BBC Focus

REPLY

Your opinions on science, technology and BBC Focus

ILLUSTRATION: ADAM GAL

E

FOCUS OCTOBER 2 016

Logic of logarithms

Neelofer Banglawalareferredto

John Napier as the inventor of

logarithms(August,p 107 ).

The purists among us wouldof

course insist that logarithms have

always existed! However, it tooka

mathematicalgeniuslikeNapier

todiscover their presence.

Fraser Gillespie, Dumbarton

Sticky fingers

Regarding Helen Czerski’s

problem withopeningplastic

bags in supermarkets(August,

p 55 ),Iwastoldafew years agoby

someone ‘in theknow’ that there

isatrickto opening thebags

withouthaving wetfingers. Ifyou

takethehandles ofthebag in your

handsandgentlybutfirmlypull

them apart this opens up the

inner corners of the bag enough to

get yourfingers in.

Also, could Helenprovide any

explanation as to whychildren’s

handsarealways sticky, no m at te r

what youdotoclean them?!

Will Hatton, via email

Not even science can solve the problem

of kids’ sticky fingers! – Ed

MESSAGE OF THE MONTH

[email protected]

,BBC Focus, Tower House,

Fairfax Street, Bristol, BS1 3BN

@sciencefocus

http://www.facebook.com/sciencefocus

Diesel engines: not always a cleaner option

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Smoke signal

Robert Matthews’ articleondieselpollution

(September, p81)appears tobebased on some

very controversial ‘science’. In 2014 there

were 36,000deathsfromlung cancer in the

UK, thevastmajorityofthosebeingheavy

tobacco smokers. He now tellsusthere are

50,000 additionaldeathsper yearfrom

inhalation ofNOx andparticlesfromdiesel

engines. This can only be true if millions of

people have taken upthe habit of inhaling

directlyfromdieselexhaustpipes.

He then states thatdieselcars arebigger and

heavier thanpetrol cars. They are the same size as

their equivalent petrol-poweredsiblings andon

average about fiveper cent heavier. A BMW 320i

weighs1,505kganda320dweighs1,580kg,but

the320iusesabout 30 per cent morefuel,so

producing 30 per cent more CO 2. When I drive

from Calais to Munich, I can do the tripwithout

stopping for fuel in my 320d, but this would be

impossibleina320i.

Ibelieve thesedeathfigures are untrue,but in

any case mostdieselpollution is comingfrom

lorries, taxis,buses andofcourse ships. Ifyou

want to outlaw suchefficient vehicles you will

put theUKoutofbusinessinnotimeflat.

Dan Parker, Cobham

The mortality figures come from the government’s own

policy paper on the subject (bit.ly/2bU6rRJ). I too found them

shocking, but not nearly as shocking as the determination of

some motor manuf ac turer s to put prof it ahead of public health.

• Prof Robert Matthews, BBC Focus columnist

yourfix ofscience and tech? The Science

Focus website is packedwithnews,

articles andQ&As tokeep yourbrain

satisffdied.scifiencefocus.com

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