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Stories in Stone


Scientific Method

Salt Expirement

Purpose-
To tell the difference between rocks and minerals using the knowledge if it has a crystal structure.

Hypothesis-
We predicted that the water on the metal and plastic spoons and the cups, will evaporate the solution of hot water and salt that we put in it will evaporate and leave salt crystals, or halite deposits.

Materials-

  • 8 cups (so the water won't leak)
  • 2 spoons (we used one metal and one plastic)
  • boiling water
  • table salt
  • stirrers
  • tape
  • a plastic plate
Procedure-
First, you stack up 4 cups into 2 groups, and pour 2/3 of a tablespoon of salt into the cup. Then, fill half the cup with boiling water and stir until the salt is dissolved. Then, tape one of the spoons on on side of the plate and tape the other one on the other side. Fill it up 3/4 or 1/2 of the cup with water.Add a pinch of salt. Wait one day, then observe what has become of the solution of the table salt and the hot water.

Data/Observations-
metal spoon observations
plastic spoon observations
has a crystal structure
has a crystal structure
has bigger crystals than plastic spoon
has smaller crystals than metal spoon
shaped into cubes
faded white color (transparent)

CER-
Our hypothesis was right, the solution that evaporated left salt crystals more informaly known as halite. We knew that it was a mineral becuase it was solid, and it had a cubed crystal structure.

external image Halite%28NaCl%29.JPG
As you can see, the crystal halite is shaped
like a cube, so its crystal structure is a cube.
( picture from http://www.chem.ox.ac.uk/icl/heyes/structure_of_solids/Scans/Halite(NaCl).JPG)





Rock Number
Properties
Prediction
Rock/min
Why
1
rough,solid,shiny
mineral
because there are
other minerals in it
2
rough,solid,shiny
rock
it's cleavage looks
hard
3
split into cracks,shiny
mineral
it cracks easily
4
hard,solid,dull
mineral
it's hard
5
hard,solid,there are
lots of different colors
rock
it has lots of other
minerals in it
6
hard,pointy,smooth
rock
it is hard to break
7
light,shiny,rough
mineral
it is very light
8
rough,hard,solid
rock
it has lots of
minerals in it
9
rough,hard,shells
rock
there are lots of
minerals combined
10
rough,hard,solid
rock
it does not have a
crystal structure
11
rough,hard,solid
rock
it has different
minerals in it
12
smooth,solid
rock
it is hard to break
13
rough,shiny,crystal
structure
mineral
it has a crystal
structure
14
rocky,rough
rock
it has minerals
in it
15
hard,rough,solid
rock
it has minerals
in it
16
smooth,hard
rock
it is hard and solid