WHAT DID PEOPLE ALREADY KNOW? A person has a that can be felt through the skin. The ‘period’ of a (the time it takes to swing) A patient’s pulse might change when he/she is unwell. is determined by its length.

WHAT DID THE SCIENTIST NOTICE? The period of a pendulum could be the same as a person’s pulse.

WHAT QUESTION DO YOU THINK THE SCIENTIST ASKED? How can I change the length of the pendulum whilst it is in motion so that it matches the person’s pulse?

WHAT DID THE SCIENTIST DO? Santorio developed an instrument called a pulsilogium that could lengthen or shorten the pendulum whilst it was in motion. Santorio matched the pendulum’s swing to the patient’s pulse.

SANTORIO SANTORIO SANTORIO WHAT WOULD YOU DO NEXT?

WHAT DID THE SCIENTIST WHAT DID OTHER SCIENTISTS FIND OUT? DO NEXT? Santorio measured his patient’s pulse using a scale Scientists invented more reliable clocks and measured marked on the beam of his pulsilogium. He recorded the pulse by counting beats per minute (bpm). pulse of patients when they were healthy and compared Today we can use light to measure pulse and oxygen this with new readings when they became ill. levels in the blood. A TIMELINE FOR MEASURING PULSE C.130–210 AD 1515–1559 / 1578–1657 possible treatments, including‘bloodletting’. and usedthistodiagnosediseasesuggest Hemonitoredto theheart. pulsebyfeeling it blood buthedidnotthinkthatreturned Claudius ,discovered carry thatarteries A famous physician intheRoman Empire, CLAUDIUS GALEN lungs andtotheotherorgans. that bloodflows in 2separate loops: tothe William Harvey (1578-1657) the heart inonedirectionthe heart only. animal dissectionthatbloodflows through a Italianprofessor, discovered through Realdo Columbo(1515-1559), proved proved

1602–1609 1603 on itslength(notthesuspendedmass). pendulum (thetimeittakes toswing)depends pendulum. Herealised thatthe‘period’ofa Galileo investigated theproperties ofthe a numerical scale. a numerical in apatient’spulseas‘degrees’ on The using theproperties ofapendulum. instrument tomeasure pulseaccurately Santorio invented an pulsilogium recorded changes

1600–1670 count heart beatsperminute(bpm). count heart minute hands. There was no way to accurately accurately orreliably. Mostclocksdidnothave Clocks could notmeasure timeintervals short CLOCKS

1924 / 1942

CURRENT used inhospitalstomonitorpatients. pilots. Today, pulseoximeters are commonly oxygen content ofbloodinWorld War II meter (oximeter) toindirectly measure the Glenn Millikan (1942) today todetectcardiac problems. from beating.TheECG theheart isstillused changesontheskinarising tiny electrical first electrocardiogram (ECG), whichdetects Nobel Prize inMedicinefor inventing the Willem Einthoven (1924) Are theyreliable? What willtheytellus? Will we allwear them? What willtheymeasure inthefuture? FITNESS TRACKERS

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A TIMELINE FOR MEASURING PULSE C.130–210 AD 1515–1559 / 1578–1657 returned totheheart. bloodbuthedidnotthinkthat carry Claudius Galendiscovered thatarteries blood circulation? What didRomans know about including ‘bloodletting’. disease andtosuggestpossibletreatments, by feeling itandusedthistodiagnose Physicians monitored apatient’spulse disease? How didRoman doctors diagnose How didtheydiscover this? other organs. in 2separate loops:tothelungsand inonedirectionthe heart onlyanditflows They discovered thatbloodflows through They usedanimaldissection. about bloodcirculation? What diddoctors in1500sknow

1602–1609 1603 (period) dependsuponitslength. The timethependulumtakes toswing a pendulum? What didGalileonotice about His new instrument was called apulsilogium. His newinstrumentwascalled beat. heart pendulum wasmatchedwiththepatient’s He usedapendulum:theswingof measure hispatient’spulse? What didSantoriousetohelphim

1600–1670 minute hands. minute hands. accurately orreliably. Mostclocksdidnothave Clocks could notmeasure timeintervals short measured accurately inthe1600s? Why were beatsperminutenot heart

1924 / 1942

CURRENT arising from beating. theheart changesontheskin detect tinyelectrical (cardiac) problems.to detectheart ECGs Electrocardiograms (ECG) are usedtoday blood oxygen levels. hospitals tomonitorpatients’pulseand Pulse oximeters are commonly usedin health today? How dodoctors monitorour our quantityofsleep. (food energy) rate burned,heart andeven monitor distances walked orrun,calories Today wear fitnesstrackers we can to in thefuture? What willfitnesstrackers measure

A TIMELINE FOR MEASURING PULSE C.130–210 AD 1515–1559 / 1578–1657 blood circulation? What didRomans know about disease? How didRoman doctors diagnose How didtheydiscover this? about bloodcirculation? What diddoctors in1500sknow

