Practising Graphs

Why do we use graphs? To help us see trends To see the relationship between 2 variables (e.g. how temperature of water cools over time) To be able to predict the values of certain things

Read “Displaying your results” on page 6 of the books Which graph type do I choose? If both the variables have numbers draw a line graph (e.g. temperature cooling over time) If one variable is a number and the other is a word or category draw a bar graph (e.g. mass of different types of trees) If one is a percentage and the other is a word or category draw a pie chart (e.g. percentage of time taken up doing variety of activities over the day)

Drawing a pie chart Use a protractor and a compass To calculate the number of degrees for each percentage: your percentage X 360 100 …so 20% would be represented by 72 degrees on your protractor 20 X 360

Which variable goes where? The input variable always goes on the x axis and the outcome variable always goes on the y axis

How do I draw the line on a line graph? Do not join up the dots First look for a trend If the trend shows a straight line, then use a ruler If there is a curve, draw a neat curve

You must not forget to: Label the axes Include units in the labels (e.g. cm, mins, g) Write a title

Look at the “Interpreting Graphs” part of your sheets Cover with a piece of paper, all the information written next to the graphs In pairs, discuss what each graph shows. Write down 2 sentences for each and then check your answers.

Now you will practice drawing some graphs Draw a graph of the results on page 4 on the effect of the amount of protein in food on the weight of mice. Write a 1 line description. P. 259, Q3 – work out the missing value (don’t draw the table) and draw a pie chart of the values P. 113, Q3 – sketch the graph and answer a and b (not c).

Plenary Design a quiz on graphs and ask your partner. You have 3 minutes to design a quiz of 5 questions – including diagrams.