Salt Crystals
When sea water evaporates, salt is obtained. While in water, the sodium (Na) and chlorine (Cl) are separated by water molecules (H2O). As the water starts evaporating from the solution, the Na and Cl ions begin to bond together as single molecules, and then the molecules bond together, forming crystals. It is worth noting that every molecule builds itself into the same shaped crystal, a cube, each time it forms.
How are crystals grown?
In a solution, a solvent (water) can only hold a certain amount of solute. This is called thesolubility of a solution. When the temperature of the solution is increased, hot water can dissolve more solid substance than cold water. This is because heated water molecules move farther apart, making room for more solid substance to dissolve. When no more of the solid substance can be dissolved, the solution is said to be saturated. As this solution cools, the water molecules move closer together again and there's less room for the solution to hold onto as much of the dissolved solid. Crystals begin to form and build on one another as the water lets go of the excess solute. This process is called recrystallization and, depending upon conditions, one may obtain a mass of many small crystals or one large crystal.
How do crystals form and how do we control its rate of growth?
In this experiment, you will be growing crystals from a saturated solution. During recrystallization, crystals start growing by a process called "nucleation". Particles of dust on the surface of the solution can initiate crystalization. However, this situation is somewhat uncontrolled. To get controlled growth, a "seed crystal" is tied on a piece of thread and is submerged in the solution. As the temperature of the solution continues to drop, more crystals will accumulate on the thread. The rate at which crystallization occurs will affect crystal quality. The best crystals are the ones that grow SLOWLY.
- instructables.com
Facts about salt:
- You eat crystals whenever you eat salt.
- Greeks used to exchange slaves for salt, therefore the expression "he is not worth his salt."
- In Tibet, tiny cakes of salt were pressed and used as coins.
- Roman Legionnaires were paid in salt (salarium, the Latin origin of the word salary).
- It was used to preserve Egyptian mummies.
- In 1933, Dalai Lama was buried sitting up in a bed of salt.
- These crystals are used to manufacture thousands of products.
- Salt helps preserve food items.
- Each and every cell of your body contains salt. An adult human body contains about 250 grams of salt, which help the body systems to function properly.
- In India, a gift of salt is considered as a potent symbol of good luck.
- Until relatively recently, salt bars were the standard currency of Ethiopia.
- One of the interesting facts is that in spiritual tradition, people use these crystals to cleanse themselves of negative vibrations.
- Salt intake is necessary, as it is the key element in the process of perspiration, which is considered as a vital process that helps to maintain your body temperature.
- In Buddhist and western spiritual traditions, salt is believed to repel evil spirits. It is a well-known fact that in old Japanese theaters, salt crystals were sprinkled on to the stage before each performance to prevent evil spirits from casting a spell on the actors.
Reflection
What first attracted me to using salt as a material was a thought I had whilst on the bus in Colchester, I suddenly starting thinking about the road we were travelling on and how straight it was, this in turn lead to and conversation in my head about how the Romans would salt the ground of their enemy so that the ground could no longer grow crops, this thought then lead me thinking about the qualities of salt and how it would also be used to purify or preserve foods. From there I applied that to a conundrum I was having at the time about how to preserve an memory, or at least stop it from gathering additional charges (A thought I have been having after reading an essay from the book The Object, by Issa Samb and Antje Majewski entitled 'How to make objects talk') I decided salt has many uses though-out the centuries and it would be interesting to re-purpose an ancient material and use in for a contemporary artwork.
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