2012
Internal Assessment Resource
Subject Reference: Biology 2.1
Internal assessment resource reference number:
91153
Making Chips
Supports internal assessment for:
Achievement Standard 91153 v1
Carry out a practical investigation in a biology context with
supervision.
Credits: 4
Date version published:
November 2011
Ministry of Education
quality assurance status
For use in internal assessment
from 2012
Authenticity of evidence
Teachers must manage authenticity for any assessment
from a public source, because students may have
access to the assessment schedule or student exemplar
material.
Using this assessment resource without modification
may mean that students’ work is not authentic. The
teacher may need to change figures, measurements or
data sources or set a different context or topic to be
investigated or a different text to read or perform.
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Teacher Guidelines:
The following guidelines are supplied to enable teachers to carry out valid and consistent
assessment using this internal assessment resource. Teachers need to be very familiar with
the outcome being assessed by Achievement Standard Biology 91153. The achievement
criteria and the explanatory notes contain information, definitions, and requirements that are
crucial when interpreting the standard and assessing students against it.
Context/setting:
This activity requires students to plan and carry out a fair test investigation into the effect of
osmosis on potato cell tissue. It therefore involves the manipulation of a variable (fair test:
EN 5).
It is suggested that this assessment activity will take place over 5 class periods. Adjust this
to suit your students and context.
Students will plan their investigation individually, and submit their plan for feedback.
Students may make changes to their initial method as they work through the investigation
(EN 3). The teacher will pair the students, based on their plans. Students modify their plan
and collect their data in pairs, but process and report on their data individually.
Conditions
It is suggested that this assessment activity will take place over 5 class periods. Adjust this
to suit your students and context.
Students will plan their investigation individually, and submit their plan for feedback.
Students may make changes to their initial method as they work through the investigation
(EN 3). The teacher will pair the students, based on their plans. Students modify their plan
and collect their data in pairs, but process and report on their data individually.
Resource requirements
The teacher will need to provide students with:
Potatoes, knives (or cork borer), distilled water, weighing balance, containers, lids,
gladwrap, paper towels, a range of sugar solutions (0.1 mol L -1, 0.2 mol L-1, 0.3 mol
L-1, 0.4 mol L-1, 0.5 mol L-1, 0.6 mol L-1, 0.7 mol L-1, 0.8 mol L-1, 0.9 mol L-1), normal
lab equipment e.g. measuring cylinders.
Sugar solutions can be made up as follows:
0.1 mol L-1 = 3.4 g sucrose in 100 ml water
0.2 mol L-1 = 6.8 g sucrose in 100 ml water
0.3 mol L-1 = 10.3 g sucrose in 100 ml water
0.4 mol L-1 = 13.6 g sucrose in 100 ml water
0.5 mol L-1 = 17.1 g sucrose in 100 ml water
0.6 mol L-1 = 20.5 g sucrose in 100 ml water
0.7 mol L-1 = 23.9 g sucrose in 100 ml water
0.8 mol L-1 = 27.3 g sucrose in 100 ml water
0.9 mol L-1 = 30.8 g sucrose in 100 ml water
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Additional information:
It is expected that students will have carried out a similar investigation and have
practised the use of the processing and graphing techniques appropriate to this
investigation. Therefore students will be familiar with the need to use % mass
change instead of actual mass change.
To gain merit and excellence students need to discuss and evaluate the
investigation. In the discussion they need to show understanding of how and why
osmosis occurs and be able to relate this to their results by discussing what their
results (i.e. gain of mass and loss of mass) show. In the evaluation they must show
understanding by discussing how they ensured that the method they used was valid
and reliable i.e. how sources of errors were minimised, limitations overcome, how
bias (the lack of objectivity when carrying out the investigation) was removed and
how they know they gathered sufficient data.
Salt solutions could be substituted for sugar solutions. Carrots could be used instead
of potatoes.
Provide resource materials covering the essential biology needed for the activity, such as:
photosynthesis, the electromagnetic spectrum, wavelengths for each colour, information
about leaf pigments and their function.
The investigation is carried out with supervision (EN 6). This means that the teacher
provides guidelines for the investigation such as the context for the investigation, instructions
that specify the requirements for a comprehensive investigation, and broad experimental
conditions such as the availability of equipment or chemicals.
Further information about the Conditions of Assessment related to this achievement
standard can be found at www.tki.org.nz/e/community/ncea/conditions-assessment.php.
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Internal Assessment Resource
Achievement Standard Biology 91153: Carry out a practical investigation
in a biology context, with supervision
Resource reference: Biology 2.1
Resource title: Making Chips
Credits: 4
Achievement
Achievement with Merit
Carry out a practical
investigation in a biology
context, with supervision.
Carry out an in-depth
practical investigation in a
biology context, with
supervision.
Achievement with
Excellence
Carry out a comprehensive
practical investigation in a
biology context, with
supervision.
Student instructions
Introduction
This assessment activity requires you to produce a Biological Report on the presence or absence of a
relationship into the process of osmosis using potato chips soaked in different sugar solutions.
As part of the assessment you are required to:

