1. Working Scientifically
1. Asking scientific questions
Scientists make observations and have ideas which can lead to scientific questions. A scientist will then conduct an investigation and collect data to try and answer their questions.
Some scientific questions may start with …
What affects …
How does … affect ….
You would then conduct an investigation to try to find out the answer.
Variables: There are 3 types of variables in an investigation.
Independent variable: The variable that you change.
Dependent variable: The variable that you measure / observe.
Control variables: The variables that stay the same (constant) so they do not affect the results.
Scientists can make a prediction: a statement stating what they think will happen.
2. Planning investigations
First you have to plan an investigation. You need to think about what you will do and what data you will collect to be able to find out the answer to your question.
A plan includes :
The scientific question you are trying to answer
The equipment you will use
The method you will follow, including the independent, dependent and control variables.
How to ensure the data is accurate and precise
How to reduce the uncertainty
How many measurements you will take and the range.
How you will stay safe
A prediction of what you think will happen
Data:
Data should be repeatable and reproducible.
Data can be continuous, discrete or categoric. .
3. Recording data
Data is usually recorded in a results table.
Scientists take repeat readings to increase the reliability of data.
You can then check for outliers (anomalous results) which are results that either do not fit the pattern, or are very different from the other repeats.
To deal with an outlier you might circle the result and then exclude this when calculating a mean (average).
To calculate a mean you add up the results in one row and then divide by the number of results.
You can then present your data in a graph.
Which graph do I use?
If the independent and dependent variable are continuous, then use a line graph.
If the independent variable is categoric then use a bar chart.
Sometimes discrete or categoric data can be displayed in a pie chart.
For both graphs plot the independent variable on the X axis and the dependent variable on the Y axis.
Graphs should have a title, labels for each axis, drawn with pencil and ruler and drawn to fit the page.

2. Working Scientifically
4. Analysing data
Your graph will show how the independent variable affects the dependent variable.
To find a pattern in your graph you may need too draw a line of best fit (a line or curve that goes through as many points as possible. Outliers are ignored.
Your graph will show what happens to the dependent variable as the independent variable is changed / increased.
You can then write a conclusion. This includes saying what happened in the investigation and your scientific explanation as to why this happened.
Finally you would compare your results with your prediction – where you correct?
Errors and uncertainty:
The 2 types of error in scientific measurements are random error and systematic error.
Suggesting improvements:
Could you have:
Taken more readings
Used a larger range
Use more accurate equipment
5. Evaluating data
You should:
Discuss the quality (how good) of the data you have collected.
Suggest and explain improvements to the method to increase the quality of the data
Poor quality data may have:
Lots of outliers
A large spread of data (large difference between highest and lowest in repeats). .