Grades 912 Performance Task
Contributed by: New York State Education Department (NYSED)
Developed through University of Buffalo and NORC (1991)
Part A  Experiment Design
Introduction:
This laboratory test presents a problem. Your task
in Part A is to plan and design an experiment to solve the problem.
You will have 30 minutes to complete Part A. At the end
of the 30 minutes, your answer sheet will be collected. You will
then receive separate directions for Part B. In Part B you will
use materials and equipment provided in the laboratory kit to
collect experimental data for this problem. You may wish to do
your preliminary planning on the sheet labelled "Working
Copy." Write this plan on the appropriate answer sheet in
your test booklet.
Problem:
Diffusion is a process by which substances enter and
leave cells. Your problem is to design an experiment to
test the effects of two variables (time and concentration)
on diffusion of potassium permanganate into potato cubes.

a) State a HYPOTHESIS for this investigation that
can be used to test the effects of time and concentration on diffusion.
b) Under the heading PROCEDURE list in order the
steps you will use to solve the problem. You may include a diagram
to help illustrate your plans for the experiment. Include any
safety procedures you would follow.
c) Construct a DATA TABLE or indicate any other
method that you could use to record the observations and results
that will be obtained.
PLEASE NOTE: In Part A you are NOT to proceed
with any part of the actual experiment. You are just to plan and
organize a way to investigate the problem.
Materials:
 2 firm potatoes
 Metric ruler (30 cm)
 3 small beakers (approx. 150 ml)
 1%, 5%, and 10% solutions of potassium permanganate (in beakers)
 Forceps
 Scalpel
 Stopwatch/clock
 Paper towels
 Experiment Display Sheet
 Waste container
 Graph paper
WORKING COPY
PART A  Experiment Design
This sheet is provided as a work space (or scrap
sheet).
Be sure to enter your final plan on the appropriate answer sheets.
No work on this sheet will be considered for credit.
ANSWER SHEET
PART A  Experiment Design
Organize your experiment design under the following
headings:
HYPOTHESIS, PROCEDURE, and DATA TABLE.
Use the front and back of these sheets if necessary.
HYPOTHESIS
PROCEDURE (Include diagram if appropriate)
DATA TABLE (For results and observations)
Part B  Experiment Report
You will have 50 minutes to complete this part.
Record your work for Part B on the answer sheet under the appropriate
headings. Perform the experiment by following the steps outlined
in the procedure (listed below). Under the heading RESULTS record
your observations and measurements for the experiment. Use written
statements, descriptive paragraphs, tables of data, and/or graphs
where appropriate. Construct a GRAPH which presents the relationship
between the distance of diffusion into the potatoes and time and
concentration. Under the heading CONCLUSIONS write an interpretation
of your results. State the effect that time and concentration have
on diffusion.
At the end of 50 minutes, your answer sheet for Part
B will be collected.
Safety
CAUTION: SLICE AWAY FROM FINGERS TO
AVOID CUTS.
HANDLE POTATO CUBES WITH FORCEPS ONLY.

Procedure:
 Using a scalpel, cut 12 cubes from a potato. Each side of the
cubes should measure approximately 1 cm. Be sure that there is
no skin on anyof the cubes.
CAUTION: SLICE AWAY FROM FINGERS
TO AVOID CUTS.
HANDLE POTATO CUBES WITH FORCEPS ONLY.

 Place 4 potato cubes in each of the three beakers of different
concentrations of potassium permanganate. Note the exact time
the cubes were added to the solutions.
 With forceps, remove one cube from each solution every 5 minutes
and place on a paper tower. Slice each cube in half with a scalpel.
CAREFULLY dry the scalpel before slicing each cube.
 Remove the Experiment Display Sheet from the back of the test
booklet. Measure and record the distance that the solution has
diffused into each potato for each time interval. After measuring,
place the cubes on the Experiment Display Sheet for later checking
of results or verifying conclusions.
 Record the RESULTS of your experiment in the data table. Enter
the distances for each concentration and time.
 Construct a GRAPH for these results.
 Based on your data table and graphing of the results, state
your CONCLUSIONS as to how the length of time in solution and
the concentration of the solution influence the distance of he
diffusion.
When you are finished with all work, discard the potato cubes
in a container labelled "WASTE."
ANSWER SHEET
PART B  Experiment Report
Organize your experiment report under the following
headings:
RESULTS, GRAPH, and CONCLUSIONS.
Use the front and back of these sheets if necessary.
RESULTS

Distance of diffusion
(in mm)

Distance of diffusion
(in mm)

Distance of diffusion
(in mm)

Concentration of potassium permanganate

After 5 minutes

After 10 minutes

After 20 minutes

1%




5%




10%




Construct your GRAPH on the graph paper provided.
CONCLUSIONS
