{"id":784,"date":"2019-08-28T23:41:47","date_gmt":"2019-08-29T03:41:47","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/?post_type=chapter&#038;p=784"},"modified":"2019-08-28T23:42:22","modified_gmt":"2019-08-29T03:42:22","slug":"5-4-lab-activity-testing-a-terminal-speed-hypothesis-using-coffee-filters","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/chapter\/5-4-lab-activity-testing-a-terminal-speed-hypothesis-using-coffee-filters\/","title":{"raw":"5.4 Lab Activity :  Testing a terminal speed hypothesis using coffee filters","rendered":"5.4 Lab Activity :  Testing a terminal speed hypothesis using coffee filters"},"content":{"raw":"<h2 class=\"entry-title\">LAB: TESTING A TERMINAL SPEED HYPOTHESIS<\/h2>\r\n<div id=\"post-392\" class=\"standard post-392 chapter type-chapter status-publish hentry chapter-type-standard contributor-mickdavis\">\r\n<div class=\"entry-content\">\r\n<h2>TERMINAL SPEED<\/h2>\r\n<h3>Materials:<\/h3>\r\n<ul>\r\n \t<li>lab sheet and writing utensil<\/li>\r\n \t<li>calculator<\/li>\r\n \t<li>10 Coffee filters<\/li>\r\n \t<li>step ladder allowing you (or a partner) to reach 2\u00a0\u00a0<strong>m<\/strong><\/li>\r\n \t<li>ruler with<span>\u00a0<\/span><strong>cm<\/strong><span>\u00a0<\/span>units<\/li>\r\n \t<li>scale with at least 0.1 gram<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3807\">precision<\/button><\/li>\r\n \t<li>spreadsheet and graphing software<\/li>\r\n \t<li>for distance learners, access to online forums, videos, and help features for the spreadsheet software will likely be necessary<\/li>\r\n \t<li>one of the following equipment sets:\r\n<ul>\r\n \t<li>\u00a0motion sensor + computer with control and analysis software<\/li>\r\n \t<li>video motion analysis app (<a href=\"https:\/\/www.vernier.com\/products\/software\/video-physics\/\">example<\/a>)<\/li>\r\n \t<li>camera (slow motion mode preferred) + stopwatch with 0.01<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<h3>Observation<\/h3>\r\nWe observe that when a body falls through the air it eventually reaches a maximum<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4035\">speed<\/button>, known as<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button>, which is roughly 200<span>\u00a0<\/span><strong>mph<\/strong>.\r\n<h3>Question<\/h3>\r\nThis phenomena\u00a0 raises the question: What determines the value of the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button>?\r\n<h3>Search Existing Knowledge<\/h3>\r\nFind an answer for what determines the value of the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button>. Write the answer below and also list your source.\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n<h3>Hypothesis<\/h3>\r\nOur search of existing knowledge told us that one factor affecting<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button><span>\u00a0<\/span>was the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button><span>\u00a0<\/span>of the object.\r\n\r\nProvide a<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3753\">qualitative<\/button><span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3732\">hypothesis<\/button><span>\u00a0<\/span>on how the terminal speed depends on the mass of an object. That means state if you think the terminal speed will increase or decrease when mass increases. Explain your reasoning.\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n<h3>Test<\/h3>\r\nTo test your hypotheses, without jumping out of airplanes, we measure the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button><span>\u00a0<\/span>of coffee filters with varying<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button>. The terminal speed for coffee filters is much slower than for bodies and they will typically reach terminal speed in less than 2 meters of drop distance. These properties will make our experiment doable\u00a0 in the lab. Your hypothesis was about an object\u2019s terminal speed and mass in general, not about bodies specifically, so a coffee filter experiment will still test your hypothesis.\r\n\r\nMeasure the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button><span>\u00a0<\/span>of the coffee filter and record here:___________\r\n\r\nOur method will be to drop\u00a0 coffee filters from a height of at least 2\u00a0<strong>m\u00a0<\/strong><span>\u00a0<\/span>and measure the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button>. You will\u00a0 need a step ladder and a partner to make the measurements. You can measure the terminal speed using photogates an an acoustic or laser motion sensor if you have access to those in your lab. If not, you can measure the terminal speed by using a video motion analysis app, or by simply filming the last 0.1<span>\u00a0<\/span><strong>m<span>\u00a0<\/span><\/strong>(10<strong><span>\u00a0<\/span>cm)\u00a0<\/strong>of the fall with a ruler and a running stopwatch are visible in the video frame.\r\n\r\nIf using the motion sensor, be sure to only use the section of the speed data after the speed has become<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4064\">constant<\/button><span>\u00a0<\/span>and before impact. Your instructor will help you find this section of data. Record your terminal speed here:______________\r\n\r\nIf using the filming method, be sure to film straight on to the ruler, which should be standing up straight on the floor. Read off the time off the stopwatch in the video when the filter passes the 10<span>\u00a0<\/span><strong>cm<\/strong><span>\u00a0<\/span>mark and again when it hits the floor. Subtract the first time from the second to find the difference between these times. Divide 0.10\u00a0<strong>m\u00a0<\/strong>by the time difference to get the terminal speed.