 In this video, I'm going to show you how to work with the Hubble data set if you happen to be using the LibreOffice free spreadsheet program. Now again, you guys are going to have to download the data and you're going to be working with Subset 1. I'm going to step through the whole process here with the Subset 2 file so that you can see exactly how to work with this in LibreOffice. Normally if you open a program by right clicking on it, you can open it in the default program or you can specify what program you want to open it with. Since this computer has both Excel and LibreOffice, I want to choose LibreOffice. If your computer has Excel, you might as well use Excel. LibreOffice is more the option for if you didn't happen to have Excel. So when this opens up, it's going to recognize that this is not already a spreadsheet file and it's going to want to make sure that things are being read in properly. You should be able to see things that look like numbers down here. Otherwise you might need to change some of the settings up here in order to figure out and get that working right. If you have any questions, let me know. Once it's opened as a spreadsheet, you'll notice we have one column for the Galaxy IDs, one column for the distances in units of Megaparsecs, and one column for the velocities as kilometers per second. We want to select both columns B and C, but rather than trying to select it down here in the data, go ahead and select it in the top bar and that will select the entire column. Now at this point, we want to go ahead and insert a chart. Now we could come up here to insert and chart, or there's a shortcut over here on the side. In LibreOffice, the first thing you need to do is choose which type of chart, and we want an XY Scatter type chart. You can set a few different things in here, but we're going to go ahead and click on Finish to give us our chart. Now this chart does not have everything on it that we'd like to, so we're going to insert some different chart elements here. So we come over here to the Insert menu. Now you still have to have the chart in gray. If for some reason you had clicked off of it, you have to actually select the chart by double clicking on it until there's a gray border around it, and then you can start to add extra chart elements. And the first thing we want to do is go ahead and add some titles. Now in this case, we can just type in our titles. So for example, the main title might be Hubble's Law. The X-axis, if you remember, was the Distances, so we would go ahead and type in Distance and select Megaparsecs. And then for the Y-axis, we would type in that that represents the velocity, and it was in kilometers per second. And then we can click on OK, and notice it's now added those titles to our graph. I'm going to come over here and we're going to go ahead and add in some extra grids. Now it has Y grids there, but I actually want all four, the Major XY and the Minor XY. When you do that, it's going to just add some extra lines in here to make it a little easier to estimate things off the graph. And we can make things bigger as well to be able to estimate more clearly. The last thing that we're going to want to do is to add a trend line. Now if I come over here to insert, you'll notice that the trend line isn't visible because it needs to know for sure which data it's adding the trend line to. So in order to fix that, you have to come back into your plot window and click on the data. And it's very subtle, but it's showing us now all the little data points. When you've done that and you come over to insert, now the trend line option is available. So there's several things we're going to want to do with this trend line. For the type, we want it to be linear, but we want to also force the intercept to be zero. And we want to show the equation. Now in LibreOffice, you can actually say that my X variable is really the distance, so I'll call that D. And my Y variable is really the velocity, so I'll call that V. And then it's going to give me the equation. Now on your lab report, it has this equation set up with V equals and then there's a spot to enter a number D. You don't need to put all of these decimal points out there. You can just enter it in, round it off to two decimal places. This isn't the exact number that you're going to be using because remember this is the fit for the subset two. But you should have some other number that's similar to 65.81. It should be in a similar range for that number. And that's the number that you'll be entering in your lab report. Now I can come over here and click on this line. And I can actually format that line and give myself a little bit more clarity here. I'm going to make it a nice bright color and I want to make it a little bit of a thicker line. You don't have to do that. It just makes it easier for you when you actually go through to figure out and answer your questions based on this data. Now the last and probably one of the most important steps is you're going to have to turn this file in with your lab report. So we need to come up here and save. Now they generally have a save button here or you can use the file menu to save. But when you save it's going to bring up a warning that there's things in here that don't fit the text CVS format. You want to go ahead and use the ODF format. That's going to save it as a LibreOffice spreadsheet. And you can keep it as the same name or just for clarity. You can go ahead and add your last name in there and save that file. And you will submit then this file, which is a spreadsheet file to me. If you had wanted to, you could actually save this not as an ODS file, but as a Excel file. And then somebody who only has Excel would be able to open this one as well. I have both programs so it doesn't matter to me whether you save it as an Excel file or a LibreOffice file. But make sure what you save has your graph that has your trend line, your equations, and your titles in there. Then use this graph to be able to answer the questions in your lab manual. If you have any difficulty creating this, get in touch with me right away so that I can help you out.