Isotopes in Medicine and Industry. A complete list.

Here’s just a sampling of radioactive materials…and the many ways they improve lives.

Americium -241: Used in many smoke detectors for homes and business…to measure levels of toxic lead in dried paint samples…to ensure uniform thickness in rolling processes like paper production…and to help determine where oil wells should be drilled.

Cadmium -109: Used to analyse metal alloys for checking stock, sorting scrap.

Calcium – 47: Important aid to biomedical researchers studying the cell function and bone formation of mammals.

Californium – 252: Used to inspect airline luggage for hidden explosives…to gauge the moisture content of soil in the road construction and building industries…and to measure the moisture of materials stored in silos.

Carbon – 14: Helps in research to ensure that potential new drugs are metabolised without forming harmful by-products. Dating of artefacts up to 25,000 years old – see post and link to the Turin Shroud.

Caesium – 137: Used to treat cancers…to measure correct patient dosages of radioactive pharmaceuticals…to measure and control the liquid flow in oil pipelines…to tell researchers whether oil wells are plugged by sand…and to ensure the right fill level for packages of food, drugs and other products. (The products in these packages do not become radioactive.)

Chromium – 51: Used in research in red blood cell survival studies.

Cobalt – 57: Used in nuclear medicine to help physicians interpret diagnosis scans of patients’ organs, and to diagnose pernicious anemia.

Cobalt – 60 : Used to sterilize surgical instruments…to improve the safety and reliability of industrial fuel oil burners…and to preserve poultry fruits and spices.

Copper – 67: When injected with monoclonal antibodies into a cancer patient, helps the antibodies bind to and destroy the tumour.

Curium – 244: Used in mining to analyse material excavated from pits slurries from drilling operations.

Iodine – 123: Widely used to diagnose thyroid disorders.

Iodine – 129: Used to check some radioactivity counters in in vitro diagnostic testing laboratories.

Iodine – 131: Used to diagnose and treat thyroid disorders. (Former President George Bush and Mrs. Bush were both successfully treated for Graves’ disease, a thyroid disease, with radioactive iodine.)

Iridium – 192: Used to test the integrity of pipeline welds, boilers and aircraft parts.

Iron – 55: Used to analyse electroplating solutions.

Krypton – 85: Used in indicator lights in appliances like clothes washer and dryers, stereos and coffee makers…to gauge the thickness of thin plastics and sheet metal, rubber, textiles and paper…and to measure dust and pollutant levels.

Nickel – 63: Used to detect explosives…and as voltage regulators and current surge protectors in electronic devices.

Phosphorus – 32: Used in molecular biology and genetics research.

Plutonium – 238: Has safely and successfully powered over twenty NASA spacecraft since 1972.

Polonium – 210: Reduces the static charge in production of photographic film and phonograph records.

Promethium – 147: Used in electric blanket thermostats…and to gauge the thickness of thin plastics, thin sheet metal, rubber, textiles, and paper.

Radium – 226: Makes lightning rods more effective.

Selenium – 75: Used in protein studies in life science research.

Sodium – 24: Used to locate leaks in industrial pipelines…and in oil well studies.

Strontium – 85: Used to study bone formation and metabolism.

Technetium – 99m: The most widely used radioactive isotope for diagnostic studies in nuclear medicine. Different chemical forms are used for brain, bone, liver, spleen and kidney imaging and also for blood flow studies. M = metastable

Thallium – 204: Measures the dust and pollutant levels on filter paper…and gauges the thickness of plastics, sheet metal, rubber, textiles and paper.

Thoriated tungsten: Used in electric are welding rods in the construction, aircraft, petrochemical and food processing equipment industries. It produces easier starting, greater arc stability and less metal contamination.

Thorium – 229: Helps fluorescent lights to last longer.

Thorium – 230: Provides coloring and fluorescence in colored glazes and glassware.

Tritium: Used for life science and drug metabolism studies to ensure the safety of potential new drugs… for self-luminous aircraft and commercial exit signs… for luminous dials, gauges and wrist watches…and to produce luminous paint.

Uranium – 234: Used in dental fixtures like crowns and dentures to provide a natural color and brightness.

Uranium – 235: Fuel for nuclear power plants and naval nuclear propulsion systems…also used to produce fluorescent glassware, a variety of coloured glazes and wall tiles.

Xenon – 133: Used in nuclear medicine for lung ventilation and blood flow studies.

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The Rock Cycle

What goes around, comes around.

Rocks are constantly being recycled. To  recycle means to take something old and change it into something new. So, some old rocks that have been around for more than four billion years are being changed into different, newer rocks. Of course, that doesn’t happen overnight. It takes millions of years. To better understand how this happens, let’s take a journey through the rock cycle.

We begin with a volcano. There are lots of active volcanoes on the Earth – in times past there were probably a lot more than there are now.

