Mystery Powder Lab
Someone has fallen ill at a restaurant! They were found to have a white powder on them, which could either be the cause of their illness, or be a harmless cooking ingredient. In pairs, you will compare the physical and chemical properties of the unknown powder to the five known powders found in the restaurant to determine the identity of the unknown powder.
Step 1: Scoop a small amount of power in four wells
Step 2: Add your ‘indicators’ to each cup and stir with a toothpick
Well 1 = 1 drop of water, Well2 = 1 drop of vinegar, Well 3 = 1 drop of iodine, Well 4 = 1 drop of universal indicator
Step 3: Record the results of your tests (yes/no reaction, what happened?) on the data table
CRITERION / LEVEL 1 / LEVEL 2 / LEVEL 3 / LEVEL 4Purpose
/5 / Purpose is identified in a limited way / Purpose is identified with some errors / Purpose is identified with only minor errors / Purpose is clearly and appropriately identified
Hypothesis
/5 / Statements have some relevance but do not deal with the testable aspects of the investigation / Statements have much relevance but deal with some of the testable aspects of the investigation / Statements have much relevance and deal with most of the testable aspects of the investigation / Statements are very relevant and deal with all of the testable aspects of the investigation
Apparatus
/5 / Lists and/or diagrams are missing many relevant materials / Lists and/or diagrams missing some relevant materials / Lists and/or diagrams are complete with most relevant materials / Lists and/or diagrams and thorough and complete
Method
/10 / Design allows for limited testing to obtain meaningful data.
Design is unclear and lacks organization – not easily repeatable / Design allows for some testing to obtain meaningful data.
Design is somewhat unclear and lacks some organization – repeatable / Design allows for sufficient testing to obtain meaningful data.
Design is mostly clear and organized into numbered statements – repeatable. / Design allows for more than sufficient testing to obtain meaningful data.
Design is clear and organized into numbered statements – easily repeatable.
Observations
/10 / Data are recorded but contain many error and/or omissions.
Tables/charts are present but require much organization. / Data are recorded but contain some error and/or omissions.
Tables/charts are present but some organization. / Data are recorded but contain 1 or 2 errors and/or omissions.
Tables/charts are present but require only a little organization. / Data are recorded but contain no errors and/or omissions.
Tables/charts are present, thorough and well organized.
Discussion
/15 / Conclusions are relevant but contain many inaccuracies and/or omissions.
Conclusions show limited understanding of concepts/principles involved. / Conclusions are relevant but contain some inaccuracies and/or omissions.
Conclusions show some understanding of concepts/principles involved. / Conclusions are relevant but contain 1 or 2 inaccuracies and/or omissions.
Conclusions show considerable understanding of concepts/principles involved / Conclusions are relevant, accurate and thorough.
Conclusions show thorough understanding of concepts/principles involved
Analysis Question (To put in your discussion!):
1. Identify any evidence of chemical changes in each test.
2. Use the evidence provided by the tests to identify the mystery powder
3. Which properties, physical or chemical, were most useful in identifying the mystery powder?
4. How confident do you feel about your identification of the sample? What improvements would you suggest for similar investigations in the future?
5. You find a puddle of clear, colourless liquid on your driveway. It is either water, vinegar, or spilled battery acid from the car. How can you safely test the liquid to determine its identity? Explain how you can interpret your observations.
OBSERVATION TABLE FOR MYSTERY POWDER LAB
Powder / Physical Properties / Water / Vinegar / Iodine / Universal IndicatorAspirin
Baking Soda
Baking Powder
Corn Starch
Icing Sugar
Mystery Powder