individually plan your investigation and submit your plan to your teacher for feedback

process and interpret your data and report on the investigation individually

interpret your findings with relation to another source, after considering and comparing
them with the whole class or findings from scientists relevant to photosynthesis.
You will have access to your portfolio of biological ideas and concepts learned during the
teaching of the topic as you write your report.
You have 4–5 class periods to complete this investigation.
A possible time frame could be:
Period 1
Develop and trial a method
Period 2–3
Carry out investigation to collect data
Period 4-5
Process data / complete Biological Report.
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Students are to work in groups to collect their data (EN 4). Group work is acceptable for
collecting data.
You will be assessed on your ability to carry out a complete, valid and comprehensive fair test
investigation, as documented in your report. This includes planning the investigation, collecting,
recording, processing and interpreting the data.
Task
Plan your investigation
Note: You have one period of class time to complete this individually.
Based on your knowledge of osmosis, and the resource material provided, develop a method to
investigate osmosis in potatoes when submerged in different concentrations of sugar.
The following equipment is available:
Potatoes, knife (or cork borer), distilled water, weighing balance, containers, lids,
gladwrap, paper towels, a range of sugar solutions (0.1 mol L -1, 0.2 mol L-1,
0.3 mol L-1, 0.4 mol L-1, 0.5 mol L-1, 0.6 mol L-1, 0.7 mol L-1, 0.8 mol L-1, 0.9 mol L-1).
Normal lab equipment is also available.
Complete your draft plan, it should include:
A purpose for your investigation, written as a hypothesis linked to osmosis.
A detailed step by step method on how to collect your data by considering:
 the range over which the independent variable will be changed
 how the dependent variable will be measured
 how you will control or measure other variables or factors that could have a significant
impact on your investigation
 how you will ensure your results are accurate, valid and reliable
Hand in your plan in to your teacher for feedback.
Write your group plan
Based on your individual plans, your teacher will put you into groups to collect your data.
Discuss your individual plans and decide on a shared plan.
Write and submit your group plan for feedback.
Trial your investigation method, then use the information you found out in your trial to develop it
into a step by step method. Write out your final method in your Biological Report.
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Collect and record your data
Note: You have 2 periods of class time to complete this.
In your assigned groups, collect and record your data. While the group may work together to
collect the data, you must each record your own data.
Record data and observations relevant to your investigation in an appropriate way.
You may amend your method as you carry out your investigation. Make sure you record all of
these changes.
Process your data and report your findings
Note: You have 1 – 2 periods of class time to complete this individually.
Process your data to produce results that can be compared directly with each other i.e. to
enable a trend or pattern (or absence) to be determined, and with other sources of information.
Graph the processed data in a way that allows you to interpret whether there is a trend in the
data.
Use the processed data, observations and measurements you recorded to write a wellorganised a Biological Report on your findings that includes:

a statement of the purpose of your investigation written as a hypothesis linked to
osmosis

a detailed account of the final step by step method you used

recorded data and observations

processed data presented in a table and graph appropriate to the type of data collected

description of the presence or absence of a trend based on the processed data relevant
to the hypothesis. This forms your conclusion.

