Back To CourseEarth Science: Middle School
12 chapters | 101 lessons
As a member, you'll also get unlimited access to over 75,000 lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed.Try it risk-free
Paul has been teaching middle school science for the last 10 years, and has his bachelors degree in Elementary Education.
You can make wallets with it, fix cars, and even make old cardboard boxes new again. Astronauts fixed the lunar dune buggy with it, and NASA sends some on every space mission they run, especially after fixing an air filter on the Apollo 13 mission. It's been used as a quick fix on oil wells and was used to keep World War II ammunition boxes dry. Some EMT handbooks describe ways to close up a chest wound with it. This item can be used to remove warts and could keep your windows from shattering in a storm. It's been said that if you can't fix it with this, you just aren't using enough. I'm, of course, talking about that silvery shape shifter - duct tape.
Duct tape has so many uses; don't you wish that everything was like that? I'm going to let you in on a little secret. There is something you might be using right now that has just as many uses. You use them at school, your parents use them at work, you find them online, and even that little picture telling you how much battery life you have left is one of these - they're graphs! Just like duct tape, graphs have thousands of uses! They can sway peoples' minds, be used to display parts of something bigger, and even show how something like temperature changes over the day. Can your fancy schmancy duct tape do that? I didn't think so.
So, what are graphs, and why do we use them? A graph is just a different way to look at data. Some people like reading charts, some like reading about numbers in a paragraph, others like looking at a picture representation, and that's where graphs come in. Graphs are a picture representation of numbers or data. It's as simple as that, but there are four main things about graphs that you need to remember before you can successfully make one.
First, don't start before you collect all your data. Second, graphs need to show data as a picture. Third, there's many types of graphs - each suited for a specific need. Using the proper graph to display data is crucial. Last, graphs need to have labels and titles that inform the reader. To help remember these four ideas, think of this mnemonic device: Don't Pick This Lemon. It's an acronym that you can help associate with the four ideas.
Look, the 'D' in 'Don't' is just like don't start without your data. The 'P' in 'Pick' is for pictures - we're making pictures out of data. The 'T' in 'This' stands for this graph type or that type - there's always a specific one to use. Finally, the 'L' in 'Lemons' is so you don't leave a sour face on anyone trying to figure out what your information is about on your graph. Remember, Don't Pick This Lemon! Let's look at these four ideas in more detail with some examples.
As you already know, there's quite a variety of different graphs out there. You see them everywhere, but what's a person to do? There's so many graph types! There's pie graphs, box and whisker plots, bar graphs, stem and leaf plots, and line graphs. Not to mention Venn diagrams, word clouds, donut charts, info graphics, histograms, area charts... this list could go on for quite awhile.
Clear that jumbled pile out and let's focus on just a couple examples: pie graphs and line graphs. Remember, we're just looking for a new way to represent data as a picture. For example, you've probably seen something like this before; it's called a pie or a circle graph:
Just like duct tape has many specific uses, graphs have many specific uses, too.
A pie graph is useful in situations where there are parts of a whole or a percent of something. A good use of this type of graph would be a representation of what gases make up Earth's atmosphere, like we have here. These are all parts of a greater whole. Look at oxygen, it's red here. Since it makes up 21% of our atmosphere, it takes up 21% of this graph. Nitrogen is 78% of our atmosphere. See how that has a larger portion on the graph? There's also a tiny sliver of other gases in yellow which makes up the last 1%. If you were to add up all these numbers up, they would total 100%. A pie graph always needs add up to 100%.
Next, you need to have some written information on your graph explaining what's being shown. These are called labels, and every graph needs to have some type of label. Pie graphs need to have a way to identify what's being shown by each color. Usually, this is shown by something called a key or a legend, which is a small box in the corner explaining what each color represents. It should be simple and clear because too much info can make the graph hard to read.
Finally, all graphs need to have a title. The title needs to explain what's being represented by the graph. A good title, for this example, would be something like Earth's Atmospheric Gases or Gases Found in Earth's Atmosphere. These should be big and easy to read and placed somewhere out of the way of the chart's data.
Let's review our four main parts: Don't Pick This Lemon! After we collected data, we looked at a pie graph, which represented numbers by displaying different colors. This type of graph shows parts of a whole. Last, we looked at the title - the graph above is a great example of a pie graph.
Circle graphs are great for many things, but could you graph something like how the temperature changed at the beach on Tuesday with this type of graph? Actually, no. To make a graph with this type of data, a circle graph just won't work. But, not to fear! There are many graph types - we just need to pick the one that will represent these numbers better.
