

Q Why are our elbows better than our hands when testing the temperature of babies' bath water?

A Although there are more nerve endings in the hands and feet, the skin in these regions is usually quite thick and shields our skin temperature receptors from any temperature we are trying to measure. Using a region of our body which has thinner skin is more effective. It also leaves your hands free to hold the baby.

Q How and why do frogs sing? Is it because they're territorial?

A Frogs have a larynx and vocal chords like other vertebrates, so sound production is essentially the same as in humans, birds and mammals. However, different species show a range of singing ability, from virtually silent to very loud calls. They probably sing for several reasons - advertising for a mate, intimidating predators or even to get other males to release them from a mating embrace. Generally, males call and females stay silent - or quietly call back to let the male know they're there. Some frogs are territorial only in the breeding session, while others may guard an area all year round.

Q How does a Venus fly trap digest a fly?

A When a fly enters the Venus fly trap, it knocks a trigger hair that sets the trap. It's not until the fly moves again and triggers another hair that the trap is sprung and the plant closes its "jaws". Once the jaws are closed, the plant lets out digestive juices which dissolve the fly. The juices and dissolved fly are absorbed by the plant. This is similar to how food is digested in our stomachs.

Q How does water move around in a tree?

A Water molecules are very good at sticking together - where one goes, the rest will follow. This is called surface tension. When you pull on one molecule, the rest tend to move, too. Water is sucked out of the tree by evaporation from its leaves; this pulls water up from the roots.

Q Why do male spiders let themselves be eaten by females after mating?

A Only a few species of spider go through this bizarre ritual. The males often try to escape, but as females are many times larger, this is not easy. The males' drive to pass on their genes to the next generation is greater than their desire to live long but ultimately mortal lives. Sacrificing themselves to the female also provides her with extra nutrition, improving her chances of fathering his offspring.

Start your day with The Independent, sign up for daily news emails
Arts and Entertainment
The Doctor and Clara have their first real heart to heart since he regenerated in 'Deep Breath'
TV
Arts and Entertainment
James Hewitt has firmly denied being Harry’s father
arts + ents
Arts and Entertainment
Jamie Oliver
filmTV chef Jamie Oliver turned down role in The Hobbit
News
The official police photograph of Dustin Diamond taken after he was arrested in Wisconsin
peopleDownfall of the TV star charged with bar stabbing
PROMOTED VIDEO
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Sport
Ashley Barnes of Burnley scores their second goal
footballMan City vs Burnley match report
News
news
News
Sir James Dyson: 'Students must be inspired to take up the challenge of engineering'
i100
Arts and Entertainment
Man of action: Christian Bale stars in Exodus: Gods and Kings
film
Life and Style
Apple showed no sign of losing its talent for product launches with the new, slightly larger iPhone 6 making headlines
techSecurity breaches and overhyped start-ups dominated a year in which very little changed (save the size of your phone)
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Embedded Linux Engineer - C / C++

£35000 - £45000 per annum: Recruitment Genius: A well funded smart home compan...

Recruitment Genius: Senior Software Engineer - Python / Node / C / Go

£35000 - £45000 per annum: Recruitment Genius: *Flexible working in a relaxed ...

Recruitment Genius: Senior Bookkeeper

£20000 - £25000 per annum: Recruitment Genius: This accountancy firm have an e...

Recruitment Genius: Junior Developer / Mobile Apps / Java / C# / HTML 5 / JS

£17000 - £28000 per annum: Recruitment Genius: Junior Mobile Application Devel...

Day In a Page

A timely reminder of the bloody anniversary we all forgot

A timely reminder of the bloody anniversary we all forgot

Who remembers that this week we enter the 150th anniversary year of the end of the American Civil War, asks Robert Fisk
Homeless Veterans appeal: Former soldiers pay their respects to a friend who also served

Homeless Veterans appeal

Former soldiers pay their respects to a friend who also served
Downfall of Dustin 'Screech' Diamond, the 'Saved By The Bell' star charged with bar stabbing

Scarred by the bell

The downfall of the TV star charged with bar stabbing
Why 2014 was a year of technological let-downs

Why 2014 was a year of technological let-downs

Security breaches and overhyped start-ups dominated a year in which very little changed (save the size of your phone)
Cuba's golf revolution: But will the revolutionary nation take 'bourgeois' game to its heart?

Will revolutionary Cuba take 'bourgeois' golf to its heart?

Fidel Castro ridiculed the game – but now investment in leisure resort projects is welcome
The Locked Room Mysteries: As a new collection of the genre’s best is published, its editor Otto Penzler explains the rules of engagement

The Locked Room Mysteries

As a new collection of the genre’s best is published, its editor explains the rules of engagement
Amy Adams on playing painter Margaret Keane in Tim Burton's Big Eyes

How I made myself Keane

Amy Adams hadn’t wanted to take the role of artist Margaret Keane, because she’d had enough of playing victims. But then she had a daughter, and saw the painter in a new light
Ed Richards: Parting view of Ofcom chief. . . we hate jokes on the disabled

Parting view of Ofcom chief... we hate jokes on the disabled

Bad language once got TV viewers irate, inciting calls to broadcasting switchboards. But now there is a worse offender, says retiring head of the media watchdog, Ed Richards
A look back at fashion in 2014: Wear in review

Wear in review

A look back at fashion in 2014
Ian Herbert: My 10 hopes for sport in 2015. Might just one of them happen?

Ian Herbert: My 10 hopes for sport in 2015

Might just one of them happen?
War with Isis: The West needs more than a White Knight

The West needs more than a White Knight

Despite billions spent on weapons, the US has not been able to counter Isis's gruesome tactics, says Patrick Cockburn
Return to Helmand: Private Davey Graham recalls the day he was shot by the Taliban

'The day I was shot by the Taliban'

Private Davey Graham was shot five times during an ambush in 2007 - it was the first, controversial photograph to show the dangers our soldiers faced in Helmand province
Revealed: the best and worst airlines for delays

Revealed: the best and worst airlines for delays

Many flyers are failing to claim compensation to which they are entitled, a new survey has found
The stories that defined 2014: From the Scottish independence referendum to the Ice Bucket Challenge, our writers voice their opinions

The stories that defined 2014

From the Scottish independence referendum to the Ice Bucket Challenge, our writers voice their opinions
Stoke-on-Trent becomes first British city to be classified as 'disaster resilient' by the United Nations

Disaster looming? Now you know where to head...

Which British city has become the first to be awarded special 'resilience' status by the UN?