# Graphs in Physics

1. Sep 13, 2015

### Jimmy87

1. The problem statement, all variables and given/known data
Hi, this isn't really a homework assignment but just a question that will help with some of my homeworks I do get given. I am struggling with understanding about where to start graphs on the x-axis. If I plot a graph where I have the values 90,100,110,120,130 and 140 on the x axis then if I start at zero on the x-axis my graph ends up on one side.

2. Relevant equations
None

3. The attempt at a solution
There are two ways I know of to go about correcting this but have no idea which one to use and why there are two!

First method - start the x axis at 90 (i.e. where it would normally be x=0) since this is my first data point.

Second method - start the x-axis at x=0 then draw a little squiggly line thing (no idea what they are called) and then start at 90 after the squiggly line.

From looking around online a lot of people seem to do the squiggly line thing but I have no idea why because why would you ever do method 2 when you could do method one? Method two seems pointless and a waste of space on the graph when you can just start your graph at 90 or am I missing something? Which one should I use?

2. Sep 13, 2015

### Bystander

You use whatever method your teacher/instructor/editor demands you use. In the long run, you'll be relying on analytical methods (curve fitting, least squares, etc.) to describe your data.

3. Sep 13, 2015

### SteamKing

Staff Emeritus
You don't mention what the y-values are for the x-range of 90-140.

In any event, it is not always necessary (and often it is counterproductive) to start all x-y plots at (0,0). You want to choose the range of x values and y values which best present the data, which is the reason for making a graph in the first place.

4. Sep 13, 2015

### Jimmy87

Thanks for the answers people. The first y value is close to zero so I could start the y-axis at y = 0. But I don't know why people would put x=0 in with a squiggly line and then start at 90 rather than just starting the x axis at 90?

5. Sep 13, 2015

### SteamKing

Staff Emeritus
Without seeing a graph drawn with a break in the x-axis, it's hard to say, unless there is information of interest on both sides of the break which is shown.