We start in the mantle, in a place where the Earth’s crust is quite thin. Red hot magma is being pushed up towards the crust, which breaks open, and we have a volcano. Granite is Intrusive - it isn't formed from overflowing lavaSome of this magma creeps into the cracks of the volcano, cools and forms rocks such as coarse grained granite (right) while, the rest is forced out of the top. When the magma spews out of the volcano, it is called lava. The lava cools and forms igneous rocks such as basalt (left). (Ignis is Latin for ‘fire’)Basalt is formed on the surface - Extrusive igneous rock

Some of the igneous rock rolls very slowly down the mountains formed by the volcanoes, helped down by rainwater and eventually ends up in the ocean. As they roll, bits and pieces of the igneous rocks are broken down and form sediments. Layer after layer of sediments are pressed down and cemented together forming sedimentary rocks. This is Jurassic sandstone, a sedimentary rock on its way to the sea, from Utah, in the USA. Look at the layering which indicates a geological event.Layered Sandstone

Some of the sedimentary rocks on the very bottom get hot because of the pressure. This heat and pressure changes the rock, interacting with water and minerals to form metamorphic rock.  When the metamorphic rock is buried deeper, it gets hotter and melts. Once again, it becomes magma and may eventually be pushed up and out of a volcano.

Then, guess what. The whole process starts all over again. Have a look at this animation

This one is also very good. Compare them.

Metamorphic Rocks

Coarse grained kinked gneiss - a metamorphic rock

Metamorphic rocks are rocks that have changed.
The word comes from the Greek “meta” and “morph” which means to change form.  Metamorphic rocks were originally igneous or sedimentary, but due to movement of the earth’s crust, were changed.

If you squeeze your hands together very hard, you will feel heat and pressure.
When the earth’s crust moves, it causes rocks to get squeezed so hard that the heat causes the rock to change.
Marble is an example of a sedimentary rock that has been changed into a metamorphic rock.

  • Metamorphic rocks are the least common of the 3 kinds of rocks.
    Metamorphic rocks are igneous or sedimentary rocks that have been transformed by great heat or pressure.
  • Foliated (leaf-like) metamorphic rocks have layers, or banding.
    • Slate is transformed shale. It splits into smooth slabs and roof tiles are made from it.
    • Schist is the most common metamorphic rock. Mica is the most common mineral.
    • Gneiss has a streaky look because of alternating layers of minerals.

Sedimentary Rocks

Canadian Rockies

When mountains are first formed, they are tall and jagged like the Rockies. Over time, millions of years, mountains become old.

Old Mountains - the Appalachians

When mountains get old, they are rounded and much lower. What happens in the meantime is that lots of rock gets worn away due to erosion. In a rain, freeze/thaw cycle, wind and running water cause the big mountains to crumble a little bit at a time. Eventually most of the broken bits of the rock end up in the streams & rivers that flow down from the mountains. These little bits of rock and sand are called sediments.  When the water slows down enough, these sediments settle to the bottom of the lake or oceans they run into.  Over many years, layers of different rock bits settle at the bottom of lakes and oceans. Think of each layer as a page in a book. One piece of paper is not heavy. But a stack of telephone books is very heavy and would squash anything that was underneath.  Over time the layers of sand and mud at the bottom of lakes and oceans turned into rocks. These are called sedimentary rocks. Some examples of sedimentary rocks are sandstone and shale. Sedimentary rocks often have fossils in them.

Trilobite fossil from South Africa

Plants and animals that have died get covered up by new layers of sediment and are turned into stone. Most of the fossils we find are of plants and animals that lived in the sea. They just settled to the bottom. Other plants and animals died in swamps, marshes or at the edge of lakes. They were covered with sediments when the lake got bigger. When large amounts of plants are deposited in sedimentary rocks, then they turn into carbon. This gives us our fossil fuels, coal, oil, natural gas and petroleum.

Igneous Rocks

Towering nearly 400m above the tropical stillness of the Sunda Strait in Indonesia, one of the most terrifying volcanoes the world has ever known has begun to stir once more. 126 years since Krakatoa first showed signs of an imminent eruption, stunning pictures released in July 2009 prove that the remnant of this once-enormous volcano is bubbling, boiling and brimming over. Last time, the bang when it erupted was heard 4,000km away.This time there are thousands of people living under its shadow…

When volcanoes erupt and the liquid rock comes up to the earth’s surface, then new igneous rock is made. Igneous means made from fire or heat – from the Latin ‘ignis=fire‘. When the rock is liquid and inside the earth, it is called magma. When the magma gets hard inside the crust, it turns into granite.
Most mountains are made of granite. It cools very slowly and is very hard.

When the magma gets up to the surface and flows out, like what happens when a volcano erupts, then the liquid is called lava.  Lava flows down the sides of the volcano.  When it cools and turns hard it is called obsidian, lava rock , basalt or pumice – depending on what it looks like.

  • Igneous rocks form when molten lava (magma) cools and turn to solid rock.  The magma comes from the Earth’s core which is molten rock .
  • Obsidian is nature’s glass. It forms when lava cools quickly on the surface. It is glassy and smooth.
  • Pumice is full of air pockets that were trapped when the lava cooled when it frothed out on to the surface.  It is the only rock that floats.

There are 5 kinds of igneous rocks, depending on the mix of minerals in the rocks.

