To gain a better knowledge of the properties of objects and the dangers they are exposed to, it is important to have a better insight in their composition and the processes that have a negative impact on them.

This insight demands a basic knowledge of chemistry, physics and biology. Because not everybody involved in art and cultural heritage has this knowledge (maybe because it was never learned or maybe partly forgotten) we want to provide this basic knowledge through our blog/site. Sometimes we use a more simplified way for a better understanding.

Today we start with “THE ATOM”.

What is an atom?

The word “atom” is derived from the Greek word “atomos” which means ‘indivisible”. The ancient Greeks thought the atom was the smallest particle in the universe and that it was indevisible. Today this idea is outdated.

But the atom remains the smallest building block of which all matter and materials, as well vegetable as animal or mineral are composed of. Atoms are the “lego blocks” of nature. There are different kinds of atoms. They have a different composition and different properties and can be combined to form living materials or non-living materials. The way they combine happens according to coded instructions inherent to nature. These instructions can be of a physical or chemical nature. They are a kind of “manuals” according to which the building blocks are combined to form an entity. Because these “manuals” are often more “guidelines” instead of a strict program, it is possible to find a lot of variations on the theme, especially in living materials. Living creatures or objects composed from once living matter we call “organic”. Non-living materials we call “inorganic” (= non-organic).

How is an atom structured?

Atoms have a diameter of about one tenth of a million of one millimeter. This is very small and invisible for the naked eye even using a normal laboratory microscope.

An atom consists of smaller particles of which we will only mention the ones most important to our purpose: protons, neutrons and electrons. The most simple representation of an atom is comparable to our solar system: a central core (consisting of protons and neutrons) around which circulate smaller objects (electrons). In practice the system is more complicated. The electrons move at a crazy speed aorund the core and not in planetary orbit as our planets, but criss-cross through a spherical or elliptical space around the atom core.

256px-Sciences_exactes.svg

Representation of atom (Adrien Facélina)

The amount of protons can be equal or not to the amount of neutrons. In an atom there are always as many protons as electrons. Protons have a positive electrical charge, electrons a negative electrical charge. This way the particles keep each other balanced. Neutrons do not have electrical charges.

The core of an atom is very small. The diameter is about 1/1000 of the total diameter of the atom. The electrons are smaller still. Everything in between is empty space, which allows for a lot of movement. All objects, even living creatures are thus composed of a lot of empty space.

There is a whole variation of atoms. This is based, amongst others, on the different amount of protons and neutrons in the core. The properties of these atoms are therefore different. Atoms can contain up to 92 protons. Based on the amount of protons the atoms have received what we call an “atom number”. All these atoms occur in nature. Number 92 is uranium. Every type of atom has specific properties and behaviour and react in specific ways with other atoms. There are also atoms with a higher atom number (up to 118 nowadays), but these atoms are not occurring spontaneously in nature. They can only be synthesized with scientific equipment.

The table of Mendelejev

Based on the diversity of properties the Russian Dmitri Mendelejev devised a clear table of elements for all known atoms in his time. Elements have been added to this table when they became available. This table shows the various relations between the different atoms.

periodic-system-1059755_1280

Table of Mendelejev (DePiep)

Names and symbols

Each atom is represented by a letter symbol. Mostly, but not always these are the first letter(s) of the Greek or Latin name for the atom. So the letter H stands for Hydrogenium (Hydrogen), He for Helium (Helium) and Cl for Chloros (Chlorine).

In conservation practice we will encounter often the same atoms. That is why it is important to know the exact names, shortenings and properties of these atoms. Lacking the right knowledge can have a large impact on conservation and survival of materials.

The most occurring atoms we will work with are: H (hydrogen), C (carbon), N (nitrogen), O (oxygen), P (phosphor), S (sulfur), Cl (chlorine). Depending on the materials we work with we will also need knowledge of Na (sodium), Mg (magnesium), Al (aluminium), Si (silicium), K (potassium), Ca (calcium), Fe (iron), Ni (nickel), Cu (copper), Zn (zinc), Ag (silver), Sn (tin), Au (gold) and Pb (lead).

