Chemistry 1.14 INTERNAL CREDITS

MS GIBELLINI

Achievement StandardCarry out an in-depth practical chemistry investigation involves:

developing a procedure for collecting primary data, with units, relevant to the purpose, based on the manipulation of the independent variable over a valid range of values with repetition to show reliability

controlling the variable(s) that could have a significant effect on the results

using techniques to increase the accuracy of the measured values of the dependent (and independent) variable

processing and representing the data to enable a conclusion to be reached

writing a conclusion based on the processed data that links to the purpose of the investigation.

Carry out a comprehensive practical chemistry investigation involves an in-depth investigation that also:

justifies the choices made to increase accuracy during the investigation

justifies the conclusion in terms of the processed data and the purpose of the investigation

relates investigation findings to applicable chemistry ideas.

Topic Plan

Basics – graphs, tables, report writing

Fair testing

Practice assessment 1 – Calcium Carbonate – step by step

Practice assessment 2 – Rhubarb – mark at the end +

feedback

Summative Assessment – submit for final grade, resubmits for

minor errors and those on grade boundaries only

Aim/Purpose – what you are trying to find out

Equipment – gear you are going to need

Hypothesis – the results you expect

Method – steps and diagram

- independent variables – thing you change

- dependent variables - result you record

- controlled variables – keep same to make fair test

Results – data and graph, averages, percentages, calculations

Conclusion – answers aim and refers to hypothesis

Discussion – links your results with scientific ideas

Evaluation – what went well, what and how you could have improved the experiment, how

reliable the results are

Experimental Format

Independent variable (that which you purposefully change) is in the left column,

Dependent variable (that which you measure) with the different trials is in the next

columns,

Average at the end (add up values and divide by how many values there are)

Title: Clearly state the purpose of the experiment, headings need to have units

Tables

Average

http://www.kscience.co.uk/animations/graph4.htm

Graphs must have:

Title

Labelled axis

Units

Ruled lines

Even spacing

Graphs

In order for an experiments results to be valid the experiment must

have been carried out fairly:

- Accurate - Measurements taken accurately

- Reliable - Experiment repeated

- Valid - Conditions controlled so that only one thing changes

- Reliable - Sufficient information is collected

- Repeatable - Sufficient details (including a diagram) are

recorded

Fair Tests

Independent Variable = thing you change,

include the range and units

Dependent Variable = results you record, include

the expected range and units

Controlled variables = things you keep the same

to make it a fair test, must say how you will keep

them the same

Variables;

If we wanted to test to see if Drive or Surf is a better washing powder what

would our:

Independent Variable be (thing we change)?

Brand of washing powder

Dependent Variable be (thing we record):

Measure stain size/weight or colour (using a colour chart)

Controlled Variables be (things we need to keep the same):

Amount of water in wash, amount of powder, size of stain, type of

clothing, washing cycle, water temperature, type of stain

Washing Powder

Remember:

Students can discuss and plan their experiment in small groups, but everything

written in their assessment booklet must be done individually, test conditions

You must make up their own dilution series from a stock bottle. A good

suggestion is to record in their booklet as a table rather than having to explain

step by step.

as a time saver, make up the total amount of each acid dilution needed all at once, rather than doing it trial by trial

really important that the conclusion relates/refers in some way to the aim written

at the beginning

Show some sort of processing of data - averaging/graph etc.

Talk about the collision theory for the higher grades

Must refer to rate/frequency/collisions per second. It's not enough to say there

were more collisions. Must link it to time/rate in some way.

Things to Remember:

Units, units units

Valid range (at least 4)

Repetition (at least 3)

Controlling the variable(s) – say what and how for at least 3.

Accurate method – details, amounts, units, times etc

Processing and representing the data – averages graphed, follow graphing rules

Conclusion links to the purpose of the investigation

Conclusion is justified using data from results

justifies the choices made to increase accuracy during the investigation

justifies the conclusion in terms of the processed data and the purpose of the investigation

Relates investigation findings to applicable chemistry ideas.

Justifies results validity of method