Transcript What is a Scientist? - Cockeysville Middle School

Objective: To utilize the skills and processes
of science in order to identify an
unknown substance.
CSI Note: How can the unknown substance be
identified?
Drill:
1. Get a Lesson Sheet from the SET.
2. Complete the Drill portion only in your
log book.
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Identify as many characteristic
properties as you can think of.
Density
Color
Taste
Boiling Point
Solubility
Magnetism
Freezing Point
Hardness
Conductivity
Think about what properties we can
explore in class.
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Look at the possible tests/measurements
that can be made on the unknown in a
laboratory situation. Tell which tests you
can/should explore. Justify your
selections.
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Density
Yes
It is a characteristic property.
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Taste
No
It is a characteristic property, but
it is unsafe to taste unknown
substances.
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Color
Yes
It is a characteristic property.
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Boiling Point
No
It is a characteristic property, but
we do not achieve the
temperatures necessary to do
this..
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Shape
No
It is not a characteristic property.
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Solubility
Yes
It is a characteristic property.
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Magnetism
Yes
It is a characteristic property.
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Mass
Yes
It is a not a characteristic
property, but it is necessary to
calculate the density.
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Volume
Yes
It is not a characteristic property,
but it is necessary to calculate
the density.
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Conduct the Investigation
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Materials:
Unknown substance
Graduated cylinder
Paper towels
Triple beam balance
Magnet
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Calculator
Ruler
Paper cup
Water
Spoon
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Procedures:
Color
1. Observe the mystery substance.
2. Enter the color into the data chart.
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Procedures:
Density
1. Zero the triple beam balance.
2. Place the solid on the triple beam balance, and
determine its mass.
3. Record the mass in the data chart.
4. Using a cup, add between 30mL and 60mL of
water to the graduated cylinder.
5. Record the volume of water in the Volume Side
Chart as your starting volume.
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Procedures:
6. Carefully slide the substance into the
graduated cylinder.
7. Record the total volume in the Volume Side
Chart.
8. Calculate the volume of the substance by
subtracting the starting volume from the total
volume.
9. Record the volume of the substance in the
Volume Side Chart.
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Procedures:
10. Calculate the density of the object by
dividing the mass by the volume.
11. Record the density in the data chart.
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Procedures:
Magnetism
1. Dry off the substance.
2. Touch the magnet to the substance and
observe the reaction.
3. Record the reaction in the data chart.
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Procedures:
Solubility
1. Fill a cup halfway with water.
2. Carefully place the substance into the water.
3. Stir the substance with a spoon.
4. Record the reaction in the data chart.
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ANALYSIS
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Examine Chart 1, “Unknown Possibilities”. It provides a
list of the suspects and the characteristic property that
they leave behind. It also provides key characteristic
properties for each substance.
Unknown Possibilities
Suspect
Substance
Color
Boiling
Pt (oC)
Solubility
In Water
Density
(g/mL)
Magnetic
Yes/No
Slick Nick
Nickel
Silver
2914
NO
8.9
YES
Al Foil
Aluminum
Silver
2467
NO
2.7
NO
Sylvia
Shine
Silver
Silver
2163
NO
10.5
NO
Cupric
Carl
Copper
reddish
2563
NO
8.96
NO
So Shady
Sodium
Silver
883
YES
0.97
NO
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Compare the results from the
examination of your mystery
substance with the substances in
the chart. Check off the
characteristics that match your
substance.
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What substance do you think you
discovered?
Who do you think committed the
crime? Why?
(It is possible that you can’t yet
identify the mystery substance, and
that you no longer have any suspects.)
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