In a next post we will cover the interaction between identical and non-identical atoms.

Guy De Witte

We thank our sponsors for their generous support

cami_nv_logo  truvue-weblogo

LOGO-DE-ZILVEREN-PASSER

People who are acquainted with me will know that climate change and its possible impact on life on earth has always been a topic I have been interested in. My first confrontation with climate change dates from 1972 when the Club of Rome published their report “The Limits to Growth”. At that time is was already clear that Humanity lived above its means and that sustainability would become a hot topic in the future.

Through the years sustainability has become more and more important, also due to the actual climate change, of which we gradually start to see and feel the consequences.

Since I am professionally involved in conservation of cultural heritage it was a logical step for me to get more and more involved in analyzing data and extrapolating possible repercussions on art and cultural heritage.

That is why I chose, in 2006 : “Archives in a Changing World: An Exploration into Sustainable Building for Archives in Belgium in Response to Global Climate Change.” as title for my thesis to acquire my Master in Preventive Conservation at Northumbria University in Newcastle (UK).

The result was an invitation by the organisers of the “Going green” conference in the British Museum (Clore Education Centre) in 2009 to present a paper named: “New Challenges demand new solutions: The Integration of Sustainable Building and Functioning of Archives as a possible response to Climate Change.”.

The same year I produced an article for the magazine Faro (published by Faro, a leading cultural heritage organisation of the Flemish government), with the title: ”Klimaatverandering en duurzaamheid. Sleutelwoorden voor een nieuw erfgoedbeleid (”Climate Change and Sustainability: Keywords for a New Cultural Heritage Policy”).

Since then I try to get climate change more and more on the cultural agenda by giving talks about the threats posed to our cultural heritage. One of the examples is the serie of talks called “Buitenbeentjes” (Mavericks) in 2012 where I asked the question: “Can the World save its Heritage”.

Screen Shot 2016-04-28 at 01.06.04

Foto: Guy De Witte: "Can the World save its Heritage?"

The last paper was at the conference “Art meets Security 2015”, where I talked about: “Climate Change: a Global Threat to Art and Cultural Heritage”.

My students of the courses in Cultural Heritage Education, Archive Education and Master in Cultural Heritage and Temporary Document Management are every year again made aware of this growing problem.

Even so I notice that in Belgium and some other countries the awareness of the impact of climate change on our cultural heritage is still minimal and that although large international organizations are discussing how to tackle the problems, most institutions are only focused on local institutional issues. That way they miss the big picture and decisions taken on a local level for improving conservation conditions may be contraproductive in the long haul. This is a pity since the problem begins to be urgent and future policies will have to take climate change more seriously. This will be the only way to mitigate and manage the oncoming problems.

Climate change will as well have a large macroscopic as a microscopic impact on the survival of cultural heritage. Macroscopically whole sites are threatened such as the natural sites of the Great Barrier Reef in Australia and the Kilimanjaro National Park in Tanzania. But also known archaeological sites as Chan Chan and the Machu Picchu complex in Peru are very vulnerable.

However the threat does not limit itself to these sites. Hundreds of cities all over the world are threatened. Two thirds of all cities with more than 5 million people are situated less than 100 km from the coast. Nearly 650 million people leave on land that is less than 10 meter above sea level. In Europe Denmark, part of the coast of England, Belgium and especially The Netherlands are in the danger zone. It is also in all those cities, close by the sea, that we find the largest concentration of art and cultural heritage. It is a quantified certainty that cultural heritage is now threatened worldwide.

International organizations such as UNESCO, ICOMOS and ICCROM sounded the alarm-bell already years ago. UNESCO published in 2007 a publication called: “Case Studies on Climate Change and World Heritage”. In this publication cities as London, Venice, the heart of Prague and Timbuktu (Mali) are considered as threatened. In London it concerns the complete site of Westminster, the National Greenwich Museum and the Tower. Venice is completely threatened, not only because the sea level rises but also because the city is sinking into the lagoon.