\u00a0 Record your terminal speed here:______________\r\n\r\nRepeat this experiment for two nested (one inside another) coffee filters. Nesting the coffee filters increases the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button>, but doesn\u2019t change the shape of the filters, allowing us to change only one<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4239\">variable<\/button><span>\u00a0<\/span>at at time. Record your<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button><span>\u00a0<\/span>for two filters in the chart. Also measure the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button>of the two filters and record in the chart as well.\r\n\r\nRepeat the experiment until you have measured terminal speed and mass for at least 5 nested coffee filters. Record the number of filters and<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button><span>\u00a0<\/span>for each in the table below:\r\n<table>\r\n<tbody>\r\n<tr>\r\n<td>Number of Filters<\/td>\r\n<td>Terminal speed (m\/s)<\/td>\r\n<td>Mass (g)<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>1<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>2<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>3<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>4<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>5<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>6<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>7<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>8<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>9<\/td>\r\n<td><\/td>\r\n<td><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<h3>Analyze<\/h3>\r\nEnter your data into a spreadsheet and create an x-y graph of terminal speed vs. mass.\u00a0 Mass should be on the horizontal (x-axis) because mass is the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4240\">independent variable<\/button><span>\u00a0<\/span>(what you are purposefully changing). Speed should be on the vertical axis (y-axis), because speed is the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4241\">dependent variable<\/button><span>\u00a0<\/span>(what is changing in response to the independent variable).\r\n\r\nBe sure to give your graph a title and label the axes with the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4239\">variable<\/button><span>\u00a0<\/span>names and the units of measure.\r\n<h3>Conclusion<\/h3>\r\nWas your<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3753\">qualitative<\/button><span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3732\">hypothesis<\/button><span>\u00a0<\/span>supported by the data? Explain.\r\n\r\n&nbsp;\r\n\r\nBe sure to save your spreadsheet and graph. We may use them again during this course.\r\n\r\n&nbsp;\r\n<h3>\u00a0Hypothesis Testing Including Uncertainty*<\/h3>\r\nIn order to really answer the question about whether or not the experimental results support the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3732\">hypothesis<\/button><span>\u00a0<\/span>we need to to think about<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3768\">uncertainty<\/button>.\r\n\r\nLet\u2019s do a little experiment to determine how<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3809\">random error<\/button><span>\u00a0<\/span>affects the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3807\">precision<\/button><span>\u00a0<\/span>of your results. Repeat the final filter set measurement 6 more times and record the results, including the first value you found above, in a chart:\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\nUse your spreadsheet software (or some other method) to take the average and the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4243\">standard deviation<\/button><span>\u00a0<\/span>of the seven values. Record both below:\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\nThe<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4243\">standard deviation<\/button><span>\u00a0<\/span>value will serve as an estimate of the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3807\">precision<\/button><span>\u00a0<\/span>in our experiment. A new measurement should be within the standard deviation of the average value 68% of the time.\u00a0We will use the precision provided by the standard deviation as our estimate of the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3768\">uncertainty<\/button><span>\u00a0<\/span>in our\u00a0 final\u00a0 measurement.\u00a0Ideally we would base our average and standard deviation on more than seven values, we will use only seven in this learning situation, simply for the sake of time.\r\n\r\n&nbsp;\r\n\r\nAdd error bars to the terminal speed data in your graph, setting the size equal to the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4243\">standard deviation<\/button><span>\u00a0<\/span>you calculated.\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\nConsidering the error bars, does the data support your<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3753\">qualitative<\/button><span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3732\">hypothesis<\/button>? Explain your reasoning.\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\nSo far we have ignored systematic error.<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3810\">Systematic errors<\/button><span>\u00a0<\/span>can be difficult to recognize and even more difficult to quantify. We must always be on the look out for sources of systematic error. Can you provide a possible source of systematic error in your experiment? Explain.