Investigative Experiment

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Investigative Experiment
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Recall ...

• Sec 1 - students taught and tested on C1 and C2
  skills.
• C1 - using and organising techniques, apparatus
  and materials
• (to measure mass and volume of a piece of
  cork)
• C2 - observing, measuring and recording
• (investigating acidity alkalinity of
  solutions using different indicators)

3
Recall ..

• Sec 2 - taught and tested C3
• C3 - handling experimental observations and data
• (effect of temperature on the activity of
  salivary amylase)

4
C4 - mini investigations

• Most demanding of the 4 practical skills
• it involves planning, carrying out and evaluating
  investigations

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Hypothesis ...

• Eg 1- to test the hypothesis that an increase in
  temperature will increase the amount of solute
  that can dissolve in a solvent.
• Eg 2 - to test the hypothesis that dropping a
  magnet can affect the number of of paper clips
  attracted to it.

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1st step plan the investigation

• What to observe and measure
• What apparatus is needed
• Which variables to keep constant
• and which to change
• How many observations to make

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• Definition
• Solubility max amount of solute which can
  dissolve in a given amount of solvent at a fixed
  temperature.
• Temperature degree of hotness or coldness of an
  object

variables
constants
Apparatus Beaker, spatula, measuring cylinder,
stirrer, thermometer, stopwatch, Materials Common
salt, hot water
To investigate how solubility depends on
temperature
What to observe and measure ?
How many observations to make ?
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Variables

• Independent variable the one that is purposely
  changed
• Dependent variable the one that is measured

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Controlled variables (constants)

• The ones that are kept constant

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Identifying variables and use of variables
Example 1 Title The effect of dropping of
magnet on its strength Problem statement The
aim of this study is to find out if dropping of
magnet affect the number of paper clips attracted
to it.
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Independent variable
Number of times magnet was dropped
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Dependent variable
Number of paper clips attracted to magnet
Constants
Height from which magnet was dropped, size of
paper clips, magnet
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Quick check ..
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• Definition
• Solubility max amount of solute which can
  dissolve in a given amount of solvent at a fixed
  temperature.
• Temperature degree of hotness or coldness of an
  object

Variables Independent variable temperature of
solvent (water) Dependent variable the no. of
spoonfuls of solute
Constants type of solvent type of solute amount
of solvent
Apparatus Beaker, spatula, measuring cylinder,
stirrer, thermometer, stopwatch, Materials Common
salt, hot water
To investigate how solubility depends on
temperature
What to observe and measure ? The temp of the
water has to be measured. To amt of solute (salt)
that can dissolve in each temp of water has to be
observed.
How many observations to make ? cold water
tap water hot water 1
1 1 as long as all the solutes have
dissolved in a given temp.
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Carry out investigations

• Deal with any inconsistent results by retesting
  in a systematic way.
• Suggest modifications to original plan and carry
  them out if you have the time

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Write a report

• Use the following format
• aim
• apparatus materials
• procedure
• observation and results (tabulate results)
• conclusion

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Example of a table
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Instructions

• Individual work
• Form a hypothesis, plan, carry out, write report
• After briefing, at least 1 week of hands on and
  hand-holding

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Deadlines .

• Submission of plan (end of term 2)
• Carry out investigations (during holidays)
• Reminder take pictures of your experiment as
  evidence
• Submission of report ,5th week of Term 3
• (week of 28th July 2003)

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Have fun planning and investigating
This powerpoint slides is available at
http//www.angelfire.com/alt/mdm_faridah or
Peicai Sec website.