relevant findings from another source that you can compare with your data and
conclusion

discussion of the reasons for the presence or absence of a trend using the biological
ideas relating to the investigation, based on your findings and those from other source(s)

an evaluation of the investigation, which considers the reliability of the data, and the
validity of the method. For example how sources of error, limitations or bias were
eliminated or minimised.
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Assessment schedule: Bio/2/1 - Making Chips
To be awarded the grade (A, M or E) the student must meet the holistic judgement statement at the top of
the column.
Achieved
Achieved with Merit
The student is able to carry out and
present a report for a practical
investigation on osmosis in potato
when it is exposed to different sugar
solutions.
. The student is able to carry out and
present a report for an in-depth
practical investigation on osmosis
on potato when it is exposed to
different sugar solutions.
The report includes:
The report includes:
Purpose written as a hypothesis
linked to osmosis.
Purpose written as an hypothesis
linked to osmosis.
Final method includes a description
of the
 Independent variable - range of
at least four points, with units of
measurement
 Dependent variable, with units
Control of some (i.e. at least two)
other variables
Final method includes a description of
the
 Independent variable – valid
range of at least four points,
with repeats, units of
measurement
 Valid measurement of the
dependent variable, with units
 Control of most other variables
Collecting, recording and processing of
data to enable a trend or pattern (or
absence) to be determined
 Data processed accurately as
a table, or graph or calculation
of averages
Collecting, recording and processing
of data relevant to the purpose
 Data processed as a table, or
graph or calculation of averages
 Minor processing errors ignored
Reporting on the findings
 Conclusion reached based on
the processed data in relation
to the hypothesis of the
investigation
 Identifies and includes
relevant findings from another
source.
Reporting on the findings
 Valid conclusion reached
based on the processed data
in relation to the hypothesis of
the investigation
 Discussion of the biological
ideas relating to the
investigation based on the
findings and those from other
source(s).
Achieved with Excellence
The student is able to carry out
and present a report for a
comprehensive practical
investigation on osmosis in
potato when it is exposed to
different sugar solutions.
The report includes:
Purpose written as an hypothesis
linked to osmosis.
Final method includes a description
of the
 Independent variable –
valid range of at least four
points, with repeats, units of
measurement
 Valid measurement of the
dependent variable, with
units
 Control of most other
variables
Collecting, recording and processing
of data to enable a trend or pattern
(or absence) to be determined
 Data processed accurately
as a table, or graph or
calculation of averages
Reporting on the findings
 Valid conclusion reached
based on the processed
data in relation to the
hypothesis of the
investigation
 Discussion of the biological
ideas relating to the
investigation based on the
findings and those from
other source(s).
AND


