Graphing Project Name Kyle O'connor ______________________________ (_____/45 Points) Date ___10/12 _______ Period _7_____ Introduction Graphs can be powerful tools. If done well, a graph of your data allows you or another reader to easily see patterns, trends, or other important aspects of your data. This is particularly true when there are lots of data. While there are many types of graphs, most scientific graphs are made by plotting points and then showing the trend of the data with a line or field. Lines can be straight or curved, but usually merely summarize data. In other words, the line does NOT connect the data points, nor do all data necessarily fall near the line. The line simply shows a trend and is called a best-fit line (or trend line). A best-fit line will have an equal \"weight\" of data above it and below it and can be either linear (i.e. a straight line) or curvilinear (i.e. exponential or polynomial). Trend lines on a graph allow the reader to interpolate and extrapolate data. Interpolation - predicting a data point that is between existing data points. Extrapolation - predicting data points that are outside of the existing data range. Most science graphs are XY scatter plots. The independent variable (I.V.) - something the experimental 'controls' is plotted on the X axis. The dependent variable (D.V.) - things that are measured and change as a result of the I.V. are plotted on the Y axis. Directions: 1. Graph the data for the 2 assigned practice problems on a piece of graph paper. 2. Answer the questions that go with the graphs. 3. Turn your graphs into the bin, make sure your name is on your graphs. 4. Submit your project in google classroom. Practice Problem 1 The volume of a gas decreases as the temperature of the gas decreases. A sample of gas was collected at 100 degrees Celsius and then cooled. The changes in the volume of the sample are shown below. Temperature (0C) 100 80 60 40 30 20 10 0 Volume (mL) 317 297 288 278 252 243 236 233 Questions and analysis 1. (4 points)Extrapolate the graph to reach a gas volume of 320mL. Describe what this means. 2. (4 points) Describe the relationship between the Temperature and the Volume (Is it linear or nonlinear? Is it direct or indirect?)? The graph is linear because the graph is straight, and could keep going on forever as the volume could keep increasing and the tempeture could keep rising. Practice Problem 2 Like most matter, when liquids are heated they expand. The concept is called thermal expansion. In this experiment, a scientist slowly warms 3 different liquids. The liquids are in syringes with no air space. Periodically, the scientist measures the volume of the liquids and the temperature of the liquid. They get the following data. Temperature ( C) 30.0 35.0 39.0 44.0 51.0 54.5 57.0 62.0 68.5 0 Questions and analysis Water 0.0 0.8 1.6 2.7 4.2 5.1 5.8 6.9 9.1 Rise of liquid in the tube (cm) Burner Fuel 0.0 3.1 5.2 7.8 12.1 15.3 1. (3 points) Which liquid or liquids expand at a constant rate? 2. (3 points) Which liquid or liquids do not expand at a constant rate? 3. (1 point) Which liquid expands at the fastest rate? Glycerin 0.0 1.3 2.4 3.8 5.7 6.7 7.4 8.7 10.4 Rubric for Graphs Description Points Title 2 X axis labeled 1 Correct units for X axis 1 Properly scaled X axis 1 Y axis labeled 1 Correct units for Y axis 1 Properly scaled Y axis 1 I.V. and D.V. on correct axis 1 Points plotted correctly 3 Neatness 3 Total 15 Graph 1 Graph 2