1. What is a crystal?
A crystal is defined as a solid material in which the atoms and molecules, are arranged in a consistent, repeating pattern that extends repeatedly in a three-dimensional pattern.The structures of crystals depend on the types of bonds between the atoms and the conditions under which the crystals are formed.
2. What substances are used to make crystals?
Aluminium chloride, ammonium, Potassium alum, Sodium nitrate, Sodium Borate, Calcium chloride, Copper sulfate, potash alum and many more are used.
3. What are some examples of crystals in nature?What household items can you use to grow crystals?
Many types of crystals are found in nature. Snowflakes,diamonds, and common salt are well-known examples. Various minerals are the raw materials from which metals are extracted, and the metals themselves have crystalline structures.You can easily make your own crystals at home using epsom salt. Epsom salt is another name for the chemical magnesium sulfate. The temperature of the water determines how much magnesium sulfate it can hold; it will dissolve more when it is hotter. Cooling the solution rapidly encourages fast crystal growth.
4. Explain the process of crystal growth
Crystals form beneath the Earth's surface. Igneous creation occurs when minerals crystallise from melting rocks. Metamorphic creation occurs when minerals form due to excessive pressure and heat. Sedimentary minerals form from erosion. Water, temperature and pressure all play a role in the creation of crystals.
5. Explain how crystals can grow in different shapes and sizes?
Crystals are atoms that are arranged in regular geometric shapes. The varying shapes of crystals has to do with its formation. Factors that go into the formation of crystals, which lead to differing shapes, are temperature, pressure, and chemical conditions.
6. Outline a few different types of crystals
Amethyst is a member of the quartz family, and considered a master healer. Coloured by iron, amethyst usually forms geodes of densely packed short crystals all pointing inwards towards the centre of the hollow.
Sapphires can be found naturally, by searching through certain rock formations. They can also be manufactured for industrial or decorative purposes. Because of the remarkable hardness of sapphires and of aluminium oxide, sapphires are used in some non-ornamental applications, including infrared optical components, such as in scientific instruments.
7. What effects do crystals have on light travelling through them?
Light is not expected to affect the process of crystal growth. The only time that it might have to do so is if the growing crystals are light sensitive -- for example, crystals of silver bromide and silver iodide (which are the stuff of photographic film) would decompose to silver metal when exposed to light so if one is growing crystals of these materials, one does it in the dark.
8. What are optimum conditions for crystal growth?
Warmth is key to forming crystals, the jar's surroundings should be warm also for optimum crystal growth. Warm air temperature aids water evaporation, causing the crystals to grow more quickly. Crystals will still grow in cooler temperatures, but it will take much longer for the water to evaporate. Crystal growth also requires light as light evaorates water as heat does. The crystals will eventually grow in the dark, but it will take a very long time.
Place approximately 25 g of
potash alum in a beaker (250 ml or bigger) and add approximately 170 ml of hot
water. Stir the mixture until all the crystals have dissolved. The solution may
have a slightly cloudy or milky appearance due to impurities in the technical
grade of alum used.
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 the watch glass or fresh filter
paper and set aside in a cool sheltered place and allow it to stand undisturbed
- filter paper
- hot water
- potash alum
- filter funnel
The next day, observe the
beaker of solution. The bottom should have become covered with a layer of
smallish crystals which formed spontaneously as the solution cooled.
Carefully decant (pour off) the
clear solution above the crystals into a clean beaker and set it aside for
later, leaving the crystals behind in the other beaker.
Let it stand overnight again
and observe the formation of crystals. Alternatively, if nothing has happened,
crystal growth may also be induced by scratching the bottom of the glass beaker
with a glass stirring rod.
From the bed of crystals, one
good symmetrical crystal or group of crystals needs to be selected to act as
the “seed” for your big crystal. Using a spatula or tongs, transfer the selected crystal to the beaker containing the decanted
solution, trying to place it centrally in the beaker.
Take a picture (if possible) of the crystal, preferably close to a ruler so that you can measure its size, and mark the level of the liquid in the beaker. Record the date in your diary. Cover the solution with a loose-fitting paper hat that permits water to evaporate slowly whilst keeping out dust. Allow the solution to stand in a draft free location, not in direct sunlight or near a heater. The aim is to keep the temperature as constant as possible.
-Brief account of how your crystal grew
Over time the crystal will absorb the potash alum and start to grow bigger. The light will evaporate the liquid until soon there will be no more liquid left, for the crystal to use to get bigger.
-Record of the final dimensions of crystal
The shape of my crystal started of as a small ball then at the end it became a pyramid with a base and a pointy top, with four sides.
The photographs demonstrate the properties of crystals as it shows how they grow and absorb the liquid. In the pictures you can also see the light refracting inside the crystal and also reflecting the light.
Cambell, H. (n.d.). Why do different crystals have different shapes and sizes? Retrieved September 2013, from Kiwi Web: www.chemistry.co.nz/crystals_shapes.htm
Crystals. (n.d.). Retrieved October 2013, from Wikipedia: en/Wikipedia.org/Wiki/Crystals
Helmanstine, A. M. (2013). Crystal Chemical. Retrieved October 2013, from About.com Chemistry: chemistry.about.com/od/rowingcrystals/a/Crystal-Chemistry.htm
Helmanstine, A. M. (2013). Types of crystals. Retrieved October 2013, from About.com: chemistry.about.com/cs/growingcrystals/a/aa011104a.htm