Ex. Acid corrosion
Outcomes:
present data as a graph
draw conclusions from a graph
evaluate evidence
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Carl set up an experiment to show the effects of acid corrosion. Some fizzy drink was placed in a flask and some pieces of limestone were added. The whole apparatus was placed on a balance and the mass was taken every minute. The results are shown in the table.
Activity:
Write the title "Acid Corrosion" in your exercise book.
Make a copy of the table in your exercise book and fill in the gaps by calculating the missing results.
Plot a graph of overall mass lost against time. (Need help, click here)
When was the mass being lost fastest? __________________________________________________
Use your graph to estimate how much mass had been lost after 30 seconds. ____________________
Either use dictionary or search for "define: corrosion" on the internet. Write the definition in your exercise book.
How can you tell that no more corrosion took place after 12 minutes? __________________________
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Carl said that this experiment proved that the acid in the fizzy drink had corroded the limestone.
Emma said that she didn’t think that this was a fair test, as fizzy drinks go flat if you leave them to stand and you might have got these results anyway without adding the limestone.
Apart from the change in mass, what could you see that would support Carl’s conclusion?
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Do you agree with Emma’s evaluation? How could you improve the experiment and get extra evidence to check on Emma’s idea?
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