\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n<\/div>\r\n<\/div>","rendered":"<h2 class=\"entry-title\">LAB: TESTING A TERMINAL SPEED HYPOTHESIS<\/h2>\n<div id=\"post-392\" class=\"standard post-392 chapter type-chapter status-publish hentry chapter-type-standard contributor-mickdavis\">\n<div class=\"entry-content\">\n<h2>TERMINAL SPEED<\/h2>\n<h3>Materials:<\/h3>\n<ul>\n<li>lab sheet and writing utensil<\/li>\n<li>calculator<\/li>\n<li>10 Coffee filters<\/li>\n<li>step ladder allowing you (or a partner) to reach 2\u00a0\u00a0<strong>m<\/strong><\/li>\n<li>ruler with<span>\u00a0<\/span><strong>cm<\/strong><span>\u00a0<\/span>units<\/li>\n<li>scale with at least 0.1 gram<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3807\">precision<\/button><\/li>\n<li>spreadsheet and graphing software<\/li>\n<li>for distance learners, access to online forums, videos, and help features for the spreadsheet software will likely be necessary<\/li>\n<li>one of the following equipment sets:\n<ul>\n<li>\u00a0motion sensor + computer with control and analysis software<\/li>\n<li>video motion analysis app (<a href=\"https:\/\/www.vernier.com\/products\/software\/video-physics\/\">example<\/a>)<\/li>\n<li>camera (slow motion mode preferred) + stopwatch with 0.01<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>Observation<\/h3>\n<p>We observe that when a body falls through the air it eventually reaches a maximum<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4035\">speed<\/button>, known as<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button>, which is roughly 200<span>\u00a0<\/span><strong>mph<\/strong>.<\/p>\n<h3>Question<\/h3>\n<p>This phenomena\u00a0 raises the question: What determines the value of the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button>?<\/p>\n<h3>Search Existing Knowledge<\/h3>\n<p>Find an answer for what determines the value of the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button>. Write the answer below and also list your source.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<h3>Hypothesis<\/h3>\n<p>Our search of existing knowledge told us that one factor affecting<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button><span>\u00a0<\/span>was the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button><span>\u00a0<\/span>of the object.<\/p>\n<p>Provide a<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3753\">qualitative<\/button><span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3732\">hypothesis<\/button><span>\u00a0<\/span>on how the terminal speed depends on the mass of an object. That means state if you think the terminal speed will increase or decrease when mass increases. Explain your reasoning.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<h3>Test<\/h3>\n<p>To test your hypotheses, without jumping out of airplanes, we measure the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button><span>\u00a0<\/span>of coffee filters with varying<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button>. The terminal speed for coffee filters is much slower than for bodies and they will typically reach terminal speed in less than 2 meters of drop distance. These properties will make our experiment doable\u00a0 in the lab. Your hypothesis was about an object\u2019s terminal speed and mass in general, not about bodies specifically, so a coffee filter experiment will still test your hypothesis.<\/p>\n<p>Measure the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button><span>\u00a0<\/span>of the coffee filter and record here:___________<\/p>\n<p>Our method will be to drop\u00a0 coffee filters from a height of at least 2\u00a0<strong>m\u00a0<\/strong><span>\u00a0<\/span>and measure the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button>. You will\u00a0 need a step ladder and a partner to make the measurements. You can measure the terminal speed using photogates an an acoustic or laser motion sensor if you have access to those in your lab. If not, you can measure the terminal speed by using a video motion analysis app, or by simply filming the last 0.1<span>\u00a0<\/span><strong>m<span>\u00a0<\/span><\/strong>(10<strong><span>\u00a0<\/span>cm)\u00a0<\/strong>of the fall with a ruler and a running stopwatch are visible in the video frame.<\/p>\n<p>If using the motion sensor, be sure to only use the section of the speed data after the speed has become<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4064\">constant<\/button><span>\u00a0<\/span>and before impact. Your instructor will help you find this section of data. Record your terminal speed here:______________<\/p>\n<p>If using the filming method, be sure to film straight on to the ruler, which should be standing up straight on the floor. Read off the time off the stopwatch in the video when the filter passes the 10<span>\u00a0<\/span><strong>cm<\/strong><span>\u00a0<\/span>mark and again when it hits the floor. Subtract the first time from the second to find the difference between these times. Divide 0.10\u00a0<strong>m\u00a0<\/strong>by the time difference to get the terminal speed.\u00a0 Record your terminal speed here:______________<\/p>\n<p>Repeat this experiment for two nested (one inside another) coffee filters. Nesting the coffee filters increases the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button>, but doesn\u2019t change the shape of the filters, allowing us to change only one<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4239\">variable<\/button><span>\u00a0<\/span>at at time. Record your<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button><span>\u00a0<\/span>for two filters in the chart. Also measure the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3830\">mass<\/button>of the two filters and record in the chart as well.