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.

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Language level

Yes, I know a experiment it's about Newtown gravity experiment. When an apple falling from a tree there is a gravity.

Yes I know other famous experiments, one is about earth gravity famous experiment of Newton through an apple. The other famous experiment is about the Invention of the telephone by Graham Bell.
Hello, I have a question, I'm sorry if it is not related with the topic, it is about these two sentences: 1) We can either make an omelette or pancake 2) She can play either the guitar or the dumb at the concert. As you can see, there's a different position for the word "either" in these sentences. In the first one "either" is located between the modal verb "can" and the verb "make" and in the second one "either" is located after the verb "play". Can I use those two structures if I want to a do sentence with a modal verb or auxiliary verb and a common verb or is there any difference between those structures? Thank you

Hello GiulianaAndy,

In these examples the position of either makes no difference. The action (play/make) remains the same and the instrument/dish is the option.


It's possible to use either to show a choice between actions. In this case either must come before the verb:

She can either play the guitar or sing a song.



The LearnEnglish Team

Yes, I do. I actually know one famous experiment, well a psychological experiment, it was execute in 1961. The general setup of this experiment was that the subject who has been assured payment would be told by an authority figure called the experimenter to give an electric shock punishment to a student when a wrong answer is given. The subject is aware that each wrong answer would have a progressively increased voltage. What the subject doesn't know is that there is no electrical shock, the student is an actor, and the administrator is following a script. It was found that despite the voltage getting to fatal levels with some simple prodding from the administrator around 2-3 of the subject continued pressing that bottom even when the student would scream and beg for mercy. It demonstrates that the majority of these subjects have the "accomplishment" to become party to monstrous acts with the imperative of obeying authority annulling a personal sense of ethic.
I'm sorry, but for some unknown reason my comments are being erased. Am I asking off topic ? I am just interested, why in the first sentence of the preparation task isn't used "was" before "given" ? ("Pitch is the name given to a black substance ..." vs "Pitch is the name was given to a black substance..." Will it be incorrect If I use "was" ?
Hello, Could explain to me, why in the preparation task, in the first sentence, you didn't use "was" ? (Pitch is the name given to a black substance..... Pitch is the name was given to a black substance .....) Thanks a lot for your feedback

Hello lean,

This is an example of a reduced relative clause. The full wording of this is 'Pitch is the name that is given to a black substance ...' We often remove the relative pronoun ('that') and auxiliary verb 'is') in speaking and writing. 

It is possible to say 'was given' instead of 'is given', but since people still use the word 'pitch' this way, the present simple makes more sense.

Don't worry, we haven't been deleting your comments. It's just that we check all comments before they are published, which means that it can take some hours for them to appear on the site, especially on the weekends when we don't check them quite as often.

