Thank you purchasing this lesson titled Marshmallow Flight. More about this lesson can be found on my blog here: http://www.stemmom.org/2012/04/marshmallow puff tubes.html. This file contains two versions of the same lab. The first is a commonly used version in which students follow directions, collect data, and answer post lab questions. This cookbook version s purpose is to demonstrate the concept of unbalanced forces. The second version of this lab is a higher level inquiry lab, where students move through the scientific method with ideas they have about how to make a marshmallow fly further. For more information on which lab might be best for your students, go to the link mentioned above. I would greatly appreciate your comments on my blog and/or on my Teachers Pay Teachers Account. Also please be sure to read my terms of use below before using this product. Again, Thank you so much! Sincerely, Darci the STEM Mom http://www.stemmom.org All downloads are copyright protected. Please feel free to use these downloads for your own personal family and classroom use. You are welcome to: Save the files to your computer and print off copies for yourself or classroom whenever you would like If you comment on the lesson publically; online or in presentations please mention and link directly to my website (http://www.stemmom.org) Write blog posts (or post photos on a school website) that include photos of your students using my files as long as proper credit is given to Darci the STEM Mom, with a link back to post where the STEMmom.org lesson is described. Post the electronic version of the lesson online ONLY if: o It is for student/parent access AND o It is password protected (not accessible by the general public) You may not: Post the electronic version of the lesson online with the intent to share it with other teachers, educators, and administrators. Host any of my files as your own Sell any of my files
Name Science Course Pre Lab Due Post Lab Due Grade Your Challenge Marshmallow Flight A Demonstration of Unbalanced Forces Experiment with cardboard tubes of different lengths and marshmallow placement within the tube, to see how far you can propel a marshmallow using only your breath. Materials 2 Toilet paper tubes Paper Towel Tube or 1 file folder Scissors Masking tape or transparent tape Full Size Marshmallows Flour Measuring tape Cardboard Tube Assembly You need to make or obtain a short cardboard tube (length of a toilet paper tube) and a longer tube (length of a paper towel tube). To make the longer tube, cut a rectangle from the file folder about 29.5 cm (the entire width of an unfolded file folder) by about 19 cm (11.5 in. by 7.5 in.). Place one of the long edges of the file folder inside the other, and tighten to form a tube (see Figure 1) that fits around the circular shape of a marshmallow snug enough so that there's no air space around the marshmallow, but not so tight that the marshmallow won't be able to move. It may be easier to make the tube if you first pull the folder over the edge of a table to establish an initial curvature. When the tube is rolled to the appropriate size, tape it so it maintains this size. Then place tape along the entire length of the seam on the tube to seal it. Take extra care to be sure that the tube is the same diameter the entire length of the tube.
3 Let s Get the Marshmallow Airborne 1. Roll the marshmallow in flour, then shake it or tap it to remove any excess. The flour will help prevent any sticky spots on the marshmallow from sticking to the tube. 2. Place the marshmallow in the end of the short toilet paper tube. Holding the tube horizontally put your mouth over the empty end, and blow hard into the tube (see Figure 2). Measure how far the marshmallow travels and record both the measurement and a few notes about its flight and landing in the data table. You need to whether you will measure from where it first hits the ground, or its placement after it stops moving, then record all measurements in the same way. You may also want to run several trials and then pick a measure of central tendency like the average. 3. Again place the marshmallow in the end of the tube, but this time put your mouth around the end of the tube where the marshmallow is located. Keeping the tube horizontal, blow hard against the marshmallow itself, so that it has to travel the length of the tube before exiting (see Figure 3). Be sure to keep the tube horizontal, and keep blowing the whole time the marshmallow is in the tube. Did the marshmallow go farther this time? Trouble shooting: If you blow and the marshmallow won't move, check the diameter of the tube. The tube may either be too tight (in which case friction prevents it from moving) or too loose (in which case air blows right by the marshmallow instead of pushing it). 4. Repeat steps 2 and 3 using your longer length tube. Marshmallow Flight Data Table Distance(s) Description of the flight Short cardboard tube w/ marshmallow at the far end Short cardboard tube w/ marshmallow at the near end Long cardboard tube w/ marshmallow at the far end Long cardboard tube w/ marshmallow at the near end
4 The Physics Behind Marshmallow Flight While the marshmallow is in the tube, your blowing increases the air pressure in the tube, creating a force on the marshmallow. As long as this force is greater than the friction force, there's an unbalanced force on the marshmallow. According to Newton's second law, F = ma, an unbalanced force accelerates an object. The speed of the marshmallow will keep increasing for as long as the marshmallow experiences an unbalanced force. As soon as the marshmallow leaves the tube, your blowing no longer affects it. But the faster the marshmallow is traveling when it leaves the end of the tube, the farther it will travel before hitting the ground. In the first case, with the marshmallow initially placed at the far end of the tube, the marshmallow falls out the end of the tube almost as soon as you blow on it. So the unbalanced force on it doesn't last very long, and the marshmallow doesn't get going very fast or travel very far. In the second case, when you blow the marshmallow the length of the tube, it experiences an unbalanced force for the entire length of the tube. Since the force acts for a longer time, the marshmallow is going faster when it leaves the tube, and it therefore travels farther. The length of tube that will provide maximum speed is really determined by how long you can keep blowing strongly enough to maintain enough pressure in the tube so that the force produced on the marshmallow is larger than the friction force. If you have really big lungs, you can use a very long tube, and get the marshmallow moving really fast! Extra Fun: Want a challenge and something to do on a Friday night with friends? Try using a significantly longer tube double or triple the length of the file folder tube. Try elevating the tube at different angles above the horizontal to see the effect on range. What's the absolute maximum range you can achieve for the marshmallow? What combination of tube length and elevation gives this range? Do the results vary from person to person?