<\/p>\n<p>Repeat the experiment until you have measured terminal speed and mass for at least 5 nested coffee filters. Record the number of filters and<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4026\">terminal speed<\/button><span>\u00a0<\/span>for each in the table below:<\/p>\n<table>\n<tbody>\n<tr>\n<td>Number of Filters<\/td>\n<td>Terminal speed (m\/s)<\/td>\n<td>Mass (g)<\/td>\n<\/tr>\n<tr>\n<td>1<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>2<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>3<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>4<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>5<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>6<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>7<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>8<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td>9<\/td>\n<td><\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Analyze<\/h3>\n<p>Enter your data into a spreadsheet and create an x-y graph of terminal speed vs. mass.\u00a0 Mass should be on the horizontal (x-axis) because mass is the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4240\">independent variable<\/button><span>\u00a0<\/span>(what you are purposefully changing). Speed should be on the vertical axis (y-axis), because speed is the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4241\">dependent variable<\/button><span>\u00a0<\/span>(what is changing in response to the independent variable).<\/p>\n<p>Be sure to give your graph a title and label the axes with the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4239\">variable<\/button><span>\u00a0<\/span>names and the units of measure.<\/p>\n<h3>Conclusion<\/h3>\n<p>Was your<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3753\">qualitative<\/button><span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3732\">hypothesis<\/button><span>\u00a0<\/span>supported by the data? Explain.<\/p>\n<p>&nbsp;<\/p>\n<p>Be sure to save your spreadsheet and graph. We may use them again during this course.<\/p>\n<p>&nbsp;<\/p>\n<h3>\u00a0Hypothesis Testing Including Uncertainty*<\/h3>\n<p>In order to really answer the question about whether or not the experimental results support the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3732\">hypothesis<\/button><span>\u00a0<\/span>we need to to think about<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3768\">uncertainty<\/button>.<\/p>\n<p>Let\u2019s do a little experiment to determine how<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3809\">random error<\/button><span>\u00a0<\/span>affects the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3807\">precision<\/button><span>\u00a0<\/span>of your results. Repeat the final filter set measurement 6 more times and record the results, including the first value you found above, in a chart:<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Use your spreadsheet software (or some other method) to take the average and the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4243\">standard deviation<\/button><span>\u00a0<\/span>of the seven values. Record both below:<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>The<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4243\">standard deviation<\/button><span>\u00a0<\/span>value will serve as an estimate of the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3807\">precision<\/button><span>\u00a0<\/span>in our experiment. A new measurement should be within the standard deviation of the average value 68% of the time.\u00a0We will use the precision provided by the standard deviation as our estimate of the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3768\">uncertainty<\/button><span>\u00a0<\/span>in our\u00a0 final\u00a0 measurement.\u00a0Ideally we would base our average and standard deviation on more than seven values, we will use only seven in this learning situation, simply for the sake of time.<\/p>\n<p>&nbsp;<\/p>\n<p>Add error bars to the terminal speed data in your graph, setting the size equal to the<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-4243\">standard deviation<\/button><span>\u00a0<\/span>you calculated.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Considering the error bars, does the data support your<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3753\">qualitative<\/button><span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3732\">hypothesis<\/button>? Explain your reasoning.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>So far we have ignored systematic error.<span>\u00a0<\/span><button class=\"glossary-term\" aria-describedby=\"392-3810\">Systematic errors<\/button><span>\u00a0<\/span>can be difficult to recognize and even more difficult to quantify. We must always be on the look out for sources of systematic error. Can you provide a possible source of systematic error in your experiment? Explain.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<\/div>\n<\/div>\n","protected":false},"author":9,"menu_order":5,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-784","chapter","type-chapter","status-publish","hentry"],"part":327,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/pressbooks\/v2\/chapters\/784","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/wp\/v2\/users\/9"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/pressbooks\/v2\/chapters\/784\/revisions"}],"predecessor-version":[{"id":785,"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/pressbooks\/v2\/chapters\/784\/revisions\/785"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/pressbooks\/v2\/parts\/327"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/pressbooks\/v2\/chapters\/784\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/wp\/v2\/media?parent=784"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/pressbooks\/v2\/chapter-type?post=784"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/wp\/v2\/contributor?post=784"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/physicsforlifesciences1phys1108\/wp-json\/wp\/v2\/license?post=784"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}