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Justifies the choices made
during the in-depth
investigation by evaluating
the validity of the method or
reliability of the data
Explains the conclusion in
terms of the biology ideas
relevant to the investigation.
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For example:
“More bubbles of oxygen are
produced by photosynthesis when
Elodea is exposed to longer
wavelengths of light,
The student plans and describes a
method that includes the independent
variable (e.g. different coloured filters
to provide a range of at least four
wavelengths, either without repeats,
or all within 200nm of each other), a
dependent variable (e.g. number of
oxygen bubbles released, and control
or measurement of at least two other
variables / factors (e.g. same light
intensity, same distance from elodea
to light source, same period of time in
each light condition before starting
recording, same water temperature,
same sized sample of elodea).
The student collects and records data
relevant to the purpose, e.g. number
of oxygen bubbles released over 5
minutes for each wavelength.
The student processes data relevant
to the purpose, e.g. as a table or a
calculation of averages or a graph of
bubbles produced at different
wavelengths, with minor processing
errors.
The student interprets the processed
data relevant to the purpose and
describes the presence or absence of
a trend as a fair representation of the
data, draws a conclusion based on
the processed data.
The student identifies a biological
idea from the resource materials or
other source(s) that may have
resulted in the trend or absence of
trend.
(Note: The above ‘expected
student responses’ are indicative
only and relate to part of what is
required. Annotated, complete
reports in context that come from
previous/current students or
developed by teachers can be
included as examples of evidence.)
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For example:
For example:
“More bubbles of oxygen are produced
by photosynthesis when Elodea is
exposed to longer wavelengths of light,
“More bubbles of oxygen are
produced by photosynthesis when
Elodea is exposed to longer
wavelengths of light,
The student plans and describes a
method that includes a valid range of
the independent variable (e.g. different
coloured filters to provide a range of at
least four wavelengths, with repeats,
within 200nm of each other), a valid
measurement of the dependent
variable (e.g. number of oxygen
bubbles released, and control or
measurement of most other variables /
factors (e.g. same light intensity, same
distance from Elodea to light source,
same period of time in each light
condition before starting recording,
same water temperature, same sized
sample of Elodea).
The student collects and records
sufficient data relevant to the purpose
that enables a trend or pattern to be
determined, , e.g. number of oxygen
bubbles released over 5 minutes for
each wavelength; valid range, at least
4 wavelengths and repeats.
The student processes data relevant to
purpose that allows a trend or pattern
(or absence) to be interpreted e.g.
accurately as a table showing
averages or a calculation of bubbles
per minute or a graph of the results.
The student describes the presence
(or absence) of a trend as a fair
representation of the data and draws a
valid conclusion based on the
processed data
The student discusses biological ideas
relating to the investigation based on
the findings and those from the
resource materials or other source(s).
The student plans and describes a
method that includes a valid range
of the independent variable (e.g.
different coloured filters to provide a
range of at least four wavelengths,
with repeats, within 200nm of each
other), a valid measurement of the
dependent variable (e.g. number of
oxygen bubbles released, and
control or measurement of most
other variables / factors (e.g. same
light intensity, same distance from
Elodea to light source, same period
of time in each light condition before
starting recording, same water
temperature, same sized sample of
Elodea).
The student collects and records
sufficient data relevant to the
purpose that enables a trend or
pattern to be determined, , e.g.
number of oxygen bubbles released
over 5 minutes for each wavelength;
valid range, at least 4 wavelengths
and repeats.
The student processes data relevant
to purpose that allows a trend or
pattern (or absence) to be
interpreted e.g. accurately as a table
showing averages or a calculation of
bubbles per minute or a graph of the
results.
The student describes the presence
(or absence) of a trend as a fair
representation of the data and draws
a valid conclusion based on the
processed data
AND
(Note: The above ‘expected student
responses’ are indicative only and
relate to part of what is required.
Annotated, complete reports in
context that come from
previous/current students or
developed by teachers can be
included as examples of evidence.)
The student discusses biological
