A lecture about an experiment

A lecture about an experiment

Listen to the lecture about a science experiment to practise and improve your listening skills.

Do the preparation task first. Then listen to the audio and do the exercises.


In today's lecture we're going to be talking about experiments, and I thought it might be interesting for you all to learn about the world's oldest continuously running laboratory experiment that is still going today. In fact, it holds the Guinness World Record for being the longest-running experiment. This experiment began in 1927 and has been going ever since.

It's called the 'pitch drop' experiment and it was created by Professor Thomas Parnell at the University of Queensland, Australia. Parnell was the university's first physics professor, and he wanted to show in this experiment that everyday materials, such as pitch, can have quite surprising properties.

You see, when pitch is at room temperature, it feels solid. You can easily break it with a hammer. However, it isn't in fact solid. At room temperature, pitch is many billions of times more viscous than water, but it's actually fluid.

In 1927, Professor Parnell took a sample of pitch. He heated it and poured it into a glass funnel. He allowed the pitch to cool and settle – for three years. He then turned the funnel upside down and cut the top off it.

Since then, the pitch has slowly dropped out of the funnel. How slowly? Well, the first drop took eight years to fall. It took another forty years for another five drops to fall. Today it's been almost 90 years since the experiment started. Only nine drops have fallen from the funnel. The last drop fell in April 2014 and the next one is expected to fall in the 2020s.

The experiment has a tragic story associated with it. Professor Parnell died without seeing a pitch drop. His replacement, Professor John Mainstone, became responsible for the pitch drop experiment from 1961. He held the job for 52 years, and missed seeing the drop fall three times – by a day in 1977, by just five minutes in 1988 and finally in 2000, when the webcam that was recording the experiment suffered a power outage for 20 minutes, during which time the pitch dropped.

The pitch drop experiment is something we can all participate in now. There's a live web stream that allows anyone to watch the glass funnel and wait for the fateful moment. A similar experiment to the Queensland pitch drop was set up in Dublin, and the video of the moment the pitch actually dropped went viral on the internet. It's interesting to see how a very slow event can spread news so quickly.

Task 1

Task 2


Worksheet79.41 KB

Language level

Average: 4 (78 votes)
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Profile picture for user Kirk Moore

Submitted by Kirk Moore on Mon, 08/07/2019 - 11:25

In reply to by Ola Jamal


Hello Ola Jamal

There isn't so much a difference of meaning as there is a different perspective on the future event. The first one, which is in the future continuous, uses the continuous aspect, which can express many different ideas. I'd have to know more about the context to say what it means here, but it could express that it's what the speaker expects, for example. The other one expresses more of an intention. The same person might use both of these sentences; which one you use often depends on how you imagine the future event.

Hope this helps.

All the best


The LearnEnglish Team

Submitted by Evgeny N on Tue, 11/06/2019 - 16:29

Interesting story and very good exercises. Thank you very much for them!

Submitted by Shuferu on Wed, 15/05/2019 - 15:56

thank I enjoyed the story

Submitted by Ken Moore on Mon, 08/04/2019 - 17:24

A good article. I would suggest that glass is in fact a more viscous material than pitch.

Submitted by Mahidul Islam on Mon, 08/04/2019 - 16:18

nice experience ! I enjoyed the story and also the process of self assessment. Thank you
Profile picture for user Jazz12345678

Submitted by Jazz12345678 on Thu, 04/04/2019 - 14:30

So perfectionist I answered it all right but you marked it wrong