Fill in the gaps with the correct words.

In today’s lecture we’re going to be talking about experiments, and I thought it might be interesting for you all 1. (1 p.) learn about the world’s oldest continuously running laboratory experiment 2. (1 p.) is still going today. In fact, it holds the Guinness World Record for 3. (1 p.) the longest-running experiment. This experiment began in 1927 and has been going 4. (1 p.) 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, 5. (1 p.) as pitch, can have quite surprising properties.

You see, when pitch is at room temperature, it feels solid. You can easily break it 6. (1 p.) a hammer. However, it isn’t in 7. (1 p.) 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 8. (1 p.) a glass funnel. He allowed the pitch to cool and settle – for three years. He then turned the funnel upside 9. (1 p.) and cut the top off it.

Since 10. (1 p.) , the pitch has slowly dropped out of the funnel. How slowly? Well, the first drop 11. (1 p.) eight years to fall. It took another forty years for 12. (1 p.) five drops to fall. Today it’s been almost 90 years since the experiment started. Only nine drops 13. (1 p.) fallen from the funnel. The last drop fell in April 2014 and the next one is expected to fall in 14. (1 p.) 2020s.

The experiment has 15. (1 p.) tragic story associated with it. Professor Parnell died 16. (1 p.) 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 17. (1 p.) 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 18. (1 p.) time the pitch dropped.

The pitch drop experiment is something we can all participate 19. (1 p.) 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 20. (1 p.) in Dublin, and the video of the moment the pitch actually dropped went viral on the internet.