ideas relating to the investigation
based on the findings and those
from the resource materials or other
source(s).
The student justifies the choices
made during the in-depth
investigation by evaluating the
validity of the method or reliability of
the data.
The student explains the conclusion
in terms of the biology ideas relevant
to the investigation.
[Type text]
(Note: The above ‘expected student
responses’ are indicative only and
relate to part of what is required.
Annotated, complete reports in
context that come from
previous/current students or
developed by teachers can be
included as examples of evidence.)
A method that includes a description
of
 Independent variable - range of
conc. of sugar solutions. For
example, at least four
concentrations, either without
repeats, or all concentrations
above 0.3 mol L-1;
 Dependent variable – mass of
chips before & after; units of
measurement
 Control or measurement of some
(i.e. at least two) other variables /
factors e.g. same potato or
sample of potatoes, remove skin,
surface area of chips by similar
shape/size of chips, volume of
solution, cover to stop
evaporation, stated time chips in
solution, same conditions (eg
temperature), blotting dry before
weighing.
Collecting, recording and processing
of data relevant to the purpose
 Initial mass and final mass against
sugar conc.
 Data processed relevant to
purpose e.g. averaging of results
or calculation of % mass change
or graph
Reporting on the findings
 Conclusion reached based on the
processed data in relation to the
purpose of the investigation.
A method that includes a description
of
 Independent variable - valid range
of conc. of sugar solutions i.e. at
least four concentrations including
distilled water plus 0.3 mol L-1 or
below and above 0.3 mol L-1; with
repeats
 Dependent variable –
measurement of the mass of chips
before & after;
 Control or measurement of most
other variables / factors e.g. same
potato or sample of potatoes,
remove skin, surface area of chips
by similar shape/size of chips,
volume of solution, cover to stop
evaporation, stated time chips in
solution, same conditions (eg
temperature), blotting dry before
weighing.
 Evaluation of the investigation by
justification of the conclusion in
terms of the method used, such
as sufficient data, appropriate
range of IV, appropriate
processing using % mass
change, minimization or removal
of sources of errors, limitations,
bias.
Collecting, recording and processing of
data to enable a trend or pattern to
be determined
 Sufficient data recorded (valid
range, at least 4 concs and repeats)
 Data processing allows a trend or
pattern (or absence) to be
interpreted – accurate averaging of
results, calculation of % mass
change or appropriate graph.
Reporting on the findings
 Valid conclusion reached based on
the processed data in relation to the
purpose of the investigation.
 Discussion uses knowledge of the
process of osmosis to explain the
trend or pattern in the results
Final grades will be decided using professional judgement based on a holistic examination of
the evidence provided against the criteria in the Achievement Standard.
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Marking Schedule: Bio/2/1- Making Chips
Name _____________________________ Class_________
N
Requirements
A
M
Purpose of the investigation,as a hypothesis describing what will happen to
the chips in respect to osmosis
Method
Independent variable - range of conc. of sugar solutions. For example, at
least four concentrations, with either no repeats, or all concentrations
above 0.3 mol L-1;
 Dependent variable – mass of chips before & after; units
 Control or measurement of some (i.e. at least 2) other variables / factors
e.g. same potato or sample of potatoes, remove skin, surface area of
chips by similar shape/size of chips, volume of solution, cover to stop
evaporation, stated time chips in solution, same conditions (e.g.
temperature), blotting dry before weighing
 Independent variable - valid range of conc. of sugar solutions i.e. at
least four concentrations including distilled water, plus 0.3 mol L-1 or
below and above 0.3 mol L-1; with repeats
 Dependent variable – measurement of the mass of chips before & after;
 Control or measurement of most other variables/factors e.g. same
potato or sample of potatoes, remove skin, surface area of chips by
similar shape/size of chips, volume of solution, cover to stop
evaporation, stated time chips in solution, same conditions (e.g.
temperature), blotting dry before weighing.
Collecting, recording and processing
 relevant to the purpose
Initial mass and final mass against sugar conc.
Data processed relevant to purpose e.g. averaging of results or calculation
of % mass change or graph
 enable a trend or pattern to be determined
Sufficient data recorded (valid range, 5 concs and repeats)
Data processing allows a trend or pattern (or absence) to be interpreted –
accurate averaging of results, calculation of % mass change or appropriate
graph
Reporting