5 Post Lab In the Expected Results column of the Marshmallow Flight Analysis Table, place a number 1 next the tube that based on the physics, should have propelled the marshmallow the furthest. Continue rating in order so you have 1 4, with 4 representing the tube that should have had the shortest distance. Referring to your Data Table, use the same rating 1 4 in the Actual Results column, only rating what actually happened. In the Explanation column, if the expected results match the actual results, explain the physics of why that tube performed the way it did. If the actual results did not match the expected results, in the Explanation column, describe factors that may have influenced the results. Marshmallow Flight Analysis Table Short cardboard tube w/ marshmallow at the far end Expected Results Actual Results Explanation Short cardboard tube w/ marshmallow at the near end Long cardboard tube w/ marshmallow at the far end Long cardboard tube w/ marshmallow at the near end 1. Using the tubes you already constructed, how could you cheat to make your marshmallow go further?
6 2. Keeping in mind your answer to number 1, write a list of rules for a competition between several people to make it fair. Come up with at least three. a.. b.. c.. d.. 3. Generally speaking, does your data support the physics of unbalanced forces? How could you fix your tubes or how you perform your trials, to match the expected results? 4. Predict: What would happen if you doubled or tripled the length of the tube? Why? 5. Considering all of the factors that make a marshmallow fly, if you could make ONE tube, describe its construction, and how you would run the trials. Draw a sketch too, if that helps. References The directions of this lab, including the figures, were copied from the Exploratorium Snacks Website. However, data table, and all post lab questions are original to STEMmom.org. http://www.exploratorium.edu/snacks/marshmallow_puff/index.html (Accessed November 2012) Marshmallow Puff Tubes from STEMmom.org http://www.stemmom.org/2012/04/marshmallow puff tubes.html Baird, Dean. "The Blowgun as a Teaching Tool." The Physics Teacher (February 1996): 98 100. van den Berg, Ed, Jover Nunez, Alfredo Guirit, Cotton Buds. "Momentum and Impulse." The Physics Teacher (January 2000): 52 53.
Name Science Course Pre Lab Due Post Lab Due Grade Your Challenge Marshmallow Flight An Inquiry into Flight Factors Experiment with cardboard tubes to see how far you can propel a marshmallow using only your breath. 7 Possible Materials Toilet paper tubes Paper towel tube or cardstock Scissors Masking tape or transparent tape Full size marshmallows Flour Measuring tape Brainstorming 1. What factors do you think may propel a marshmallow further through a tube using only your breath? Brainstorm a list of marshmallow flight factors below. Playtime Using your gathered materials, play with the items to test factors that help the marshmallow to go the furthest. Your goal during this playtime is to pick ONE factor to test systematically. Therefore, as you play, think about how you will develop a scientifically fair way to test this one factor. After your playtime, you will develop a procedure to test how this one factor. Here are some specific questions to help guide your thinking. How can I test variations of this one factor, fairly? How can I be sure that each trial is the same every time?
How can I be sure other factors of propelling a marshmallow aren t being tested while I m testing my factor? How can I accurately measure and compare how far the marshmallow travels? 8 Planning (you must have this part approved before beginning testing) 2. The marshmallow flight factor that I m choosing to study is: 3. In the Experimental Design Table below, describe the varying levels you are testing. The control is the group to which you compare the other groups. Remember, each level should be varying degrees of the SAME factor. Experimental Design Table Control Group Level 1 Level 2 Level 3 4. Prediction: Which group or level do you think will propel marshmallows the furthest? 5. List the constants, or conditions you ll need to keep the same every time you test. (You should have a long list here!) 6. In your science lab notebook, or on another piece of paper, design a data table where you will collect measurements and take notes for experiment. Remember to run several trials for each group, then find a central tendency (mean, mode, or range). Your instructor must approve 1 6 before you move onto the next page. Instructor s signature
9 Procedure Conduct your experiment testing your marshmallow flight factor. Record results in your data table, then after you ve finished, write a detailed procedure list that others could use to replicate your experiment. Write this procedure in your science lab notebook, or a separate sheet of paper. Experiment Analysis 8. I predicted that the group would propel marshmallows the furthest. My data showed that the group propelled marshmallows the furthest. 9. What is the physics behind your experiment? You may need to do research to help you answer this question. 10. Explain why your prediction was supported by your data, or why it was not (use research from your answer to number 9). 11. What unforeseen issues came up in the marshmallow flight testing session?
10 Post Lab Questions 1. How might another person say that your procedure did not accurately measure the factor you were testing? (Addressing procedural weaknesses/inconsistencies, ways people could repeat your experiment but get different results.) 2. For each factor mentioned in the previous question, describe changes to your procedure that would make it better. 3. Using the observations of the marshmallow flight factors that your classmates tested, describe the features of a marshmallow tube design that would shoot a marshmallow the furthest and also explain why! References Marshmallow Puff Tubes from STEMmom.org http://www.stemmom.org/2012/04/marshmallow puff tubes.html