C R E A T I N G a C R Y S T A L
Q U E S T I O N S
1.Crystals are solid material where ions, atoms and molecules fit together in a repeated pattern. These different patterns cause the material of the crystal to form unique shapes. The charge of a crystal is neutral in order for it to grow and form.
2. Naturally formed crystals can take millions of years to form once the liquid inside the Earth has cooled and hardened. Crystals made from human commonly take shorter amount of time and they can be made out of salts, ice and dry ice such as sodium chloride and various metals.
3. Crystals are grown naturally deep within different surfaces, such as rock caves and the Earth’s surface. They can grow is mineral rich solutions in spacious areas such as rock cavities or molten rock.
4. Crystals are grown in a solution that can only hold a certain amount of solute. This is called the solubility of a solution. When the temperature of the solution is increased, hot water dissolves more solid substance than the cold water. This is because heated water molecules tent to move farther apart, making room for more solid substance to dissolve as well. When no more of the solid substance can be dissolved, the solution is then called ‘saturated’. As this solution cools, the water molecules then move closer together again and there's less room for the solution to hold onto 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 recrysallization and depending on conditions, it may grow many small crystals or one large crystal.
5. Crystals grow into certain shapes, sizes and colours because the atoms or molecules join together in a certain pattern that repeats itself over and over to create a certain shape. A crystal grows by adding atoms or molecules to all its sides in the exact same pattern as the atoms and molecules that were added before this. Because each different crystal is made up of a different building block (atom or molecule) they each have a different structure, shape and colour. Also depending on the growing conditions, the crystal grows at different speed and may affect the resulting size.
6. Different types of crystals may include; salt crystals, metallic crystals, ionic crystals, molecular crystals and covalent crystals.
7. When light travels through a crystal, it is refracted. When travelling from a less dense medium into a crystal, the light bends towards the normal. When the light exits the crystal, because of the many faces, the light disperses in different directions.
8. The optimum growing conditions are warm surroundings, including warm solution and warm air temperature. Crystals will still grow in cooler temperatures, but it will take longer for the water to evaporate. Crystal growth also requires light but the crystals will eventually grow in the dark, but it will take a very long time.
M E T H O D
T U E S D A Y
· Two 250mL beakers
· Filter funnel and filter paper
· Stirring rod
· Place 25g of potash alum in one beaker and add 170mL of hot water. Stir the mixture until all of the particles are dissolved. (Note- Don’t use all the alum).
· Then, filter the warm solution through a filter funnel (in which filter paper has been inserted) into another clean beaker. Cover the beaker of solution with r fresh filter paper and set aside in a cool, sheltered place and allow it to stand overnight.
W E D N E S D A Y
· Clean beaker
· Nylon thread
· Pencil or Stirring rod
· Ruler – if possible
· Observe the beaker, and look for any major changes. The bottom should be layered with a small layer of crystals which formed while the solution cooled.
· Carefully pour the clear solution above the crystals into a clean beaker and set it aside for later.
· From the bed of crystals, one crystal needs to be selected as “seed” for the main crystal. Using the tweezers, transfer the selected “seed” crystal into the beaker containing the used solution whilst trying to place it centrally in the beaker. A technique to promote growth is to suspend the crystal with a nylon thread tied round a stirring rod or pencil resting on the rim of the beaker. This step is not essential.
· Take a picture of the crystal next to a ruler for the first stages of the crystal growth.
P H O T O S
Picture 1: This is a picture of the very start of the crystal growing. We are pouring the Potash Alum into the hot water through a filter paper.
Picture 2: This is a picture showing how high the solution is both in mL and cm. The solution is approximately 175 mLs and 4.5 cms.
Picture 3: This is a picture of our solution after standing for one night. There is only one crystal at the bottom and it is quite large.
Picture 4: This is a picture of the same solution but this was after it had been standing for two nights. More crystals have grown over the second night but they are smaller than the first.
Picture 5: This is a picture of the first day of the crystal being moved into the jar. There is one big crystal amongst littler crystals.
Picture 6: This is also a picture of the crystal being moved on the first day, just from from birds eye view.
Picture 7: This is a picture of the crystal with fishing wire wrapped around it to help support it and to keep it in the middle of the jar.
Picture 8: This is a picture of the crystal being supported by a highlighter with the fishing wire wrapped around it.
Picture 9: This picture is taken on day 8 of the Crystal Project. This is showing that the solution level has dropped (evaporated) throughout the 8 days. It also shows the crystal hanging by the fishing wire.
Picture 10: This picture is showing high high the solution level is. The solution in approximately 3cm high in this picture.
Picture 11: This is a picture of day 11 of the crystal making. The picture shows the crystal hanging from the fishing wire with the protective cover over the top (paper hat). It also shows that the solution level has dropped from the start.
Picture 12: This is a picture of the crystal closer up.
Picture 13: This is a picture on day 15 of the crystal. The light is shining on the crystal in hopes that the solution will evaporate making the crystal grow a little faster.
C O N C L U S I O N
My crystal hasn't really grown over the 4 weeks of this assessment. However, it has grown to take on more of a crystal like shape with what looks like lots of crystal joined as one. The liquid level of the substance went from 4cms on a ruler down to 2cms.
In the images below, you can see the definition of the edges of the crystal. The crystal has become 2cms exactly whereas when it first started it was 2.6cms meaning that it has lose .6cms of its diameter.