Day 7

1
Day 7
Explain why this is true When a metamorphic
rock is forming, it may be subjected to extremely
high temperatures, yet it never completely melts.
(Hint What would the rock be if it completely
melted?)
Because if it melts, it would become molten rock.
If it then cools and hardens, it would be an
igneous rock.
Daily Warm-Up Exercises
2
Salol Crystals (Part 1, steps 1-10)

• Investigation 8
• One Rock to Another

3
Intrusive Extrusive Rocks

• Examine your igneous rocks with a hand lens.
• Look for crystals (pieces of pure minerals) in
  the rocks.
• Sort into intrusive and extrusive.

4
Intrusive Extrusive Rocks

• Is there a relationship between crystal size and
  whether the igneous rock was intrusive or
  extrusive?

• Intrusive rocks like granite have larger
  crystals.
• Obsidian doesnt appear to have any crystals.

Why do some igneous rocks have larger crystals
than others?
5
Salol

• Rocks must reach 750 0C (1382 0F) or more before
  they will begin to melt.
• We cant melt rocks in class, but we will use
  Salol to simulate the melting and cooling of a
  rock.
• Salol melts at the temperature of hot tap water.

6
Crystal Size Investigation
Use lab pages 77-79. Design an experiment using
salol to answer the following questions

• What variable do you think will affect the size
  of the crystals that form?
• What effect will this variable have on crystal
  size?

7
Variables

• What are some of the variables that might affect
  the size of the crystals that form?

• Temperature
• Rate of cooling
• Length of time in hot water
• The way the bottle lies as it cools
• Create a data table to represent both
  variables that you are testing.

8
Procedure

• Work as a group. Get two bottles of salol.
• Place the two bottles of salol in the hot water
  to melt.
• Place one bottle on its side in the container of
  ice water. Place the other bottle on its side in
  the room temperature water.
• Observe and record every 30 seconds.
• Compare the crystals in the two bottles when all
  the material has crystallized.

9
Data Table
Controlled Variable (Room Temperature) Manipulated Variable (Ex Cold Water, Lying Flat)
Elapsed Time Observations Elapsed Time Observations
0 sec liquid 0 sec liquid
30 sec 30 sec
60 sec 60 sec
90 sec 90 sec
120 sec 120 sec
150 sec 150 sec
Continue on lab Continue on lab
9
10
Observations Draw what you see
Controlled Variable (Room Temperature) Manipulated Variable (Ex Cold Water, Lying Flat)
10
Include measurements w/ units!
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Discuss What Happened

• What happened when you placed the salol in the
  cold water?
• it hardened and turned back into crystals
• What do the crystals look like?
• some look like crushed ice or big sugar
  crystals others look like flat needles or
  feathery branches some grow in rosettes from a
  central point or circle

12
Crystallization

• Forming crystals is called crystallization.
• Crystal shape is one of the properties geologists
  use to help them identify minerals.
• Salol crystals form the same shapes each time
  they crystallize (needles feathers diamonds
  broken ice).

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Materials for Salol Lab

• Each pair needs
• lab sheet
• one bottle of Salol
• THE BOTTLES MUST STAY CLOSED
• Each group needs
• hot and cold water

14
Stop Here
15
Melting Temperature

• How can we find out the temperature at which
  salol melts?
• Salol melts at around 40 0C.
• If the temperature drops below 40 0C, the salol
  will begin to crystallize.

put the bottle in different temperatures of water
and find the lowest temperature at which it will
melt
16
Observe Salol Melting

• Turn to a new page in your notebook.
• Title your page
• Salol Observations

17
Discuss What Happened

• What did the salol look like before you placed it
  in hot water?
• white crystals on the side of the bottle
• How long did it take for the salol to melt?
• about 1 minute

18
Review
Day 6 Information
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Labels
Exercise 8.4
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Naming Labels
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Naming Labels and Explanatory Labels
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Captions
Exercise 8.5
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CaSE Book Student Rescource Book, Page 23
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Without a caption, it is difficult to know much
about this image
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With the caption in place, the viewer has the
necessary information.
As magma cools, different minerals come together
toform crystals, as in this granite. The
crystals growtogether, filling the spaces.