Mrs. Whalen’s Hints to Ace the CAPT Lab

1.      Bring a pencil, eraser and a calculator. 

2.      Write neatly.  Both you and the grader need to be able to read this.  Sloppy work puts off the grader, and he/she may not be able to read something important.

3.      Listen carefully when the instructions are read to you.  Ask questions then.

4.      Determine the independent and dependent variables first!  Don’t try to write the problem statement first.  VARIABLES MUST BE MEASUREABLE!!!!  Rate is not measureable, nor is speed.
Independent variable:      This is what you change.
Dependent variable:        Changes in response to your adjustments (independent variables).  The measured outcomes.

5.      Then figure out what will remain constant in your experiment.
Constant:    What parameters will remain the same through all your tests.

6.      Determine whether there is a control for this experiment.
Control:      A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed.

7.      Now write the problem statement.  Remember – it is usually stated as a question.  For example: How does the (independent variable) affect the (dependent variable)?

8.      You are ready to write the Procedure (or Experimental Design).  List the steps it will take to perform the experiment. Develop numbered steps (1,2,3) so that anyone reading it may exactly duplicate the experiment.  Remember this is your draft – if you need to adjust it for the final version you can.  A control should be included when appropriate.

SOME IMPORTANT POINTERS: 

a)   Remember liquids need to be measured by volume in a graduated cylinder (NOT A BEAKER).

b)   Solids are usually measured by mass (grams) not by spoonfuls, scoops, pinches.

c)  Always make sure you measure your variables – temperature, volume, mass, etc.  Don’t just assume your have 100 ° C water because it is boiling.  Measure it!

d)  Remember to include multiple trials of each experiment.  This reduces your error.

9.      Record all data in a data table.  Remember to include your units of measure (grams, seconds, mL, etc.).  There should be at least one column for each variable.

10.  CAPT Labs usually require a graph.  You must work alone on this.  REMEMBER:  A line graph is used when you have numbers and numbers.  A bar graph is used when you have words and numbers.

SOME IMPORTANT POINTERS: 

a)   Independent variable goes on the X axis (horizontal).

b)   Dependent variable goes on the Y axis (vertical).

c)   Label each axis and include your units of measure.  Title the graph.

d)   Always use graph paper, not lined paper.

11.  Finally, tackle the CONCLUSION.  This is extremely important.  It is a statement of what has been found in this experiment, which is directly related to the problem, and supported by the data.  Refer specifically to the data.  Then include a discussion of the experiment’s validity (error analysis).
Error Analysis     
-What was done to reduce the possibility of errors?
-What errors (in the design of the experiment) possibly could have occurred?
-If these errors occurred, would it be likely to impact the interpretation of the results?
-Should this experiment be repeated and how could it be improved? 

12.  If there are 2 experiments in the CAPT lab – the independent variable in the first experiment usually becomes a control in the second one.