Conclusion reached based on the processed data in relation to the
purpose of the investigation
Valid conclusion reached based on the processed data in relation to the
purpose of the investigation
Discussion uses knowledge of the process of osmosis to explain the
trend or pattern in the results
Evaluation of the investigation by justification of the conclusion in terms
of the method used, such as sufficient data, appropriate range of IV,
appropriate processing using % mass change, minimization or removal
of sources of errors, limitations, bias
Overall Grade
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N
A
M
E
E
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Exemplar for excellence - Making Chips
Purpose:
When chips are placed in solutions with high concentrations of
sugar i.e. 0.7 mol L-1, the potato chips will lose mass as the chip
will lose water because of osmosis.
Purpose stating what
will happen to the chips
in respect to osmosis
Method:
1
Collect distilled water and sugar solutions; 0.1 mol L-1, 0.3
mol L-1, 0.5 mol L-1, 0.7 mol L-1.
2
Fill 3 test tubes with 10 mL 0.1 mol L-1 solution. Clearly
label each test tube.
3
Repeat with each of the other solutions
4
Cut 15 chips from the same potato to the same size and
shape using a cork borer.
5
Blot each chip with a paper towel.
6
Weigh each chip and place each one in each of the test
tubes. Record the weight of the chip and the test tube its in.
7
Cover each test tube with gladwrap.
8
Place all the test tubes in the same place in the fridge so
that the temperature remains the same.
9
Leave all chips in the solution for 12 hours.
10 Remove a chip, blot it dry with a paper towel, when
reweigh it. Record the final weight. Use the same
electronic scales to ensure consistency.
A method includes:
 valid range IV - five
conc including distilled
water plus 0.3 mol L-1
or below and above 0.3
mol L-1 (step 1);
 DV – mass of chips
before (step 6) & after
(step 10);
 Repeats (step 2 & 4)
 OV - volume of solution
(step 2), same potato
(step 4), same
shape/size chips (step
4), blotting dry before
weighing (steps 5 &
10), cover to stop
evaporation (step 7),
stated time (step 9),
same temperature
(step 8), same scales
(step 10).
Observations:
The chips in the water (0 mol L-1 sugar concentration) were slightly larger and felt firm,
turgid. The chips in the 0.7 mol L-1 were soft, flaccid. The chips in the 0.3 mol L-1 were
much the same as they started.
Sugar
Conc.
Mol L-1
O
mol L-1
0.1
mol L-1
0.3
mol L-1
0.5
mol L-1
0.7
mol L-1
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Original
mass (g)
Final mass
(g)
Difference in
mass (g)
% mass
change
3.0
3.0
3.3
3.0
3.2
2.9
3.0
2.9
3.2
3.2
3.0
3.1
3.1
3.3
3.0
4.0
4.1
4.2
3.5
3.6
3.3
3.0
3.0
3.2
2.8
2.6
2.7
2.2
2.4
2.0
1.0
1.1
1.1
0.5
0.4
0.4
0
0.1
0
-0.4
-0.4
-0.4
-0.9
-0.9
-1.0
33
37
33
17
13
14
0
3
0
-13
-13
-13
-29
-27
-33
Mean %
mass
change
34
15
1
-13
-30
[Type text]
Mean % change in mass of chips in different
sugar concentrations
Sufficient data
(valid range, 5
conc’s and repeats)
recorded and
processed to show
trend.
40
Mean % mass change
30
20
0.8
Trend shown by
accurate calculation
of % mass change
OR by the
appropriate graph.
Conclusion:
My results showed that the chips gained mass in water and low
sugar concentrations but lost mass in high concentrations of sugar.
This is what we predicted in higher sugar concentrations because
in these solutions the water will move out of the potato cells by
osmosis.
Valid conclusion
reached based on the
processed data in
relation to the purpose
of the investigation
10
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
-10
-20
-30
-40
Sugar concentration (mol L-1)
Discussion
When the chips were put in distilled water they gain mass because
the chips gain water from the surrounding solution due to osmosis.
The process of osmosis causes a net flow of water, across the
semi permeable membrane, along the decreasing water potential
gradient from a solution with a high water-potential to one with a
lower water potential. The chips gain water because the distilled
water has a higher water potential than the chips.
In solutions with a sugar concentration less that 0.3 mol L-1 the
water potential of the solution inside the cell is still lower than that
of the surrounding sugar solution so water moves into the potato
cells by osmosis. In the 0.3 mol L-1 solution the water potential of
the solutions inside and outside the cell are very similar so there is
very little net flow of water into the potato cells as can be seen by
the relatively small gain in mass of the potato chips.
As the concentration of the sugar solution increases from 0.3 to 0.7
mol L-1 the potato chip loses more and more mass because the
difference in water potential between the inside of the potato cells
[Type text]
Discussion uses
knowledge of the
process of osmosis
to explain the trend
or pattern in the
results:
 gained mass,
gained water,
due to osmosis
(water potential,
semi permeable
membrane, net
flow of water,
water potential
gradient)
 small mean %
change in mass,
small net water
flow
 loss of mass,
water loss, due
to osmosis
[Type text]
and the surrounding solution is increasingly different. This
means that when the chips are placed in the higher
concentration solutions more water will move out of the chips
as the result of osmosis.
EVALUATION:
My results showed that the chips gained mass in low sugar
concentrations but lost mass in high concentrations of sugar.
This conclusion is justified because I use a number of ways to
ensure I used the best method possible to make my
investigation a fair test. For example I used a cork borer to
make sure all the chips used were cut as close to exactly the
same shape as possible. This meant that each chip had the
same surface area available for diffusion of water across the
semi permeable membranes of the potato cells. The repeats
used showed similar results to each other.
A change made to my original method was to make the chips
slightly smaller than planned. This was because I had to get all
15 chips from the same potato so that I could control the
variable of water potential in cells in different potatoes.
The method was carried out in a way that variables that
could have changed the rate of osmosis, such as
evaporation and temperature, were controlled by covering
the test tubes with gladwrap and keeping them in the fridge
for 12 hours.
[Type text]
Evaluation of the
investigation by
justification of the
conclusion in terms of
the method used, such
as sufficient data,
appropriate range of IV,
appropriate processing
using % mass change,
minimization or removal
of sources of errors,
limitations, bias.