The Elements versus The Periodic Table

Two iPhone Apps. Theodore Gray's 'The Elements' (left) or Merck's PSE-HD (right). Both apps are shown displaying basic information for Technetium.

Did I mention I had a new iPhone? Well obviously the first kind of app I downloaded was a periodic table of the elements – it just gave me a comfortable feeling knowing that I had that information close at hand. And what could be better than a Periodic Table app? Well, obviously two Periodic Table apps! And so here I compare the free Merck(TM) PSE HD app with the £6.99 app called ’The Elements’.

'The Elements' page for Technetium. Touching the image allows you to rotate it and the text scrolls for an engaging description of the element.

The Elements is an app written with love by Theodore Gray, co-founder of Wolfram Research who make Mathematica. It is a simple app to understand and navigate. It has an introductory essay, a picture of the periodic table with animated pictures of each element, and splendid animation of the ‘The Elements’ Song by Tom Lehrer. Tapping on an element brings up a screen with a rotatable picture of the element, and an engagingly written essay by the author. I did find a tiny error on the page about Helium, but Theodore said he would fix that in the next release. Each essay links the physical properties and the history of the element and has links to the pages for other relevant elements (this makes it easy to browse and ‘get to know’ the elements).

The main attraction of this app is its accessibility – it is simple to use and a pleasure to interact with – one of those apps you will show your friends to make them think that your insanely expensive mobile phone might not have been a complete waste of money. On the down side, it is a bit limited and expensive as apps go. It does have links to Wolfram Alpha’s database on the elements, which is nice, but then you are back to browsing web pages.

Link to UK App Store

The Merck PSE (HD) has more data built-in to the app than The Elements, and it has many different ways to display and interact with the data. The main screen is a picture of the periodic table, and touching an element brings up a panel with basic information. Touching the panel causes it to flip and on its reverse are different categories of information shown in considerable detail, from the history and discovery of the element, to technical data. At this point the app is just ‘really useful’. But there is more: touching the Merck ‘M’ on the home screen brings up a new way of viewing the data where one can view how a property varies across the periodic table.

Turning the control increases the temperature, and the periodic table graphically shows which elements are solid, liquid, and gas at that temperature.

For example, selecting ‘state at room temperature’ allows one to view the periodic table colour-coded as to the state (solid, liquid or gas) of the elements. A rotary control allows one to change the temperature and see visually which parts of the table melt and then vaporise in which temperature range: it is delightful. Similarly, selecting electronegativity shows how this property varies across the periodic table. Not sure what electronegativity is? Then select the glossary tab to find out.

The periodic table graphic shows how the electronegativity of a substance varies with position in the table.

My favourite is the discovery tab which allows you to scroll back through time and see when each element was discovered – and the app displays an image of the discoverer. And there is lots more too.

The faces of the people who discovered each element.

This app is data rich and carefully thought out. Having it on your phone gives you that comfortable feeling, knowing that even when your network connection is down, you will still have access to melting point data for the elements

Link to UK Apple App Store and  Android marketplace

Which is best? For people who enjoy tech lore, or if you’re studying Physics or Chemistry, then the Merck PSE app – for free – is a must have . For people who have £6.99 to spare – and are perhaps curious about science – but not professionally involved, ‘The Elements’ is a real pleasure to own.

A Silent National Disaster

At Protons for Breakfast I try to make the world of science accessible to ‘normal’ people i.e non-scientists. I use no maths, because the course is about ideas, but I do use words. However many adults in this country can’t read. And so there is universe of ideas to which these people don’t have access.

People who can’t read generally don’t make a fuss: they are embarrassed. And after they have left school, their whole lives are in no-small-part defined by their inability to read. And one in five adults in the UK is functionally illiterate.

Two fantastic friends of mine – Nick Ainley and Libby Coleman – have written a book and started a practical campaign to help any one person teach one other person to read. It’s called Yes we can read. They aim to reach non-readers one by one. At the moment their work is still a ripple, but I think it will become a wave.

Nick and Libby: You are my heroes.

Ground Source Heat Pumps are Solar Powered

A simplified estimate of how the temperature of soil at selected depths varies through the year. Notice that at depth, the variations are minimal and lag behind the variations at the surface. However the average temperature is roughly the same as the average surface temperature, in this case 10 °C. Data are guesstimates adapted from here : please do not trust them! Click for larger version.

Sometimes I astonish myself with how stupid I can be.

