ISA - Section 2 Flashcards
Draw a sketch graph of case study 1
Label the axis
Draw the shape of the graph
Explain whether or not the results in case studies 1, 2 and 3 support the hypothesis
Statement, trend and quote data for each
If it doesn’t support, mention anomalous results, validity, and if they calculated mean correctly
Case study 4 question
Do if it supports, trend and quote data for each part of the results
How could the results from your investigation be useful in the context you have researched?
Used by home-owners wanting to know how hard their local tap water is
The high temperatures of the water in central heating systems of homes cause the calcium ions in the hard water to react with carbonate ions and form solid limescale (calcium carbonate) inside the pipes. The home-owners would want to know if this could affect them
If they used my experiment and found out that their water was hard they would fit an ion exchanger into their water system which would soften all of their tap water
Suggest an uncertainty in your investigation. How would you reduce the size of this uncertainty if you were to repeat the experiment?
When filling the pipette to 10cm^3, the person filling the pipette might be looking at the pipette from above or below and misjudge if the sulphate solution has reached 10cm^3
The way to reduce this uncertainty is for the person measuring the amount of sulphate solution in the pipette to ensure their eyes are level to the 10cm^3 marking on the pipette when measuring the 10cm^3 of sulphate solution
Explain how you would use repeated readings to get more accurate results
Calculate the mean
By adding together repeated readings and dividing by the number of repeated readings
Find and discard anomalous results before calculating a mean
Did you get any anomalous results?
Statement that was anomalous results
Statement that anomalous results are ones that don’t fit the pattern
Quote repeated readings to show that result is anomalous
Other people trying to repeat your investigation might get different results to yours. Suggest one reason and explain why they would get different results
They may have used different values for their control variables
An example of this is if they added a different amount of sulphate solution into their conical flask
If they used a larger amount of sulphate solution, the amount of soap solution added to form a long-lasting lather would increase
Was your resolution appropriate?
The resolution of the burette measuring the amount of soap solution added was 1cm^3
This was a suitable resolution because the resolution which the volume of soap solution added was measured at was small enough so that you could see a clear difference between the results of group 1 and group 2. However, the resolution wasn’t small enough to see clear differences between the metal ions within the groups
Quote one result from group 1 and one from group 2
Do your results support the hypothesis that you investigated?
The results did support the hypothesis
Because in the graph, when group 2 rather than group 1 metal ions were used to make the water hard, the amount of soap solution added to form a long-lasting lather increased
Quote sodium sulphate (group 1) and magnesium sulphate (group 2)
Explain why a variable might be continuous or categoric
The measurement of a continuous variable might take any value and will be a number with units
A categoric value will have discrete values and will not use numbers or any type of sequence
You have been given results obtained by other people. Do these show that this investigation is reproducible?
The results obtained by other people show that the investigation is reproducible
In my results, when the type of metal ion is changed from sodium to magnesium, the amount of soap solution added to form a long-lasting lather goes from 1 to 11 cm^3
In the other group’s results, the amount of soap solution added to form a long-lasting lather goes from 1 to 10 cm^3 meaning the experiment is reproducible
