Behind the science: How echo-location works

To use echo-location efficiently it takes many hours of practice and a huge amount of determination but in the space of just half an hour Visibility’s Alex Campbell was able to teach me the basics of how it works.

The first thing you have to learn is how to produce a decent tongue click. Place your tongue on the roof of your mouth, just behind your front teeth and create a suction vacuum. When that vacuum breaks, it should emit a short sharp click.



Echo-location tends to come easiest to people whose sight is completely impaired.



It’s often hard for sighted people to concentrate on just using their ears. Partially-sighted people are also, understandably, taught to make the most of what vision they have left so echo-location can take extra work.



To help me forget about what I was seeing with my eyes, Alex gave me a blindfold which helped filter out any distractions.



Human ears are incredibly sophisticated. In fact we hear much better than we see. Unlike many animals, our eyes can’t take in infra-red or ultra-violet. But our ears can cope with around ten octaves. Place yourself in what you think is a completely silent room and you will in fact notice that we’re never in silence – if the room is quiet enough you should be able to hear your heart beating.



The first object we tried to find using the clicks was a flat, plastic tea tray which every so often Alex would place in front of my face. I would emit clicks every couple of seconds and my task was to grab the tray when I thought it was in front of me.



Amazingly it worked almost every time. It’s difficult for sighted people to describe sounds in detail – it’s something we’re simply not used to doing. Part of what an echo-location instructor teaches you is the language of trying to understand what you hear.



But all I can say is that every time the tray was placed in front of me the sound changed and somehow I knew it was there.



Next we tried a solid wall. I had to walk towards the wall and stop without bumping into it. Unlike the tray I struggled to find the wall. So instead we tried walking into the corner of a room and that was much easier. With the sounds waves bouncing off two surfaces, it was much easier to spot when the wall was close.



Next I was told to walk alongside a wall and find the opening in a door. Again this was relatively simple to do. We then walked from a large room into a small room where the sound change, unsurprisingly, was particularly pronounced.



After that it’s simply a case of trial and error and learning to master as many sounds as possible. That’s when the hard work really begins.

Suggested Topics
Start your day with The Independent, sign up for daily news emails
ebooks
ebooksAn introduction to the ground rules of British democracy
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
SPONSORED FEATURES
Independent Dating
and  

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

iJobs Job Widget
iJobs General

Recruitment Genius: Clinical Lead / RGN

£40000 - £42000 per annum: Recruitment Genius: This is an exciting opportunity...

Recruitment Genius: IT Sales Consultant

£35000 - £40000 per annum: Recruitment Genius: This IT support company has a n...

Recruitment Genius: Works Engineer

Negotiable: Recruitment Genius: A works engineer is required in a progressive ...

Recruitment Genius: Trainee Hire Manager - Tool Hire

£21000 - £25000 per annum: Recruitment Genius: Our client is seeking someone w...

Day In a Page

Isis profits from destruction of antiquities by selling relics to dealers - and then blowing up the buildings they come from to conceal the evidence of looting

How Isis profits from destruction of antiquities

Robert Fisk on the terrorist group's manipulation of the market to increase the price of artefacts
Labour leadership: Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea

'If we lose touch we’ll end up with two decades of the Tories'

In an exclusive interview, Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea
Tunisia fears its Arab Spring could be reversed as the new regime becomes as intolerant of dissent as its predecessor

The Arab Spring reversed

Tunisian protesters fear that a new law will whitewash corrupt businessmen and officials, but they are finding that the new regime is becoming as intolerant of dissent as its predecessor
King Arthur: Legendary figure was real and lived most of his life in Strathclyde, academic claims

Academic claims King Arthur was real - and reveals where he lived

Dr Andrew Breeze says the legendary figure did exist – but was a general, not a king
Who is Oliver Bonas and how has he captured middle-class hearts?

Who is Oliver Bonas?

It's the first high-street store to pay its staff the living wage, and it saw out the recession in style
Earth has 'lost more than half its trees' since humans first started cutting them down

Axe-wielding Man fells half the world’s trees – leaving us just 422 each

However, the number of trees may be eight times higher than previously thought
60 years of Scalextric: Model cars are now stuffed with as much tech as real ones

60 years of Scalextric

Model cars are now stuffed with as much tech as real ones
Theme parks continue to draw in thrill-seekers despite the risks - so why are we so addicted?

Why are we addicted to theme parks?

Now that Banksy has unveiled his own dystopian version, Christopher Beanland considers the ups and downs of our endless quest for amusement
Tourism in Iran: The country will soon be opening up again after years of isolation

Iran is opening up again to tourists

After years of isolation, Iran is reopening its embassies abroad. Soon, there'll be the chance for the adventurous to holiday there
10 best PS4 games

10 best PS4 games

Can’t wait for the new round of blockbusters due out this autumn? We played through last year’s offering
Transfer window: Ten things we learnt

Ten things we learnt from the transfer window

Record-breaking spending shows FFP restraint no longer applies
Migrant crisis: UN official Philippe Douste-Blazy reveals the harrowing sights he encountered among refugees arriving on Lampedusa

‘Can we really just turn away?’

Dead bodies, men drowning, women miscarrying – a senior UN figure on the horrors he has witnessed among migrants arriving on Lampedusa, and urges politicians not to underestimate our caring nature
Nine of Syria and Iraq's 10 world heritage sites are in danger as Isis ravages centuries of history

Nine of Syria and Iraq's 10 world heritage sites are in danger...

... and not just because of Isis vandalism
Girl on a Plane: An exclusive extract of the novelisation inspired by the 1970 Palestinian fighters hijack

Girl on a Plane

An exclusive extract of the novelisation inspired by the 1970 Palestinian fighters hijack
Why Frederick Forsyth's spying days could spell disaster for today's journalists

Why Frederick Forsyth's spying days could spell disaster for today's journalists

The author of 'The Day of the Jackal' has revealed he spied for MI6 while a foreign correspondent