Drawing graphs

1 / 7

# Drawing graphs - PowerPoint PPT Presentation

Drawing graphs. Give the graph a title . (What you are investigating.) Draw the axes and put the independent variable on the horizontal axis. The dependent variable goes on the vertical axis. Dependant variable plotted on the vertical (y) axis.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'Drawing graphs' - clemens

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Drawing graphs

Give the graph a title. (What you are investigating.)
• Draw the axes and put the independent variable on the horizontal axis.
• The dependent variable goes on the vertical axis.

Dependant variable plotted on the vertical (y) axis

Independent variable plotted on the horizontal (x) axis

The independent variable is the one that you control and choose values for.
• The dependent variable is the one that changes as a result of your choice.

Example

• The Length of a pendulum goes on the horizontal axis and the time it takes to swing goes on the vertical axis.

(Time usually goes on the horizontal axis but in this case the time it takes to swing depends on the length of pendulum you choose.)

Select your scales so that the points extend over most of the graph paper but leave room to label the axes.

The origin of the graph is the point where the two axes meet.

This usually has the value of zero.

Number the scales evenly.

Labelthe axes with the correct units.

For example.

'Current in mA'. You may also use 'Current/mA'. This

means that the current , say 5mA, divided by the unit mA

gives the number 5 which is marked on the axis.

6

5

Voltage V

4

3

2

origin

1

Current mA

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85

Use a sharp pencil to mark your points as finely as possible, but make sure that they are clearly visible. A small circle around each point makes it easier to see where they are. You may also use a small cross to mark your points.
• Join up the points.
• For an obvious trend (pattern) you should draw a straight line or a smooth curve . You may find it easier to draw a curve if you have your hand inside the curve.
• If you decide to draw a straight or curved line you may find that some of the points are not on the line. You will have to draw a line of best fit. Ignoring any obviously wrong points, try to draw a line which leaves about the same number of points above the line as below the line.
If you draw a triangle to measure the gradient (slope) of a straight line, make the triangle big so that your measurements are accurate. Make sure that you draw your triangle to the line and not to points you have plotted which are not on the line.

6

5

Voltage V

4

Change in y-axis

3

2

1

Change in x-axis

Current mA

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85

To calculate the gradient (slope) of the line use the following formula:

change in x

change in y