Category Archives: Climate science

The man who named the clouds

Assistant Curator Rachel Boon looks at the pioneering work of Luke Howard, who died 150 years ago today.

Stare up the sky and what can you see hiding amongst the clouds?  Mythical creatures perhaps or maybe you neighbour’s dog chasing a ball. Spotting shapes in the sky is fun, especially on a sunny day. The amateur meteorologist Luke Howard looked up and classified these wisps of white, changing the course of meteorology forever. 

Luke Howard had been inspired by nature from a young age. Born in London in 1772 Howard developed his childhood passion and became an amateur meteorologist. He even built a laboratory at his home filled with instruments to analyse the weather. Even though his day job was manufacturing chemicals for the pharmaceutical industry, Howard’s scientific work changed the way we understand the climate around us.

Luke Howard blue plaque. Credit: Wikipedia/Acabashi

Luke Howard blue plaque. Credit: Wikipedia/Acabashi

Before the 19th century, many meteorologists thought of each cloud as unique, unclassifiable and in a state of temporary existence. Instead of strict descriptions clouds were recorded by colour or individual interpretation. This all changed when Howard presented his Essay on the Modification of Clouds to the Askesian Society in 1802. The impact of this work was immense, elevating the natural phenomenon to the realms of worthy scientific investigation. Founded in detailed observations, with a pinch of imagination, these cloud types were; cumulus, Latin for ‘heap’; stratus, Latin for ‘layer’, and cirrus, Latin for ‘curl of hair’. Words we still use today.

Luke Howard captured these transient phenomena in delicate, though scientifically scrutinised sketches. The Science Museum has a rich collection of these images in a range of medium from pencil to watercolours, with some on display in our Making the Modern World gallery. It has been argued by historians of art and science that Howard’s contemporary John Constable was influenced by this new meteorological theory and visible in his powerful landscapes. Not only did Howard’s images inspire great art but so did his published essays which stimulated the imaginations of the poets Johann Wolfgang von Goethe and Percy Shelly.

Watercolour sketch by Edward Kennion with cloud studies by Luke Howard c 1808-1811

Watercolour sketch by Edward Kennion with cloud studies by Luke Howard, c 1808-1811. Image credit: Science Museum / SSPL

Even though Luke Howard was only an amateur meteorologist he believed strongly that developments in science depended on accurate data gathering. By taking daily observations of temperature, rainfall, atmospheric pressure and wind direction from his home in Tottenham, Howard became one of the first pioneers of urban climate studies. He published the first two volumes of The Climate of London deduced from Meteorological Observations at different places in the Neighbourhood of the Metropolis in 1818 and 1820, followed by an extensive second edition in 1833. Howard noted the changes in weather religiously for over 30 years recording his results in tables and innovative graphics.

You can learn more about Luke Howard’s instruments in the Science in the 18th Century gallery as part of the Climate Changing Stories display.

Curatorial collecting – new radioactive tracer machine

One of the best parts of a curator’s job is collecting new objects. It can sometimes feel like a daunting task but occasionally serendipitous circumstances lead to a great acquisition.

A member of staff from GE Healthcare was visiting the Science and Art of Medicine gallery of the 5th floor of the museum and noticed that their company had recently developed a new updated version of a piece of kit. Fortunately for us, they offered us a model for the Museum’s collections.

Model of a Technetium-99 generator by GE Healthcare

Model of a Technetium-99 generator by GE Healthcare (© GE Healthcare)

The generator produces a radioactive version of the element Technetium-99, used as a tracer in the body. Radioactive tracers are used in nuclear medicine. This is the use of radioactive isotopes to diagnose and treat illness. The radioactive element is injected, swallowed or inhaled and the progress is tracked using a gamma camera or a PET scanner. The radiation received from a tracer is comparable to that of an X-ray.

PET Scanner ( Wellcome Images )

Non-radioactive tracers have also been used to image the body. Early versions of tracers include a barium meal drink used with X-rays to show up the guts.

Barium 'Shadow Meal', 1981-595/1 (Science Museum, London)

One of the most commonly used tracers is Technetium-99. One of the problems is that Technetium-99 has a half-life of only 6 hours. So it is transported with a longer lasting isotope Molybdenum-99. Once at the hospital, the isotopes can be separated. This is done by injecting a saline or salt solution which leaves the molybdenum absorbed on the aluminium columns inside.

The designers at GE Healthcare worked in collaboration with hospital staff including radiographers to find out their needs and come up with a design solution. The model has won design awards from the Design Business Association and has also reduced its carbon footprint in the process.

No Laughing Matter

A Scientific Lecture, 1802

Gilray's 'A Scientific Lecture', 1802, depicts Humphry Davy 'bellowing' laughing gas

What have Humphry Davy, Mike Melvill and my dentist got in common? Answer: They’ve all exploited the chemistry of nitrous oxide, popularly known as ‘laughing gas’.

Davy experimented with euphoria-inducing properties of the gas with his friends Samuel Taylor Coleridge and James Watt. Davy was working at the Pneumatic Institution, set up by Thomas Beddoes to investigate the medical properties of inhaled or ‘factitous airs’. Davy pursued his experiments – part scientific, part recreational – with his normal con brio and was fortunate not to have seriously damaged his and others’ health.

Lucy Baldwin's Analgesic Apparatus, 1955-80

Lucy Baldwin's Analgesic Apparatus, 1955-80, mixed oxygen and nitrous oxide during midwifery (Science Museum/Science & Society)

My dentist, alongside doctors and medics, has long employed nitrous oxide as an analgesic, to relax patients and as a prelude to anaesthesia.

And Mike Melvill? Well, as pilot of SpaceShipOne, the world’s first privately developed spacecraft, he depended on its ability to oxidise rocket fuel for the thrust that carried him spaceward on his pioneering sub-orbital flight of 2004.

Dobson Ozone spectrometer, 1926

Dobson Ozone spectrometer, 1926. Dobson's technique for detecting ozone led to the discovery of the ozone hole over Antartica in 1985. (Science Museum/Science & Society)

So nitrous oxide has a variety of uses but it also has a dark side. Whether produced naturally or by industrial activity it leads to ozone depletion of the upper atmosphere. This lets in more of the Sun’s harmful ultra-violet radiation which the ozone molecules normally absorb. Plus, nitrous oxide acts as a particularly effective greenhouse gas, trapping the heat re-radiated from the Earth’s surface and causing global temperature rises.

No laughing matter indeed.