how science works

• • An accurate measurement is close to the true value. 
• • A precise measurement are ones where there is very little difference between the numbers. 
• • If you want precise measures of volume you would need to use the exact same piece of equipment for each practical completed
• • Reliability is when the results would be the same if you did the experiment again 
• • Repeatability is that when an experiment is completed using the same method and equipment that the results should be similar 
• A table must include – from left to right: 

  • A column for the independent variable (what you are CHANGING) 
  • A column for the dependent variable(s) (what you are RECORDING) subdivided into the number of repeats you will do
  • Usually (but not always) a column for any statistics e.g the mean and range of your data. 
• Calculating mean of results

  • A mean is an average of results
  • It is calculated by adding up all the numbers and dividing by the amount of results 
•  How do we know what to plot and where? 

  • The thing you measure goes on the y axis
  • The thing you change goes on the x axis
• Line of best fit

  • Once you have drawn a graph you may be asked to draw a line of best fit
  • A line of best fit is a line that best fits the data 
  • It DOES NOT have to be a straight line – it can be a curve but NEVER dot-to-dot
• • Sometimes, there may be results that do not fit the line. These are called anomalous results
•  Gradient

  • Gradient is the measure of how steep a line is. The bigger the gradient, the steeper the line.
• gradient = $\dfrac{y^2-y^1}{x^2-x^1}$
• Making Conclusions

  • When making a conclusion you need to mention both variables seen on the graph with data points mentioned