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.

News
people'It can last and it's terrifying'
Sport
Danny Welbeck's Manchester United future is in doubt
footballGunners confirm signing from Manchester United
Sport
footballStriker has moved on loan for the remainder of the season
Sport
footballFeaturing Bart Simpson
PROMOTED VIDEO
New Articles
Olivia Colman topped the list of the 30 most influential females in broadcasting
tv
News
Kelly Brook
peopleA spokesperson said the support group was 'extremely disappointed'
News
The five geckos were launched into space to find out about the effects of weightlessness on the creatures’ sex lives
i100
Life and Style
techIf those brochure kitchens look a little too perfect to be true, well, that’s probably because they are
Sport
Andy Murray celebrates a shot while playing Jo-Wilfried Tsonga
TennisWin sets up blockbuster US Open quarter-final against Djokovic
Arts and Entertainment
Hare’s a riddle: Kit Williams with the treasure linked to Masquerade
booksRiddling trilogy could net you $3m
Arts and Entertainment
Alex Kapranos of Franz Ferdinand performs live
music Pro-independence show to take place four days before vote
News
ebooksAn unforgettable anthology of contemporary reportage
News
news Video - hailed as 'most original' since Benedict Cumberbatch's
News
i100
Life and Style
The longer David Sedaris had his Fitbit, the further afield his walks took him through the West Sussex countryside
lifeDavid Sedaris: What I learnt from my fitness tracker about the world
Arts and Entertainment
Word master: Self holds up a copy of his novel ‘Umbrella’
booksUnlike 'talented mediocrity' George Orwell, you must approach this writer dictionary in hand
News
i100
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

SQL Implementation Consultant (VB,C#, SQL, Java, Eclipse, integ

£40000 - £50000 per annum + benefits+bonus+package: Harrington Starr: SQL Impl...

SQL Technical Implementation Consultant (Java, BA, Oracle, VBA)

£45000 - £55000 per annum + Benefits + Bonus: Harrington Starr: SQL Technical ...

Head of IT (Windows, Server, VMware, SAN, Fidessa, Equities)

£85000 per annum: Harrington Starr: Head of IT (Windows, Server, VMware, SAN, ...

Lead C# Developer (.Net, nHibernate, MVC, SQL) Surrey

£55000 - £60000 per annum + Benefits + Bonus: Harrington Starr: Lead C# Develo...

Day In a Page

'I’ll tell you what I would not serve - lamb and potatoes': US ambassador hits out at stodgy British food served at diplomatic dinners

'I’ll tell you what I would not serve - lamb and potatoes'

US ambassador hits out at stodgy British food
Radio Times female powerlist: A 'revolution' in TV gender roles

A 'revolution' in TV gender roles

Inside the Radio Times female powerlist
Endgame: James Frey's literary treasure hunt

James Frey's literary treasure hunt

Riddling trilogy could net you $3m
Fitbit: Because the tingle feels so good

Fitbit: Because the tingle feels so good

What David Sedaris learnt about the world from his fitness tracker
Saudis risk new Muslim division with proposal to move Mohamed’s tomb

Saudis risk new Muslim division with proposal to move Mohamed’s tomb

Second-holiest site in Islam attracts millions of pilgrims each year
Alexander Fury: The designer names to look for at fashion week this season

The big names to look for this fashion week

This week, designers begin to show their spring 2015 collections in New York
Will Self: 'I like Orwell's writing as much as the next talented mediocrity'

'I like Orwell's writing as much as the next talented mediocrity'

Will Self takes aim at Orwell's rules for writing plain English
Meet Afghanistan's middle-class paint-ballers

Meet Afghanistan's middle-class paint-ballers

Toy guns proving a popular diversion in a country flooded with the real thing
Al Pacino wows Venice

Al Pacino wows Venice

Ham among the brilliance as actor premieres two films at festival
Neil Lawson Baker interview: ‘I’ve gained so much from art. It’s only right to give something back’.

Neil Lawson Baker interview

‘I’ve gained so much from art. It’s only right to give something back’.
The other Mugabe who is lining up for the Zimbabwean presidency

The other Mugabe who is lining up for the Zimbabwean presidency

Wife of President Robert Mugabe appears to have her sights set on succeeding her husband
The model of a gadget launch: Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed

The model for a gadget launch

Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed
Alice Roberts: She's done pretty well, for a boffin without a beard

She's done pretty well, for a boffin without a beard

Alice Roberts talks about her new book on evolution - and why her early TV work drew flak from (mostly male) colleagues
Get well soon, Joan Rivers - an inspiration, whether she likes it or not

Get well soon, Joan Rivers

She is awful. But she's also wonderful, not in spite of but because of the fact she's forever saying appalling things, argues Ellen E Jones
Doctor Who Into the Dalek review: A classic sci-fi adventure with all the spectacle of a blockbuster

A fresh take on an old foe

Doctor Who Into the Dalek more than compensated for last week's nonsensical offering