Exploring Crystals

Members: Deadtrees, Evergreen7, Hippo44, Blacky, Gongshow,

General areas of interest: Crystals, Chemistry.

Specific areas of interest: How do crystals form? What chemicals are involved in crystal formation? How do different chemicals affect crystal formation?  How do different conditions affect crystal formation?

Background Research and Exploration:

In chemistry, crystals are a type of solid material composed of atoms or groups of atoms that are arranged in a three-dimensional, geometric and repeating pattern. Below are some interesting facts we have learned about crystals.

The Structure of a Crystal

  • Atoms in a crystal are arranged in highly ordered microscopic structure forming a lattice that extends in all directions. A lattice is the actual arrangement of particles in the crystal that is repeated.

    Crystal Lattice: Definition & Structure

  • Crystals can also be categorized by their physical/chemical properties. (Each type of crystal has a different type of bond or connection, between its atoms.) The type of crystal that is formed is determined by the type of atoms and the arrangement of bonds. There are four types of crystals: covalent, ionic, metallic, and molecular.

    KiWi Web: Crystal Types 

How Crystals Form

In order for crystals to form you need a saturated solution.  This means that you have dissolve something like sugar or borax into boiling water until no more can be dissolved.  You use boiling water so that more solute can be dissolved,  When the hot, saturated mixture cools there is more solute (in our experiment this will be borax) than can be contained by the cooler water (this is because in cooler water the water molecules are closer together), and so the borax molecules come out of solution, and collide with  each other.  If you have a seed crystal or something that acts like a seed crystal (a pipe cleaner) the crystals will form around it in a specific repeated pattern as the water continues to cool.

Links to Crystals We Have Made

Question Development:
 We found out that we need boiling water to have a super saturated solution. Now we are wondering what are the best temperature conditions for growing the best crystals. Will crystals grow best at Room Temperature about( 21˚C), in a refrigerator (4˚C), or a warm environment (35˚C).

Hypothesis: 

W e think that borax crystals will crystals grow best at Room Temperature about( 21˚C), in a refrigerator (4˚C), or a warm environment (35˚C).

Procedure: 

  1. Gather equipment ( 400 ml beakers, clothes pins, Sodium Tetraborate (borax), water, pot, pipe cleaners, refrigerator, griddle, metal tray)
  2. Cut twelve pieces of pipe cleaner and tie one around each clothes pin.Once they are tied to the clothes pin cut the pipe cleaner so they are the same length and so they don’t touch the bottom of the jar. Label the jars and clothes pin and weigh them.
  3. Fill a pot with four litres of water.
  4. With adult supervision, bring the water to a boil on a stove.
  5. Add 720 ml of borax to the water, and stir until it dissolves.
  6. Pour 300 ml into each 400 ml beaker. Lay a straw across the top of each jar so the pipe cleaner hangs down into the saturated solution.
  7. Cover the lids with filter paper.
  8. Place three jar in the refrigerator, leave three undisturbed on a countertop or table at room temperature, and put three in a warm environment ..
  9. Leave the jars alone for a minimum of 5 hours, or until crystals form and be sure not to disturb them. Let all of the jars grow their crystals for the same amount of time. Check the warm bath regularly to make sure that it is staying at a constant temperature.
  10. Carefully remove the crystals from the jars and remove the straws. Leave the crystals on a paper towel for around 30 minutes to dry.

Results:

In Hot Water BathWeighing the Beaker and CrystalsOur Results
In Ice BathWeighing jarsIMG_1516
Our Final Results looked like this. Analyzing Data using the Google Suite of Apps including the Spreadsheet and Pivot Tables
IMG_1582IMG_1519
 
Crystal Growth Raw DataCrystal Growth Average
Crystal Raw DataCrystal Average Chart
Pipe Cleaner CrystalsTotal Crystal Results
Pipe CleanerTotal
Conclusions:
In the end, all three temperatures formed crystals but the best temperature for forming high-quality crystals is room temperature. Although the fridge solutions formed more crystals than room temperature, they were smaller, more clumpy, and not clear or shiny (foggy). The room temperature formed better looking, larger, more cube-like crystals. Warm bath was the worst temperature for forming crystals. It did have some, but they weren’t completely formed and they were not as big or as cube-like. The best temperature for forming crystals is room temperature.
Comment: This is a great start to your conclusions but I would expand on why you think the cold temperature caused crystals to form faster but were a lower quality?
Thanks Matt  we added what we found out 🙂
Further Research:
After researching further we found out why crystal form best at room temperature. When recrystalization occurs in a saturated solution there are always impurities. The impurities, however are rejected because they do not fit well with the structure.  They will  remain in the water.  If a solution is cold like the solution we put in the fridge, the impurities do not have time to be rejected by the structure and become trapped, deforming the crystal.  The pattern is disturbed and the result is a clumpy, less cube-like crystal.