All the best,


The LearnEnglish Team

I had study about Newton's experiment. He saw a apple falling from a tree then he asked himself why is a apple falling from tree. He invented gravity law.
I know the experiments done by Marie Curie and I think are wonderful. She and her hasband did many developments about radiactivity and found out two elements and they helped to development of the medicine advance en the fields like cancer treatment and radiology.
I know one. Actually it is not as scientific as the pitch drop thing, but it has a deeper meaning to mass production and the quality of goods produced. Have you heard of the light bulb invented by Thomas Edison? Yes, the forefather of all obsolete lightbulbs that only last 1000 hrs. There is a centennial light still burning at Livermore Fire Station No 6 in California. And it was lit in 1901. This bulb however is not quite exactly, what Edison came up with, but the manufacturing was patented by a French engineer.
Among the most famous scientific experiments I remember the one of Guglielmo Marconi. He wasn't a scientist with an academic curriculum vitae. but an inventor and an entrepreneur. Eighteen ninety-five Marconi fulfilled his famous experiment: the transmission of a signal at a distance via radio waves.
I know about an experiment testing the broken windows theory. The testing was running by Philippe Zimbardo in 1969. He parked a car with no license plates and the hood up in the Bronx New York (a worker class neighborhood) and another one in Palo Alto California (a high class place). The Bronx’s car was completely vandalized in 24 hours. At the same time, the Palo Alto’s vehicle remained untouched after a week until Zimbardo himself broke a window with a hammer. Afterwards, the car was vandalized too. The conclusion: social apathy leads to a decrease in the sense of mutual regard and obligations of civility.
When I was coursing Physics at the university, I knew about the Focault Experiment, I was very surprised by this impressive experiment, this helped to demonstrate the rotation of earth many years ago.
Yes I listened there was something like an psychological experiment called “Rhythm”. In summary, it was about a woman in a room who put different things on a table, from bread to a gun, then she invited some people to came in and closed the door. For many hours she just stand without make a noise and the more hours passed the more aggressive people became. Its a little creepy but its interesting.
It is a hard topic, if we had on the experiment, we couldn't image what happen. Fortunately, I had it when I was in elementary school. But I can't remember clearly because the school hadn't enough condition for us to practise full time. With a few hours were impressed my memories. Moreover, practise experiment are made everybody to understand long time and be aware of the theme.
My first experiment was the dissection of the frog. Catching a frog is a very difficult task somehow I managed to catch it. I took the frog in the laboratory, dissected from the middle. I observed that the internal organs and system of the frog is very similar to humans.
I never heard about that experiment when I was studing at different Uni in queensland state. On my opinion, first few years it looked like really intresting experiment but time goes by it is more be like a guinness world record than scientific experiment. Because Dr Parnell already got his result (pitch is liquid)and there is nothing to wait new result or changes anymore. Only interesting thing is it has going long time thats it.
I recalled an experiment about the human moral or psychology. There was a crazy train losing control when you were in the driving room and you could decide which direction to turn the steering wheel. Ouside the train, there were 5 people in the right track and 1 person in the left. Which side will you choose to turn the steering wheel?
I found the tasks of this listening very useful, I´m looking forward to finding this kind of activities in the following listenings. According to the question above, I know a few psychological experiments. One of them is called The Stanford prison experiment. In summary, it´s about how the behaviour of a person changes depending on the role that he or she is playing. You can look it up for further information, it´s really interesting. Cheers from Madrid.
I remember the element radium that discovered by Madame Curie. The downsides were also great. Marie's work with radioactive elements inflicted serious burns to her arms and hands. She devoted all her time to the study of radium.
The Michelson-Morley experiment. The main objective of this experiment was to detect the luminiferous ether which was believed to be the medium wherein light and other electromagnetic waves propagate. In this experiment, they measured the speed of light in many different angles and speculated that they should measure a maximum and a minimum value for the speed of light. The maximum value of the speed of light will be measured when the light is travelling within the ether, and the minimum value can be measured when the light is travelling against the motion of the ether. However, no differences in the speed of light was detected which suggested that the light does not require any medium to propagate onto. This experiment is now known as the "Best failure in science" because it is being used in a lot of practical applications specially in laboratory testings.
No I don't know a lot about any experiments, at the beginning I get the point of the experiment and I think that it's an interesting fact and we have learned something new which is great, but now this experiment is just marketing for the university I can't believe that there are people watching constantly a stream waiting for a drop.
I really surprised that it has been taken eight years for the first drop. I would say then the pitch drop is almost an oil substance if it could be solid but actually is a fluid. In fact, oil can be frozen at room temperature too for example oil from cotton, when you want to save oil of cotton in bottle, you can pour the warm oil into the bottle, and it can be secured in a dark room for many years. Over time, the oil will become a solid shape, but in fact, it was fluid. You can also turn the bottle upside down and cut the top off it. It is only my prediction, in school time I loved to learn physic...:) so I am saying this process.
No :/. Actually I haven’t been studying that much For the past four years so I don’t know many things related with experiments or things like that but I’m glad to read this article it’s really interesting. It’s weird to think of bitumen as a solid property. Thank you for the lesson anyway ❤️
Of course, I've read or heard about many different experiments. Some of them are very interesting but some are completely stupid (in my humble opinion) and caused a meme about the "Britain scientists". But, telling the truth I'm not the person who interested in any kind of experiments that much to keep them in mind. So it's a bit hard for me to give a proper answer to this question. In his case, let me say some words about the "Pitch drop experiment". I think it was quite interesting in 1927 to start this experiment - to show others that the common material which everybody took like something solid turn out to be liquid. And the very first drop (maybe the first two or three) was a great achievement for all who took part in this experiment. But now, all this "drops waiting" through the years looks like something stupid and absolutely senseless. This experiment evolved into the university tradition and doesn't belong to science anymore. Of course, it's only my opinion and I admit someone can think differently.
Dear team. From the lesson above. Pitch is (BLACK SUBSTANCE) a thick, black substance that was used in the past to make wooden ships and buildings waterproof. The question: Is definition right in that context??? What's the urgency of picth drop in our live??? I think it's just waste our time to see it. Thank you very much for your explanation and answer.

Hello fahri,

Yes, that's correct. Pitch is an extremely thick liquid - so thick it appears to be a solid - and that is why it drips so slowly.



The LearnEnglish Team

I don’t understand The experiment has a tragic story associated with it. Professor Parnell died without seeing a pitch drop.

Hello nona nasr,

Professor Parnell set the experiment up and it would have been nice if he had seen the pitch drop, but unfortunately he did not. This is why the story has a sad (tragic) side.



The LearnEnglish Team

I've got a question. The thing is that the instructions of the second task are asking for an answer with one or three words, nevertheless one of the answers is a word and a NUMBER. Shouldn't it be a good idea to say "Complete the sentences with one to three words or/and numbers?
Yes, i know. The most well-known experment at biology is Mendel's experiment on peas plants in1800s.
Yes. They includes colour mixtures, mixtures of solution, solar, sunlight in plant growth and so on.
Yes, I gues the most famous experiment I know is The Laika's launch, when Sovietics sent a dog into a space mission becuse they wanted to test if the space travels are safety for humans. The dog would never come back, it was a suicide mission and it is really shocking to me.
Will Iam not familiar with the experiments that are happening ,but i look forward to read more about them .
Hello everyone!! well I'd hear about experiments with atomic particles moving in circles at incredible speed, what they are trying to do is create new energy frome that particle movement.
this really an ausome thing which i have never met with this type of a think which is interesting biggggg!!!!!!! fan now on words 4 ur course
I have completed A Lecture About Experiment. The level I chose was Upper Intermediate B2.
i think i have read about big car industry companies (like tessla & wolex) testing their auto-driving cars in roads.they have lunched the test a few years ago and those cars have passed long distances through highways in america without any problem.
Do you know of any other famous experiments? What are they? Current famous experiments are the Elon Musk's Neurolink to integrate an eletronic chip into our brain to boost its creative thinking, data processing and many other capabilities of the brain. It sounds to me like a Johnny Memonic The Keanu Reeves Old Sci-Fi Movie, but I hope this will work harmlessly with our Bio Organ Structured Brain. Another one so far is the Uber's Driverless Cars experiment and that is now nearly a success without any casualties. Another exiciting news is the Japanese's Flying Car Experiment and it is now successful. But will take some time to bring for our everday use with low cost.
Hi, Could you please explain, why the sentence "He never saw the pitch drop" about Professor John Mainstone is true? Thank you in advance. Regards, Adam