Screen Shot 2016-04-28 at 01.25.42

Foto: Unesco Publication

For The Netherlands the situation will become dramatic over time. One third of the country lies below sea level and the water level of its main rivers. It is protected by dunes, dikes and the Delta Works flood barrier, an ingenious flood barrier system. Even so, nobody can guarantee that climate change cannot alter this situation. If massive flooding occurs there will not only be human casualties (cfr. the flood in 1953), but cultural heritage will suffer a considerable damage and loss.

Flanders lies above sea level, but still quite low, which makes it also vulnerable. Large pieces of the provinces of West-Flanders, East-Flanders and Antwerp are lower than 30 m above sea level. This may seem much, but a combination of low height with high tide and heavy storms can produce serious flooding, which can cause irreversible damage to heritage collections and buildings. In practice the cities of Bruges, Ghent and Antwerp are all three within the danger zone.

Screen Shot 2016-04-28 at 01.28.16

Foto: Alex Tingle's Flood Map (2007) 

Many countries have set up flood maps and flood warning apps that you can find on-line easily. Alex Tingle, an ICT programmer, developed already in 2007 a flood map based on information from Nasa. The map is not correct because not all parameters were taken into account, and science has progressed a lot since then. Anyway it gives a rough idea how sea level rise affects countries. The map is interactive and the sea level can be adjusted. Is this a realistic picture? We do not know for sure but it is an exercise in learning what can happen. The absorption of CO2 by the oceans causes a rise of the water temperature. The consequence of this heating up is an expansion of the water volume, even if not a single drop of water is added by melting ice from glaciers or ice-caps. This means that the ocean level rises, and even if it takes a few hundreds of years before reaching the maximum expansion, computations predict that this phenomenon will be responsible for a sea level rise of 8m worldwide. According to Nasa sea level has risen 22,6cm from 1880 to 2013. And if Nasa’s projections become reality, sea level could rise another 90cm, maybe more by the year 2100, thus becoming one of the most important problems we have to face.

NASA1

Foto: Nasa - Sea Level Rise

An important aspect of climate change is the expectation that the weather patterns will become more capricious. The effects will be different in different parts of the world. For Western-Europe extreme higher summer and winter temperatures can be expected, although cold winters will still occur. Weather phenomenons can become freakish, with periods of very intense rainfall alternating with long periods of drought. Storms can produce so much rain in a short time that rivers cannot swallow the water and swell to flood the country. Periods of intense drought can provoke subsidence leading to cracks in walls, letting water easily penetrate into buildings. For underground cultural heritage storage rooms this would be a nightmare.

Other aspects of climate change as a rise in temperature, raises the reaction velocity of chemical deterioration processes in cultural heritage objects and can stimulate mould development and the introduction of new harmful insect species.

How quick climate change will affect our lifestyle quite thoroughly we do not know yet. Will the change occur gradually or in jolts? How big will the impact be on Humanity and its cultural heritage? If the projected scenario’s of the International Panel on Climate Change and Nasa are correct we will be faced with the question in how far we will still be able to protect our cultural heritage. How will we tackle this problem, locally and internationally? Will we have to give up part of our heritage to save the most important sites and collections? Which ones will we choose to keep? Who will decide what to keep? Will we have to spread our heritage all over the world to avoid total loss?

It is five to twelve for our cultural heritage. Politicians, policy makers, curators, scientists and conservator-restorers have to think urgently about what we can possibly do. Just as in medecine prevention is of utmost importance here. We still have some time but we will have to use it usefully. Burying one’s head in the sand is no option. Sooner or later there will be a verdict. It is our responsibility to decide if we want a word in the matter or not.

Guy De Witte

All pictures are copyrighted unless stated otherwise.

We thank our sponsors who make this blog/site possible

cami_nv_logo  truvue-weblogo

LOGO-DE-ZILVEREN-PASSER