How It Works - UK (2020-02)

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Hearanyone’sheartbeatwiththisDIYstethoscopethatusestubingandfunnels

Make your own stethoscope

HOW TO...

Practical projects to try at home

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liabilityforanyadverseeffectsexperiencedduringthecourseofcarrying

outtheseprojectsoratanytimeafter.Alwaystakecarewhenhandling

potentiallyhazardousequipmentorwhenworkingwithelectronicsand

© followthemanufacturer’sinstructions.

Iustrat

ons

by

Ed

Crooks

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1

Stretch a balloon

First, cut off around one-third of a balloon

from the open end, and stretch the rest of it over a

small funnel. If you don’t have a balloon, you can

also use plastic w rap.

2

Secure it in place

Use some strong tape to secure the covering

in place – the more secure your covering, the more

effectively it will transfer the vibrations of a

heartbeat into a sound you can hear.

3

Add some tubing

Cut a 40-centimetre length of clear, plastic

tubing – you can get it in a hardware or garden

supply shop nd of the funnel

into the tub ly.

4

Add another funnel

Add another funnel at the other end of the

tube. You don’t have to cover this end with

another balloon, but you can if you like. Why not

tr y it without, then add a covering if needed.

5

Make it secure

Use strong tape to fix the second funnel to the

tube. Make it as airtight as possible – any big gaps

might mean the v ibrations from the heartbeat are

weakened slightly, and harder to hear.

6

Test it out

Put the covered endofthestethoscope over

your heart and the other end over your ear. What

can you hear? Tr y it on other people, and on

different parts of your body, like your neck.

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SUMMARY...

As your heart pumps blood around your body, valves in the heart open and close. These

valves cause vibrations that a stethoscope can detect. They cause the membrane – the

balloon – to vibrate, which causes vibrations in the air inside the stethoscope. These

vibrationstraveldowntheairinthetubeand your ear picks them up. As you exercise, the

heartbeatsfastertotransfermore blood around your body.

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7

Record your heart rate

If you have a stopwatch, you can recordyour

heart rate. Start the stopwatch and startcounting

the number of beats in 60 seconds. Tr y running

around for a minute and do it again.

Make a particle

detecting cloud

chamber

NEXT

ISSUE

“Try it on other

people, and on

different parts of

your body”