1602–1609 1603 a pendulum? What didGalileonotice about measure hispatient’spulse? What didSantoriousetohelphim

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1924 / 1942

CURRENT health today? How dodoctors monitorour in thefuture? What willfitnesstrackers measure

MAKING A MODEL OF SANTORIO’S PULSILOGIUM band, andamarker bead (ormaskingtape/clay). 2m strong thread, aweight withaloop(modellingclay),anelastic You willneed:astripofcard (about1m),awooden beam/metre ruler, below thegroove. approximately 70cm The bobshouldhang pendulum. in thecard holdsthe pendulum end.Agroove wooden beamatthe The card overlaps the stop thethread slipping. band atoneendwill the beam.Arubber Lay thethread along beam. Chooseascale. thread halfwayalongthe Attach amarker tothe THE JOURNEY OF THE PULSE METER

We are going to learn about Santorio Santorio and how he compared people’s with a pulsilogium. We will be making a pulsilogium.

VOCABULARY PULSE SCALE PENDULUM RELIABILITY MEASUREMENT WHAT DID PEOPLE ALREADY KNOW?

Your heart pumps blood around You can feel your heart Your pulse can become faster/ your body in 2 loops. beat (pulse). slower when you are unwell. WHAT DID PEOPLE ALREADY KNOW?

No reliable clocks No electrical monitors

How did doctors measure pulse rate accurately in 16th century? WHAT DID THE SCIENTIST NOTICE?

Santorio knew: • That a swinging pendulum has a regular ‘beat’ • The time taken (period) for a pendulum to swing out and back depends upon the length of the string.

Your turn… How can you make a pendulum swing faster/slower? Hint: try changing the length of the pendulum. Have a go! WHAT QUESTION DID THE SCIENTIST ASK? WHAT QUESTION DID THE SCIENTIST ASK?

How can I change the length of the pendulum whilst it is in motion so that it matches the person’s pulse? WHAT DID THE SCIENTIST DO?

Santorio made a beam-type pulsilogium

How do you think Santorio changed the length of the pendulum? What do you think Santorio used to make this instrument? WHAT WILL YOU DO?

How can you change the period of the pendulum (time taken to swing back and forth) so it matches the pulse?

What will you need to change? What will you keep the same? WHAT WILL YOU DO?

1. Attach a ‘bob’ to a long 2. Attach a 1m strip of thick card to a beam/metre piece of thread (> 2m). ruler allowing the card to overlap at one end. A groove or a hole in the overlapped card holds the pendulum thread. Lay the thread along the beam so that the bob hangs approximately 70cm below the groove or hole. A rubber band at the other end of the beam will stop the thread slipping. Attach a marker to the thread half way along the beam.

3. Can you feel a person’s pulse? 4. Adjust the length of the pendulum thread so that the swing matches the person’s pulse. WHAT WILL YOU DO? Santorio’s diagrams do not show what scale he used on his beam so we do not know what units he used to ‘measure’ pulse.

Numbers? Emojis?

Musical vocabulary?

You need to choose a scale for your pulsilogium. Now you can record the patient’s pulse. WHAT DID THE SCIENTIST FIND OUT?

Santorio’s pulsilogium could detect very small changes in pulse. What did you find out?

Did you repeat your experiment? Was the patient Was the pulsilogium resting or active? Did you get the held the same way same readings? each time? Did the pendulum Why might you get swing in a straight line? different readings?

Was the pulse counted accurately? Were the pendulum swings counted accurately? Were the pulse and pendulum properly synchronised? WHAT DID THE SCIENTIST FIND OUT?

Santorio expressed pulse as ‘degrees’ on a numerical scale. He compared the patient’s current reading with an earlier one. The difference showed the direction and amount of change of speed of the pulse. What did you find out?

Which scale did Numerical scales Emoji scales mm or cm? you use? inches? Does the type of another? scale matter?

Musical scales Adagio – Allegro WHAT DID OTHER SCIENTISTS DO NEXT?

Nowadays we have accurate clocks. Any doctor anywhere can measure a patient’s pulse by counting the beats per minute. Oximeters measure the oxygen content of blood without needing to take a blood sample. They are routinely used in hospitals and clinics today for this purpose and to measure pulse. Electrocardiograms (ECG) are used today to detect heart (cardiac) problems. EGGs detect tiny electrical changes on the skin arising from the heart beating. WHAT ARE CURRENT SCIENTISTS DOING?

Dr Kat Dibb is studying the grooves in heart cells that spread the electrical pulse of a heartbeat. Heart failure can result in loss of these structures. This research could lead to the development of new treatments to prevent dangerous heart rhythms from occurring. WHAT WOULD YOU DO NEXT?

If you had a fitness tracker, what would you want it to measure?