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SBA
guidelines (cont'd)
Monacia
Williams, Contributor
Last
week, we looked at a sample mark scheme
for an experiment used to test the
skills for ORR (observation, reporting,
recording). I hope you learned something
that will help you in writing up your
own experiments. This week, we will
look at a written example that would
give you 10 marks based on that mark
scheme.
Remember,
all written experiments require certain
common headings. These are: Date,
Topic, Aim, Apparatus/Materials, Method,
Results, Discussion and Conclusion.
For ORR, having all of these headings
written in the correct order will
get you a mark. Let us see how closely
your written experiments come to this
one. Remember also that all experiments
must be written in reported speech
or the past tense. You are giving
a report of work that you have done,
not work that you are going to do
or are still doing!
Date:
This is the day on which the experiment
was done.
Topic:
Enzymes
Aim:
To investigate the effect of pH on
enzyme activity.
Apparatus/Materials:
Pill bottles, paper circles, beaker,
forceps, petri dish, stopwatch, potato
extract, hydrogen peroxide, buffer
solutions of pH 3, 4, 5, 6, 7 and
8.
Method:
1.
50 cm2 of each buffer solution was
placed into pill bottles labelled
pH 3, 4, 5 6, 7 and 8.
2.
10 cm3 of hydrogen peroxide were added
to each pill bottle.
3.
20 circles of paper, made using a
paper punch, were collected in a dry
pill bottle.
4.
10 cm2 of potato extract were collected
in another pill bottle.
5.
A single circle of paper was dipped
into the extract and left for 10 seconds.
6.
The forceps were used to remove the
paper circle and to place it into
the pill bottle labelled pH 3.
7.
As the paper was placed into the solution
the stopwatch was started. As soon
as the paper rose to the top of the
solution the watch was stopped.
8.
The time was recorded in a table;
this was done twice more.
9.
Steps 5 to 8 were repeated for each
solution. The average time taken for
the paper to rise in each solution
was calculated.
10.
The information recorded in the table
was used to plot a graph of rate of
reaction against pH.
Results:
Table showing the effect of changing
pH on the action of the enzyme catalase
Graph
showing the effect of changing pH
on the action of the enzyme catalase
Another
thing that you must always note is
that you should not draw a graph without
first creating a table. The table
holds the information that you need
for the graph!
Guess
what? This is all we have time for
this week. Next week, we will continue
with the discussion and conclusion
for this experiment. Until then, have
a wonderful week!
Monacia
Williams teaches at Glenmuir High
School. Send questions and comments
to kerry-ann.hepburn@gleanerjm.com
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