When you are doing your practical you will need to record your results in a table.
Rules for drawing and filling in Tables:
There must be a heading in the top row of the table. The heading must start with ‘Table to show. It must be a description of what’s in the table using your independent and dependent variable.
Draw the table in pencil using a ruler
The columns/rows must have headings with units. Units shouldn’t be in the columns
The independent variable must be in the first column or row.
The data must be in ascending order of the independent variable.
Analysing your results should allow you to find patterns or a story from your data.
Most likely you will see as the value of you indepentant variable increases, the data for your dependant date will also increase. this will show you that your independant variable is directly proprotional to your dependant variable.
If your dependant variable data is decreasing whilst your independant data is increasing, then your variables are indirectly proportional.
When you write your conclusion you will need to explain why this is happening.
When you plot a graph with your data, it makes it much easier to see if there is a pattern or a general trend in your data. It shows you if there is a relationship between the independent and dependent variable.
Most graphs you will draw in Science will either be a line graph or a bar graph.
Choosing the type of graph
The type of graph you draw depends of the type of data you have.
Types of Data
Continuous Data: the set of data is part of a numbered sequence and can have any value - this is when you draw a line graph.
Discrete Data: the set of data is part of a numbered sequence but is grouped into categories with no ‘in-between’ values e.g. calendar years. This is when you would draw a histogram.
Discontinuous Data: the set data does not form part of a numbered sequence but is in descriptive categories. It is not numerical, and does not have units. e.g. colours. This is when you draw a bar graph.
Choosing a Scale……
Drawing graphs can be a bit difficult but if you keep your scale simple then that should help a lot!
Important points to remember:
1. Your scale doesn’t have to be the same for the x and y axis, but your need to use a scale so you can fit all your points in.
2. If you work using a scale of going up in 1, 2, 5, or 10 it will make your graph easier to plot, and easier to read.
3. Your graph needs to be as big as possible so it’s more accurate and your scale must go up in equal intervals.
4. If you are going to be all fancy and draw a line of best fit then your axis must start at zero.
Writing a heading/legend for your graph
The heading/legend must be written below the graph. It must fully describe the graph. It must include:
the type of graph
the independent variable and the dependent variable
the context of the graph / conditions of the experiment
Line Graph to show the effect of changing light intensity on plant growth
Line Graph to show the effect of decreasing resistance on the speed of the current
Line Graph to show how increasing the temperature of water affects the time taken for 20grams of sugar to dissolve.
Bar Graph to show the number of different coloured cars driving through the school gates each day.
Can you see how you need to use both the independent and dependent variable to describe your graph in the heading?