technoquest

Q Why does bread rise?

A.Yeast makes bread rise. When cereal grain is ground to make flour, starch inside the grain is exposed. Adding water activates enzymes - amylases - which turn some of the starch into glucose. Yeast added to the dough uses the glucose to produce carbon dioxide and alcohol. If yeast has no oxygen, it will produce more alcohol than you want, which is why bread is kneaded to trap air inside it, and why dough often smells like barley hops. The carbon dioxide produced by the yeast is trapped in bubbles which make the bread light. The alcohol evaporates during baking - fortunately!

Q Can gold be turned into lead or vice versa?

A Elements such as gold and lead are characterised by the number of protons and neutrons in their nucleus - their atomic mass. By adding protons to the atom, chemists can theoretically turn lighter gold atoms with 79 protons into heavier lead atoms with 82 protons. Converting gold into lead takes a lot of energy and so costs more than the value of the lead created. The reverse process of converting heavier lead atoms into lighter gold atoms is also possible. Tampering with elements at an atomic level is more likely to produce radioactively unstable atoms of a new element rather than sparkling gold.

Q. Why doesn't glue dry out in a glue pot?

A Glue is made up of the glue that sticks and a solvent that keeps it liquid. When you put glue on paper, the solvent evaporates until the glue becomes sticky. There's a limit to the amount of solvent that can evaporate to fill the space in the bottle above the glue. Once the space is full of gas, no more solvent evaporates and the glue stays runny.

Q How does a water softener work?

A Water softeners work using a principle called ion exchange. Magnesium and calcium ions in the water are replaced with sodium ions from sodium chloride in the water softener. The magnesium and calcium ions prefer to be joined to the chloride ions in the water softener and the sodium ions prefer to end up in the water. Removing magnesium and chloride stops limescale forming on taps and inside kettles.

Q If an insect has a head, thorax and abdomen, what are the body parts of a spider called?

A In insects, the head, the thorax and the abdomen are separate. In spiders, the head and thorax are continuous, forming something called the prosoma. Eight legs are attached to the prosoma and their abdomen is joined to it at the lower end.

Q Why does chopping onions make you cry?

A The answer to this was only discovered fairly recently. Research done by Spaere and Vitonen in 1963 showed that when you chop an onion, you break open some of the onion's cells. This releases enzymes which take part in complex biochemical reactions. One of these produces a substance called propenyl sulphuric acid. This is a very volatile irritant. It "fumes" up from the onion and irritates your eyes.

Questions and answers are provided by Science Line. You can use its Dial-A-Scientist service on 0345 600444.

PROMOTED VIDEO
News
peopleGerman paper published pictures of 18-month-old daughter
Arts and Entertainment
'A voice untroubled by time': Kate Bush
musicKate Bush set to re-enter album charts after first conerts in 35 years
Life and Style
tech
Arts and Entertainment
Robin Williams' life story will be told in a biography written by a New York Times reporter
arts + ents
News
i100
Life and Style
food + drink
Life and Style
News
ebooksAn evocation of the conflict through the eyes of those who lived through it
Voices
voices
Sport
Roger Federer is greeted by Michael Jordan following his victory over Marinko Matosevic
tennisRoger Federer gets Michael Jordan's applause following tweener shot in win over Marinko Matosevic
News
peopleJustin Bieber accuses paparazzi of acting 'recklessly' after car crash
News
people
Arts and Entertainment
Oppressive atmosphere: the cast of 'Tyrant'
tvIntroducing Tyrant, one of the most hotly anticipated dramas of the year
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
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

Merger and Acquisition Project Manager

£500 - £550 Per Day: Clearwater People Solutions Ltd: Our client are currently...

Technical Manager – Heat Pumps

£40000 Per Annum dependent on experience: The Green Recruitment Company: They ...

Test Job

TBC: Test Recruiter for iJobs: Job London (Greater)

Senior Developer - HTML, CSS, PHP, JavaScript, VBA, SQL

£30000 - £35000 per annum + benefits: Ashdown Group: We are working with one o...

Day In a Page

Kate Bush, Hammersmith Apollo music review: A preamble, then a coup de théâtre - and suddenly the long wait felt worth it

Kate Bush shows a voice untroubled by time

A preamble, then a coup de théâtre - and suddenly the long wait felt worth it
Robot sheepdog technology could be used to save people from burning buildings

The science of herding is cracked

Mathematical model would allow robots to be programmed to control crowds and save people from burning buildings
Tyrant: Is the world ready for a Middle Eastern 'Dallas'?

This tyrant doesn’t rule

It’s billed as a Middle Eastern ‘Dallas’, so why does Fox’s new drama have a white British star?
Rachael Lander interview: From strung out to playing strings

From strung out to playing strings

Award-winning cellist Rachael Lander’s career was almost destroyed by the alcohol she drank to fight stage fright. Now she’s playing with Elbow and Ellie Goulding
The science of saturated fat: A big fat surprise about nutrition?

A big fat surprise about nutrition?

The science linking saturated fats to heart disease and other health issues has never been sound. Nina Teicholz looks at how governments started advising incorrectly on diets
Emmys 2014 review: Can they genuinely compete with the Oscars

Can they genuinely compete with the Oscars?

The recent Emmy Awards are certainly glamorous, but they can't beat their movie cousins
On the road to nowhere: A Routemaster trip to remember

On the road to nowhere

A Routemaster trip to remember
Hotel India: Mumbai's Taj Mahal Palace leaves its darker days behind

Hotel India

Mumbai's Taj Mahal Palace leaves its darker days behind
10 best pencil cases

Back to school: 10 best pencil cases

Whether it’s their first day at school, uni or a new project, treat the student in your life to some smart stationery
Arsenal vs Besiktas Champions League qualifier: Gunners know battle with Turks is a season-defining fixture

Arsenal know battle with Besiktas is a season-defining fixture

Arsene Wenger admits his below-strength side will have to improve on last week’s show to pass tough test
Pete Jenson: Athletic Bilbao’s locals-only transfer policy shows success does not need to be bought

Pete Jenson: A Different League

Athletic Bilbao’s locals-only transfer policy shows success does not need to be bought
This guitar riff has been voted greatest of all time

The Greatest Guitar Riff of all time

Whole Lotta Votes from Radio 2 listeners
Britain’s superstar ballerina

Britain’s superstar ballerina

Alicia Markova danced... every night of the week and twice on Saturdays
Berlin's Furrie invasion

Berlin's Furrie invasion

2000 fans attended Eurofeurence
‘It was a tidal wave of terror’

‘It was a tidal wave of terror’

Driven to the edge by postpartum psychosis