Lab: Sludge Test


Having collected samples from the spaceship wreck, your final mission is to demonstrate the skills and knowledge you have acquired in HoPS by successfully separating a mixture of solids and liquids (sludge) and identifying the pure substances contained in the mixture using their characteristic properties.


The sludge test will be a major part of your grade (~25%) as well as being the CIM Performance Task in 9th grade science.  It is important that you understand and abide by the following rules:


1.  Your lab team will adopt a unique jar of sludge from the spaceship.  Guard it with your life!  There

      is no way to return to the planet for more---the planet is gone...

2.  Since each lab team is responsible for an individual solution, communication should be limited to team

     members and the teacher.  If other groups can hear your conversations, you are speaking too loudly.


3.  Storage of sludge products will be limited to film canisters, your original baby food jar and a

     shoebox.  However, you may bring other containers or storage bags from home, if desired.

4.  Clean-up is to be done before the bell.  (No late passes!) This includes your lab bench, sink and equipment,

     as well as class areas and equipment.  If public areas (counters, sinks, equipment) are left messy, it is possible

     for the entire class to lose points.  It is important to return clean equipment to their original storage

     areas, not to the sink or counter.

5.  Students may come in alone before/after school to make-up absences; however, all team members

     must be present if extra time is needed on test.


Grading:  Note:  I use a mathematical equalizing formula to correct for different numbers of substances. 


1.  Daily Log - A daily log must be kept showing a daily plan, the procedure followed, observations

     and data, and general results.  It can also be used to reflect on your daily successes and failures. 

     Your log from the previous day will be checked during each lab and a score of 1-6 given for the

     previous day's entries.  If your lab is incomplete or elsewhere, your daily score will reflect your lack

     of planning. (24 pts possible)

2.  Separation - Each sludge will contain from 4-12 substances.  There may also be one or two agents

     of disguise added to mask colors and/or odors.  It is not necessary to separate or identify the agents

     of disguise, just note its presence.  For each substance that is successfully separated and shown to the teacher

     you will earn 6 points.  (48 pts possible)

3.  Characteristic Properties - Characteristic properties must be determined for each substance that is

     separated.  Some properties will be required (2 pts each, if correct); others will be optional (1 pt

     each, if corrected) up to a maximum of 12 points for each substance. 

4.  Identification - For every substance you correctly identify (with at least three supporting pieces of

     evidence), you will receive 6 points. (48 pts possible)

5.  Participation - It is important that each member of the team participates.  Each team member may

     earn 6 participation points per day.  This will be decided by the team members each day.  If a team

     member is absent, daily participation points are not awarded.  However, these points may still be

     earned if the absence is made up before or after school in a single hour session or two 30-minute

     sessions.  If tasks have been completed, there is no way to make up participation points.  (24 pts possible)

6.  Lab Safety and Clean-Up - After each class your lab area and equipment will be checked for proper

     clean-up and storage.  You will be monitored during class for proper safety procedures.  Each student 

     will earn 6 points per day for correct clean-up and safety practices.  A minor safety infraction will 

     result in the loss of 1 points, a second will result in a loss of 3 points and a third will result in the

     loss of 6 points and may result in removal from the lab and the chance to complete or get credit for the sludge

     test.  SAFETY FIRST!  (24 pts possible)

7.  Lab Write-Up - Each part of the write-up is worth points as shown on reverse side.  In addition, the

     quality of your lab write-up will be graded as follows: conventions - 6 points, neatness and clarity -

     6 points, organization - 6 points, and completeness - 6 points.  (24 pts possible) 



Final Lab Report for Sludge Test


The lab report, an accumulation of 5-6 hours of lab work, will be graded on a point system with extra credit given for extra effort and creativity.  It should be written neatly in ink or typed on one side of the paper and should be organized as follows:  (Maximum points possible indicated)


1.  Cover Page - with Title, Lab Partners names, Class Period, Date and Sludge Jar Number (6 pts)

2.  Problem  - (Re:  Ask a Testable Question!)  (6 pts)

3.  Hypothesis - On Day 1, just observing your sludge, what did you think you might have collected from

     extinguished planet?  (6 pts)

4.  Procedure  - Flowchart of the methods of separation and identification used during the experiment. (12 pts)

5.  Data - Use tables when possible  (Be sure to include sludge number)  Note:  X is required!

     a.  Observations [appearance (X) & odor (X)]  --- Note:  this may be included in Characteristic Properties Table                                               

     b.  Separate tables for:                     

              i.  Densities (example #1 below) (6 points)

             ii.  Characteristic Properties (example #2 below)  (6 points)                 

            iii.  Solubilities (example #3 below) - optional  (6 points)

#1   Density Table


Insoluble Solids

Soluble Solids







Mass of container and substance (g)






Mass of container (g)






Mass of substance (g)






Volume of substance (cm3/ml)






Density of substance (g/cm3)







#2  Characteristic Properties Table


Insoluble Solids

Soluble Solids







Flammability (Yes/No)






Boiling Point (°C)






Note:  all other properties optional







#3 Solubility Table


Insoluble Solids

Soluble Solids







Liquids Dissolve:












     Note:  all other solids optional






Solubility of Solids in:












     Note:  all other liquids optional







    c.  Calculations:  Show one labeled example of every type of calculation used in density. (6 pts)

    d.  Graphs (2)

             i.  Boiling point graph of original mixture of liquids (12 pts)

            ii.  Boiling point graph of each pure liquid on one axis (overlay) (18 pts)

           iii.  Analysis of each graph---"What is each graph showing you?"

6.  Conclusion - In paragraph, restate purpose & hypothesis.  Summarize make-up of original mixture including

     number and names of liquids, insoluble solids and soluble solids.  For each substance identified, give at least

     three specific pieces of evidence from experiment to support your identification.  ["The density was 2.48 g/cm3, and

     the density of quartz is 2.6 g/cm3," instead of "we found the density" or "the density matched quartz"] (12 pts)

7.  Analysis - List at least three possible errors that occurred during the experiment and discuss possible solutions if you

     were to redo the experiment---how did errors affect your results? (12 pts)

8.  Reflection - Attach a one-page reflection on your experience with the Sludge Test and your effort and

     contribution as a team member.  This is the appropriate place to "vent/share" your feelings about how much

     you did/didn't enjoy the experience, how much you did/didn't learn, etc...  A reflection is about you, not your

     partner---good or bad.  (12 pts)

9.  Daily Log - Arrange daily log chronologically and attach in toto to end of lab write-up.  Do not rewrite (just

     in case you become famous, like Leonardo da Vinci); your report is the "rewrite".  (24 pts)