At Protons for Breakfast last autumn I stated that geothermal energy supplies could only ever extract around 0.1 watts per square metre of ground. Why? Because that’s the average rate at which heat rises through the Earth. This is a ridiculously low figure, and I couldn’t understand how it made any sense. And then it clicked.

• Geo-thermal energy isn’t sustainable, at least on a strict definition. It’s a one-shot operation that cools a reservoir over a decade or so, and then waits a few decades for the reservoir to heat up again.
• Ground Source Heat Pumps don’t capture Geo-thermal energy – they capture Solar Energy and there is on average over the Earth around 240 watts per square metre of solar energy available.

I realised that I had confused these two sources for years, and browsing the web makes me think a lot of other people have too. Let me explain.

Geothermal energy is the heat flowing outward from the centre of the Earth. It arises in part from the radioactive decay of elements within the Earth, and in part from heat left over from the formation of the Earth. The Earth’s crust is an excellent insulator and the heat only flows out slowly. Across the UK, the average heat flow is just 0.038 watts per square metre, which means that in order to generate the 10 kW one needs to heat a house, one requires an area of around 500 metres x 500 metres – and drilling down doesn’t increase this figure at all. However there are two situations in which we can extract this heat and use it.

1. In areas of the Earth where the heat flow is stronger than average (e.g. Iceland) it would be perverse not to exploit the gift of heat.
2. The second situation is more common and involves drilling down to around 3 km depth where the temperature is around 100 ºC. If the rocks are porous at this depth then we can pump cold water in to the rocks, and extract hot water. The porosity of the rock allows the water to accept heat from a large volume of rock. This is not strictly sustainable in that the block of rock will cool down over a few years, and we will need to leave it to warm again. But it will keep warming up for millions of years to come.

Both these schemes extract genuine geothermal energy, which originated on Earth, roughly one half it, nuclear in origin.

Ground Source Heat pumps collect heat in the top few metres of the Earth and here the temperature is strongly affected by the temperature of the surface. And  this is determined by the  local average heating from the Sun, typically around 240 watts per square metre. Even in areas with cold winters, if one digs down more than a few metres, the soil stays warm , and a heat pump can be used to extract this heat. The pump chills a fluid such as ammonia to around 3 °C and then passes it through the buried pipes. Being colder than the surrounding soil, the ammonia absorbs heat from the soil, and evaporates. When compressed, the heat is released at a temperature of around 20 °C which can be used to heat a house.

However the source of the energy is the Sun not the Earth, and so 100% of it comes from nuclear fusion.

Global Warming Mug

I got a Global Warming Mug for my birthday!

The blurb:

• Have you ever wondered what the world would like if the polar ice caps melted?
  •  Now you can ponder the question over a cup of tea
• WATCH land mass get swallowed by Atlantic
• SEE Valuable water front property get turned into a modern day Atlantis

I certainly hope the mug exaggerates the imminent effects of Global Warming.

P.S. Thanks to Andrew & Sharmila

Arctic Sea Ice: Volume and Area

An estimate of Arctic Sea Ice Volume from 1980 to the end of 2011. Notice that the trend on the minimum volume, which occurs in the Arctic summer, looks as if it will reach zero within the next decade. Click on the graph for a larger version.

I have mentioned previously that the area of sea ice in the arctic is showing a dramatic decline – at the least the Financial Times thinks so. The area of sea ice is relatively straightforward to monitor from satellites, and data is available here. But what about the volume of the sea ice?

If the area is shrinking, one would have to guess that there would be some effect on ice thickness as well. This is not straightforward to measure, or to model, but this week I came across a pretty terrifying estimate of how the sea ice volume is varying. The data from the Polar Science Centre is available here and there is a commentary on the data here. The full dataset is shown on the graph at the head of the page. Shockingly the implication is that the minimum volume of sea ice could reach zero – i.e.no arctic sea ice in the summer – sometime around 2020.

Of  course there is significant uncertainty in this model, and it could be just wrong. Arch climate skeptic and contrarian Anthony Watts certainly thinks so. Personally I am prepared to let time be the judge – it doesn’t look like we will have to wait for many summers before the truth becomes clear.

Looking on the bright side, perhaps this is the shock we need.  As we have seen repeatedly, countries such as the USA and China are able to use scientific uncertainty as an excuse for their understandable reluctance to change. This may not convince climate scientists, but it is enough to convince a fair proportion of their electorate who too are understandably reluctant to change. I think if the entire Arctic ocean melted one summer soon, that this could be a wake up call to us all. Let’s hope so.