teaching experimental design year 7 integrated curriculum
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What actually is an “experiment”? A science experiment tests a hypothesisTRANSCRIPT
Teaching experimental designYear 7 Integrated Curriculum
What is an “experiment”?• In school, “experiment” is often used
to describe hands-on experiences
What actually is an “experiment”?• A science experiment tests a
hypothesis
Components of an experiment• Background research• Aim• Hypothesis• Equipment• Types of variables• Results• Discussion• Conclusion
Background research• Every experiment starts with a topic
of interest (Eg. What are the effects of ocean acidification on living things?)
• Background research finds out what we already know about the topic
Aim• Always starts with “To”• Tells the reader what the
experiment aims to do• Eg. To find out how
ocean acidification affects the shells of living things
Hypothesis• A prediction of the results based on
the background research• Example – The more acidic the
ocean is, the quicker the shells of ocean invertebrates will dissolve
If A happens then B will happen
Equipment and Method• List the equipment used in
the experiment• Method lists how to do the
experiment in steps• Always starts with a verb• Accompanied by a
scientific diagram where appropriate
Types of variables• Independent variable – What we change on purpose (Eg.
how acidic the water is)
• Dependent variable – What we measure as the result (Eg. How much shells have dissolved after 3 days)
• Controlled variables – What we keep the same to keep the experiment fair (Eg. The amount of acids and water; the type of shell; the temperature of the environment)
• In most experiments there is ONE independent variable, ONE dependent variable and many controlled variables
Types of variables - Strategies• Cows Moo Softly
– Change one thing– Measure one thing– Keep everything else the same
Controlled variables vs control
3M HCl with shell
2M HCl with shell
1M HCl with shell
Water with shell
•Independent variable - concentration of acid•Dependent variable – how much each shell dissolves•Controlled variables – time of experiment, amount of acid and water, type of shell•Control – the water with shell
Validity and reliability• Validity – Is the experiment testing
what you intend to test?
• Reliability – Are these results a fluke? If I repeated the experiment again, will I get the same results?
Replication• You shouldn’t just have
one beaker of 3M acid, one beaker of 2M acid, etc.
• You need 5 beakers of each acid so that there is replication.
• Replication increases reliability.
• You’ll need to use average calculations.
Results• A table and graph must be
done• A graph shows patterns
that cannot be seen easily in a table
• It’s usually a choice between a column graph or a line graph
• X-axis = independent variable
• Y-axis = dependent variable
Discussion – analysis of results• What do the results mean?• Are the results expected? Are
there any usual results?• What were some possible
sources error?• How can the experiment be
improved?• What are some other
experiments to do in the future?
Conclusion• The aim written in past tense and
says whether the hypothesis is correct
• Eg. The effects of ocean acidification on shells were determined. The more acidic the water, the faster shells dissolve. The hypothesis was correct.