On this day in science history: the first X-rays were observed

In 1895, Wilhelm Röntgen first observed X-rays during an experiment at Würzburg University. After further investigation, on 1 Jan 1896, he notified other scientists of his discovery of this new radiation that would become known as X-rays. He sent copies of his manuscript and some of his X-ray photographs to several renowned physicists and friends, including Lord Kelvin in Glasgow and in Paris. On 5 Jan 1896, Die Presse published the news in a front-page article which described his investigations and suggested new methods of medical diagnoses might be made with this new kind of radiation.

Wilhelm Röntgen, by Nobel foundation [Public domain or Public domain], via Wikimedia Commons

So, what are the properties of X-Rays? 

X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds. This makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a short period of time causes radiation sickness, while lower doses can give an increased risk of radiation-induced cancer. In medical imaging this increased cancer risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in cancer treatment to kill malignant cells using radiation therapy. It is also used for material characterization using X-ray spectroscopy.

Hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects. The most often seen applications are in medical radiography and airport security scanners, but similar techniques are also important in industry (e.g. industrial radiography and industrial CT scanning) and research (e.g. small animal CT). The penetration depth varies with several orders of magnitude over the X-ray spectrum. This allows the photon energy to be adjusted for the application so as to give sufficient transmission through the object and at the same time good contrast in the image.

X-rays have much shorter wavelength than visible light, which makes it possible to probe structures much smaller than what can be seen using a normal microscope. This can be used in X-ray microscopy to acquire high resolution images, but also in X-ray crystallography to determine the positions of atoms in crystals.

For more information, visit:-

http://www.todayinsci.com/11/11_08.htm

https://en.wikipedia.org/wiki/X-ray

http://www.prlabs.co.uk/lab-supplies.php?N=radiationradioactive-waste-bag-clear-1&Id=2725

Ancient air pockets changing the history of Earth’s oxygen

Ancient air trapped in rock salt for 813 million years is changing the timeline of atmospheric changes and life on Earth.

Defining past atmospheric compositions is an important yet daunting task for geologists. Most methods for determining past Earth surface conditions rely on indirect proxies gleaned from ancient sedimentary rocks. Further complicating matters, sedimentary rocks are notoriously difficult to date because they contain remnants of other rocks formed at various times.

As a result, oxygenation, or the rise of oxygen in the Earth's atmosphere, has been presumed to occur about 550 million years ago near the boundary between the Precambrian and Paleozoic geologic periods.

The Earth seeen from Apollo 17. By NASA/Apollo 17 crew; taken by either Harrison Schmitt or Ron Evans [Public domain or Public domain], via Wikimedia Commons

West Virginia University geologist Kathleen Benison is part of a research team using new direct methods to measure the Earth's oxygenation.

The team's study identifies, for the first time, exactly how much oxygen was in Earth's atmosphere 813 million years ago - 10.9 percent. This finding, they say, demonstrates that oxygenation on Earth occurred 300 million years earlier than previously concluded from indirect measurements.

"Diversity of life emerges right around this time period," Benison said. "We used to think that to have diversity of life we needed specific things, including a certain amount of oxygen. (The findings) show that not as much oxygen is required for organisms to develop."

Fluid inclusions, the microscopic bubbles of liquids and gases in rock salt, can contain trapped air. Analysis of this trapped air allows researchers to understand past surface conditions and how oxygen has changed over the course of geologic history.

The team used a quadrupole mass spectrometer to study the air pockets. Carefully crushing minute rock salt crystals released water and gases into the mass spectrometer, which then analyzed for various compounds of oxygen and other gases.

"There are a lot of different environmental conditions specific from the past that we can find occurring in modern samples," Benison said. "This tells us about the range of conditions on Earth and also has implications for Mars."

For more information visit:

https://www.sciencedaily.com/releases/2016/08/160822174234.htm

http://www.prlabs.co.uk/lab-supplies.php?N=oxygen-sensor&Id=75102

Copper Sulphate

Copper (II) sulfate, also known as cupric sulfate or copper sulphate, is the chemical compound with the chemical formula CuSO4. This salt exists as a series of compounds that differ in their degree of hydration. The anhydrous form is a pale green or grey-white powder, whereas the pentahydrate (CuSO4·5H2O), the most commonly encountered salt, is bright blue.

Copper Sulphate Crystals

Copper sulphate is normally produced industrially by treating copper metal with hot concentrated sulphuric acid.  Laboratories generally purchase their own - eg here.

At 650 °C (1,202 °F), copper (II) sulphate decomposes into copper (II) oxide (CuO) and sulphur trioxide (SO₃).  Its blue colour is due to water of hydration. When heated in an open flame the crystals are dehydrated and turn greyish-white.
 

Copper sulphate pentahydrate is a fungicide.  Mixed with lime it is called Bordeaux mixture and used to control fungus on grapes, melons, and other berries.  Its use as a herbicide is not agricultural, but instead for control of invasive aquatic plants and the roots of plants near pipes containing water. It is used in swimming pools as an algicide. A dilute solution of copper sulphate is used to treat aquarium fish for parasitic infections.

 

Several chemical tests utilize copper sulphate. It is used in Fehling's solution and Benedict's solution to test for reducing sugars, which reduce the soluble blue copper(II) sulphate to insoluble red copper(I) oxide. Copper(II) sulphate is also used in the Biuret reagent to test for proteins.

Copper sulphate is a commonly included chemical in children's chemistry sets and is often used to grow crystals as can be seen here.

The chemical is also used in flame tests - again which can be seen here.

In 2008, the artist Roger Hiorns filled an abandoned waterproofed council flat in London with 75,000 litres of copper sulphate solution. The solution was left to crystallize for several weeks before the flat was drained, leaving crystal-covered walls, floors and ceilings. The work is titled Seizure.

For more information visit:-
http://en.wikipedia.org/wiki/Copper(II)_sulphate
http://prlabpak.blogspot.co.uk/2014/09/flamin-hot-colours.html
http://prlabpak.blogspot.co.uk/2012/09/making-chemical-garden.html