  • Granite contains quartz, feldspar & mica
  • Diorite contains feldspar & one or more dark mineral. Feldspar is dominant.
  • Gabbro contains feldspar & one or more dark mineral. The dark minerals are dominant.
  • Periodotite contains iron and is black or dark.
  • Pegmatite is a coarse-grained granite with large crystals of quartz, feldspar and mica.

Here’s a few pictures…

Feldspar can be either sodium, potassium, or calcium aluminium silicate
Quartz is pure crystalline silicon dioxide

Mica is particularly interesting.

Mined from the earth in thin sheets, this mineral is extremely finely ground for use in cosmetics such as eyeshadow, mineral makeup, powder, lipstick, and sometimes nail polish.

The word mica comes from the Latin word “micare,” meaning to shine or glitter.

There are almost 50 different varieties of mica. They has a general formula

AB2-3(X, Si)4O10(O, F, OH)2

where A can be either potassium, sodium or calcium, B can be either aluminum, lithium, iron, zinc, chromium, vanadium, titanium, manganese and/or magnesium and X is usually aluminium, all the other symbols having their usual meanings.

Have you noticed? Often, transition metals are present. This is what gives the crystals their colours. Finally, here’s some polished malachite. It contains copper, so this gives it its green colour. It’s copper carbonate mostly and is formed by reactions between other minerals and water. It would be more correct to say that malachite is therefore metamorphic – see next post.

Rocks, an Introduction

The climber is climbing a granite rock face

Rocks are all the same, aren’t they? Well, not quite. Much of the Earth’s crust is covered by water, sand, soil and ice. If you dig deep enough, you will always hit rocks. Sometimes, of course, they are on the surface and people climb them!

  • The Crust makes up less than 1% of the Earth’s mass (0.4%)
    It is made of oxygen, magnesium aluminum, silicon calcium, sodium potassium, iron.
    There are 8 elements that make up 99% of the Earth’s crust.
    The continents are about 35 km thick and the ocean floors are about 7-10 km thick, but the oceanic rock is denser.
  • The Mantle is the solid casing of the Earth and is about 2900 km thick.
    It makes up about 70% of the Earth’s mass (68.1%).
    It is made up of silicon, oxygen, aluminum and iron.
  • The Core is mainly made of iron and nickel and makes up about 30% of the Earth’s mass (31.5%).
    The Outer Core is 2200 km thick and is liquid and the Inner Core is 1270 km thick and is solid.

A rock is made up of 2 or more minerals.

Think of a chocolate chip cookie as a rock. The cookie is made of flour, butter, sugar & chocolate. The cookie is like a rock and the flour, butter, sugar & chocolate are like minerals.
You need minerals to make rocks, but you don’t need rocks to make minerals. All rocks are made of minerals. A mineral is composed of the same substance throughout. If you were to cut a mineral sample, it would look the same. throughout.
There are about 3000 different minerals in the world.
Minerals are made of chemicals we’ve seen or heard about before and are sorted into 8 groups.
Some common examples have been listed for each.

  • Native Elements~ copper, silver, gold, nickel-iron, graphite, diamond
  • Sulphides ~ sphalerite, chalcopyrite, galena, pyrite
  • Halides ~ halite, fluorite
  • Oxides& Hydroxides ~ corundum, hematite
  • Nitrates, Carbonates, Borates ~ calcite, dolomite, malachite
  • Sulphates, Chromates, Molybdates, Tungstates ~ celestite, barite, gypsum
  • Phosphates, Arsenates, Vanadates ~ apatite, turquoise
  • Silicates ~ quartz, almandine garnet, topaz, jadeite, talc, biotite mica

Some people make up stories and legends about rocks. These amethyst crystals in the picture are sometimes naturally hollowed out into ‘geodes’ where the ‘little people’ were supposed to live!

The Structure of our Planet

The Earth is a ball of diameter about 12,800km, which means  a journey of nearly 40,000km all the way round – quite a long way.It’s a little bit like an eggshell. The atmosphere is an incredibly thin protective layer of gas that stops the sun from frying us or us freezing to death, sitting over a thin crust between 30 and 40km thick. The deepest places we’ve been to on the earth are in South Africa, where mining companies have excavated 3.5 km into the earth to extract gold. No one has seen deeper into the earth than the South African miners because the heat and pressure felt at these depths prevents us from going much deeper.

The crust is in the form of plates – called tectonic plates – which once fitted together.  Over time, the plates have actually moved huge distances – South America once fitted nicely into West Africa like pieces of a jigsaw puzzle. When earthquakes happen, the rock layers can jolt over each other and the shockwaves can damage buildings and sometimes kill a lot of people. The recent earthquakes in Haiti and Chile caused many deaths and a great deal of damage.

Underneath the crust is the mantle, some of which near the crust is molten. Sometimes, the molten material has to escape and a volcano erupts. It is a much thicker layer than the crust. Beneath that, there’ a core which might even be solid because the pressure is so very high, which contains a lot of iron and nickel – making the Earth a magnet.

Here’s an animation of how the continents moved apart…