On one particular space walk, astronauts needed to get at a piece of material that was sticking out on the bottom of the space shuttle. If they couldn't get it with their gloved hands, they had a set of pliers. If that didn't work, they had made this new tool out of a hacksaw blade and, you guessed it, some duct tape. The point is, they knew they needed a better option if one way wasn't going to work. Now, we're in the same position. A pie graph just won't work for temperature.
A more appropriate graph to use in this situation would be a line graph. This type of graph is best used to show a trend or change over time. If the temperature starts out low and then gets warmer as the day progresses, a line graph would be a perfect way to show that data trend. Let's make this graph together. Here's what your data might look like:
Unlike the pie graph, this set of numbers does not have a whole part - temperature doesn't work that way. This graph will show data as points on a line. But, before we can do any plotting, we need to set this graph up. It's actually a bit like going to the beach. If you set your blankets and chairs out before you set up your umbrella, you might be outside the shaded area. We don't want that.
Graphing is similar because you need to set up the chart before you can place points. There are two important things we need to do before graphing. First, line graphs have two pieces of data called variables. Our two variables are temperature and time. One of these needs to go up and down on the side of the graph, the other goes along the bottom of the graph. These are called the dependent and independent variables. The independent variable always goes on the bottom of your graph, and the dependent variable goes on the side of the graph. Sound messy? Let's simplify things a bit. Look at the word - the dependent variable is something that depends on the other item.
In our situation, the temperature will change based on what time of day it is. The sun comes out and makes the beach hot. That makes temperature our dependent variable, so it goes on the left side of our graph. Normally, dependent variables are things like numbers or money values. Time (our other variable) will keep passing no matter what temperature it is. Time doesn't depend on anything here. Typically, independent variables will be things like items, places, or time. As our independent variable, time goes on the bottom of the graph.
Next, we need to pick numbers or values for the graph that make sense for what we're graphing. If you look at our data, we don't have any numbers above 88 degrees. We also have no numbers below 72 degrees. We won't need any numbers that go into snowy territory here, nor do we need numbers that will boil water. They just don't make sense for our graph. Let's pick a round number just a bit lower than 72, maybe 70. Now, let's pick something just a little higher than 88, how about 90? We'll use these two as our starting and stopping points on the graph.
Keep your number range just to the data that you have. Since we have plenty of space, let's have each space count as one number on our graph, but you could count by any number here. Go ahead and place all the numbers in between onto your graph. I'm going to count by twos here to save space, but each line is still counting just one degree. Use the space you have to make the best sized graph possible - not too big, not too small.
We also need to look at the independent variable - time. Let's space each hour out on the bottom so that the graph is not too cluttered. So, now that we have our variables set, let's put some data points on it! At 10:00 o'clock in the morning, the temperature was 72 degrees. Look at your graph; you need to find both the 10 a.m. time and the 70 degree mark.
See the place where they intersect? That's where you need to put your first dot. Now, place the rest of those dots on the graph the same way. Once you finish plotting all your points, it should look like this:
After that, you need to connect the dots to show how the temperature changes. After all, this is called the line graph!
There you have it - your graph is almost complete. Can you think of something that we're missing? Take a few seconds to think. You remember the title, right? How about Beach Temperatures on Tuesday? Perfect!
Did we cover all our important parts? Check our mnemonic device: Don't Pick This Lemon! Did we have our data first? Yes. Did we represent the numbers with a picture and did our graph suit the needs of our data? Yes and yes. Are there labels and a title? Yep, no sour taste here - this a great example of a line graph:
See, graphs are not as scary as some people think. Graphs are simply a way that we represent data with a picture. There were two types of graphs that we looked at today: pie graphs, or circle graphs, which show parts of a whole; and line graphs, which are useful for showing a change or trend in data.
You also need to remember the four main things that graphs have: Don't Pick This Lemon! First, every graph needs data, and it needs to be collected before you start graphing. Next, graphs make a picture to represent numbers or data. Third, like duct tape, graphs have many functions, and there's a specific function for every need (this graph over that one). Finally, every graph needs a set of labels and a title so everyone who sees it can make sense of the information presented and has no sour lemony faces.
Following this video lesson, you will be able to:
To unlock this lesson you must be a Study.com Member.
Create your account
Already a member? Log InBack
Did you know… We have over 160 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.
To learn more, visit our Earning Credit Page
Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.
Back To CourseEarth Science: Middle School
12 chapters | 101 lessons