Volcanoes: Melting The Earth - James Jackson's 1995 Christmas Lectures 3/5
In his third lecture, James Jackson talks about volcanoes.Watch all the lectures in this series here: https://youtube.com/playlist?list=PLbnrZHfNEDZzN4JcqnWDW02rO0gJU7qBx&si=lmo1ZuOBkecGK5Rq
Watch our newest Christmas lectures here: https://www.youtube.com/playlist?list=PLbnrZHfNEDZyQJZLPMjwEoOLdkFBLU2m1
This was recorded on 3 Dec 1995.
--
2025 and 2026 mark 200 years of the Royal Institution Christmas Lectures — a world famous series showcasing science, curiosity, and mind-blowing demos, and started by the legendary Michael Faraday himself. To celebrate, we're unlocking the archive. Every week, we’ll upload a classic lecture to our YouTube channel — some not seen since they aired on TV. Sign up as a Science Supporter and get early access here: https://www.youtube.com/channel/UCYeF244yNGuFefuFKqxIAXw/join
--
From the 1995 programme notes:
Volcanoes are among the most dramatic features of the Earth, and a sure sign that the planet is alive. But what we see on land is only a small part of the story; far more is going on out of sight underwater.
In the middle of the oceans about twenty cubic kilometres of liquid rock is added to the seafloor every year to make new plates. This activity poses a major paradox. We know that the outer part of the Earth is solid because it rings like a bell in earthquakes. How, then, is it able to produce such quantities of molten rock?
Most volcanoes are located near the boundaries between the plates that cover the Earth, and the type of boundary provides a clue to what is going on. With submersible ships we can travel to where plates are created at mid-ocean ridges, where we find a seafloor belching clouds of superheated black water from chimneys — yet this dark, apparently inhospitable world is alive with creatures that never see the sun.
The runny magma that pours from the Earth where plates separate can flow huge distances on land and make spectacular displays of fountains and bubbling cauldrons of liquid rock. By contrast, the magma produced where plates converge is often much stickier and hardly flows at all; instead, it erupts in catastrophic explosions. Why should these magmas be so different?
Some volcanoes occur away from plate boundaries, at hot spots that occur above rising currents in the hot creeping rock that circulates beneath the plates. They are a useful reminder that the plates at the surface are only part of the story, and that much is hidden below. Occasionally a rising current below coincides with plate separation at the surface. The Earth can then produce fantastic quantities of lava, enough to bury whole continents to depths of a kilometre or two, with devastating effects for the environment and climate.
--
About the 1995 CHRISTMAS LECTURES
Catastrophes such as volcanic eruptions, earthquakes, climate change and sea level rise are starting to have a huge impact on our lives as our population increases and we colonise every available corner of the world, particularly the coastlines. Yet at the same time these phenomena, which are disasters to us, are a natural part of the way the Earth behaves.
We can use them as tools to see deep inside the Earth, to see how the planet is put together, and how it changes with time. Scientists used to see the Earth as a planet whose surface had been the victim of random and unexplained events, such as mountain building and changing climate. Now we know that what we see at the surface is caused by vigorous motions deep inside the Earth — motions that are slow compared with our lifetimes, but are very fast compared with the life of the Earth itself. Far from living on a dead lump of rock in Space, we are living on jelly, but didn't realise it! These lectures trace the story of how and why our views changed — from a fumbling suspicion that continents had moved around, through a detailed reconstruction of how the pieces fit together, to the present, where we can measure the motions directly and see them going on.
Find out more about the CHRISTMAS LECTURES here: https://www.rigb.org/christmas-lectures
---
Join this channel to get access to perks:
https://www.youtube.com/channel/UCYeF244yNGuFefuFKqxIAXw/join
Subscribe for regular science videos: http://bit.ly/RiSubscRibe
The Ri is on Twitter: http://twitter.com/ri_science
and Facebook: http://www.facebook.com/royalinstitution
and TikTok: https://www.tiktok.com/@ri_science
Listen to the Ri podcast: https://podcasters.spotify.com/pod/show/ri-science-podcast
Donate to the RI and help us bring you more lectures: https://www.rigb.org/support-us/donate-ri
Our editorial policy: https://www.rigb.org/editing-ri-talks-and-moderating-comments
Subscribe for the latest science videos: http://bit.ly/RiNewsletter
Product links on this page may be affiliate links which means it won't cost you any extra but we may earn a small commission if you decide to purchase through the link. Receive SMS online on sms24.me
TubeReader video aggregator is a website that collects and organizes online videos from the YouTube source. Video aggregation is done for different purposes, and TubeReader take different approaches to achieve their purpose.
Our try to collect videos of high quality or interest for visitors to view; the collection may be made by editors or may be based on community votes.
Another method is to base the collection on those videos most viewed, either at the aggregator site or at various popular video hosting sites.
TubeReader site exists to allow users to collect their own sets of videos, for personal use as well as for browsing and viewing by others; TubeReader can develop online communities around video sharing.
Our site allow users to create a personalized video playlist, for personal use as well as for browsing and viewing by others.
@YouTubeReaderBot allows you to subscribe to Youtube channels.
By using @YouTubeReaderBot Bot you agree with YouTube Terms of Service.
Use the @YouTubeReaderBot telegram bot to be the first to be notified when new videos are released on your favorite channels.
Look for new videos or channels and share them with your friends.
You can start using our bot from this video, subscribe now to Volcanoes: Melting The Earth - James Jackson's 1995 Christmas Lectures 3/5
What is YouTube?
YouTube is a free video sharing website that makes it easy to watch online videos. You can even create and upload your own videos to share with others. Originally created in 2005, YouTube is now one of the most popular sites on the Web, with visitors watching around 6 billion hours of video every month.
