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.

Arts & Entertainment
A stranger calls: Martin Freeman in ‘Fargo’
tvReview: New 10-part series brims with characters and stories

Arts & Entertainment
Shaun Evans as Endeavour interviews a prisoner as he tries to get to the bottom of a police cover up
Review: Second series comes to close with startling tale of police corruption and child abuse
Sport
Raheem Sterling and Luis Suarez celebrate during Liverpool's game with Norwich
football Another hurdle is out of the way for Brendan Rodgers' side
Arts & Entertainment
Schwarzenegger winning Mr. Universe 1969
arts + entsCan you guess the celebrity from these British Pathe News clips?
VIDEO
News
Portrait of Queen Elizabeth-II by David Bailey which has been released to mark her 88th birthday
peoplePortrait released to mark monarch's 88th birthday
Arts & Entertainment
The star of the sitcom ‘Miranda’ is hugely popular with mainstream audiences
TVMiranda Hart lined up for ‘Generation Game’ revival
Life & Style
The writer, Gerda Saunders, with her mother, who also suffered with dementia before her death
healthGerda Saunders on the most formidable effect of her dementia
Sport
Manchester United manager David Moyes looks on during his side's defeat to Everton
footballBaines and Mirallas score against United as Everton keep alive hopes of a top-four finish
Sport
Tour de France 2014Sir Rodney Walker on organising the UK stages of this year’s race
Arts & Entertainment
Jessica Brown Findlay as Mary Yellan in ‘Jamaica Inn’
TVJessica Brown Findlay on playing the spirited heroine of Jamaica Inn
News
YouTube clocks up more than a billion users a month
mediaEuropean rival Dailymotion certainly thinks so
Arts & Entertainment
The original design with Charles' face clearly visible, which is on display around the capital
arts + ents
Arts & Entertainment
‘Self-Portrait Worshipping Christ’ (c943-57) by St Dunstan
books How British artists perfected the art of the self-portrait
News
People
News
Sir Cliff Richard is to release his hundredth album at age 72
PEOPLE
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 iPad app?
Independent Dating
and  

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

iJobs Job Widget
iJobs General

Geography Teacher

£130 - £140 per day: Randstad Education Ilford: Secondary Geography Teacher Lo...

Do you want to work in Education?

£55 - £70 per day: Randstad Education Cheshire: Are you a dynamic and energeti...

SEN Teaching Assistant

Negotiable: Randstad Education Group: SEN TAs, LSAs and Support Workers needed...

Private Client Senior Manager - Sheffield

£50000 - £60000 per annum: Pro-Recruitment Group: The Sheffield office of this...

Day In a Page

Rubin ‘Hurricane’ Carter: The man who could have been champion of the world - and the Bob Dylan song that immortalised him

The man who could have been champion of the world

Rubin ‘Hurricane’ Carter and the Bob Dylan song that immortalised him
Didn’t she do well?

Didn’t she do well?

Miranda Hart lined up for ‘Generation Game’ revival
The Middle East we must confront in the future will be a Mafiastan ruled by money

The Middle East we must confront in the future will be a Mafiastan ruled by money

In Iraq, mafiosi already run almost the entire oil output of the south of the country
Before they were famous

Before they were famous

Can you guess the celebrity from these British Pathe News clips?
Martin Freeman’s casting in Fargo is genius

Martin Freeman’s casting in Fargo is a stroke of genius

Series is brimming with characters and stories all its own
How I brokered a peace deal with Robert Mugabe: Roy Agyemang reveals the delicate diplomacy needed to get Zimbabwe’s President to sit down with the BBC

How I brokered a peace deal with Robert Mugabe

Roy Agyemang reveals the delicate diplomacy needed to get Zimbabwe’s President to sit down with the BBC
Video of British Muslims dancing to Pharrell Williams's hit Happy attacked as 'sinful'

British Muslims's Happy video attacked as 'sinful'

The four-minute clip by Honesty Policy has had more than 300,000 hits on YouTube
Church of England-raised Michael Williams describes the unexpected joys in learning about his family's Jewish faith

Michael Williams: Do as I do, not as I pray

Church of England-raised Williams describes the unexpected joys in learning about his family's Jewish faith
A History of the First World War in 100 moments: A visit to the Front Line by the Prime Minister's wife

A History of the First World War in 100 moments

A visit to the Front Line by the Prime Minister's wife
Comedian Jenny Collier: 'Sexism I experienced on stand-up circuit should be extinct'

Jenny Collier: 'Sexism on stand-up circuit should be extinct'

The comedian's appearance at a show on the eve of International Women's Day was cancelled because they had "too many women" on the bill
Cannes Film Festival: Ken Loach and Mike Leigh to fight it out for the Palme d'Or

Cannes Film Festival

Ken Loach and Mike Leigh to fight it out for the Palme d'Or
The concept album makes surprise top ten return with neolithic opus from Jethro Tull's Ian Anderson

The concept album makes surprise top ten return

Neolithic opus from Jethro Tull's Ian Anderson is unexpected success
Lichen is the surprise new ingredient on fine-dining menus, thanks to our love of Scandinavian and Indian cuisines

Lichen is surprise new ingredient on fine-dining menus

Emily Jupp discovers how it can give a unique, smoky flavour to our cooking
10 best baking books

10 best baking books

Planning a spot of baking this bank holiday weekend? From old favourites to new releases, here’s ten cookbooks for you
Jury still out on Manchester City boss Manuel Pellegrini

Jury still out on Pellegrini

Draw with Sunderland raises questions over Manchester City manager's ability to motivate and unify his players