Rocket Activity Using Dependent and Independent Variables This rocket activity is intended to be used with early middle school students. It can be used to illustrate a number of related principles in science education including inquiry, independent and dependent variables, problem solving, engineering principles, and critical thinking. Not to mention being fun! You will construct simple rockets made from paper and powered by air using the instructions below. You will launch your rockets and record either the height attained, distance traveled, or time. Then you will change your design slightly and launch again recording new data. Integrated into this process is a discussion of independent variables (IV), dependent variables (DV), and control variables (CV). An independent variable is a variable that you change or manipulate while a dependent variable is a variable that you measure as the result of the independent variable. The control variable is a variable that you often cannot control such as temperature or pressure or location. Because of this you want to have the same control variables whenever you conduct your experiments. Goals and Objectives 1. Students will demonstrate Newton s third law of motion for every action, there is an equal and opposite reaction as the basic principle of rocket propulsion.. Students will understand that when an independent variable is manipulated, it will affect the results of the responding dependent variable.. Students will become familiar with the parts of a rocket, as they construct LSC (Launch System Compressor) models, and its general design. 4. Students will model positive attitudes, persistence, inventiveness, curiosity, and critical thinking as they complete the rocket launch activity. Constructing the Rocket and Launch System Compressor (LSC) Materials One gallon zipper-lock plastic bag 8 ½ x 11 sheets of paper at least 4 pieces transparent tape duct tape scissors cotton ball stop watch (or digital watch) meter sticks graph paper (cm) 1
Procedure (see attached illustrations) 1. Roll one sheet of paper lengthwise to create a long tube approximately 15 mm in diameter. Tape the seam with transparent tape to prevent the tube from unrolling.. Use the scissors to cut off one bottom corner of your freezer bag to create a hole that your tube will fit into snugly.. Insert one end of the tube into the bag and out through the hole in the bottom. Slide the tube through the hole until just a few millimeters remain inside. Tape the tube in place with duct tape. 4. Form a cone using a second sheet of paper that is approximately cm long and 4 to 5 cm in diameter at its widest point. Secure seam with transparent tape. 5. Determine where the body of the cone is.5 cm in diameter and cut away the base of the cone at that point. This should leave you with a cone at that point. This should leave you with a cone that is approximately 0 cm long. 6. To reduce eye injury during launches, use duct tape to attach a cotton ball to the tip of the cone to cover the point. Also, wrap duct tape around the cotton ball before taping to rocket to help with the correct weight proportions. 7. Cut out three identical fins from a third piece of paper and attach them to the base of the cone using transparent tape. 8. If necessary, inflate the bag with air by blowing into the tube. 9. Place the bag on a sturdy, flat surface, and then place the rocket snugly over the launch tube. 10. After you have checked to make sure the rocket isn t pointed at anyone, squeeze the bag to initiate the rocket launch. 11. To launch rocket, place hand on bag and then firmly expel the air from the bag. Countdown to Blast Off! 1. Read all directions for the experiment several times. Follow the directions as written. If you are unsure about any part of the activity, ask your teacher for assistance.. Perform only the activities that are suggested by your teacher. Obtain permission prior to working on any modified activity.. Handle scissors or sharp objects with extreme care. Never cut material toward you: cut away from you. 4. Work only with provided equipment or supplies. 5. Notify your teacher immediately if you or a classmate is injured. 6. Children should wear protective goggles during the rocket launch. 7. Keep plastic bags away from your nose and mouth. 8. Keep paper tubes and pointed objects away from everyone s eyes. 9. Launch rockets from designated area. 10. Never aim the rocket at anyone and make sure that the launch is clear of people.
Things to Keep in Mind Make sure your tape is sealed very securely before trying your rocket. Press firmly (do not smack or stomp) on the bag to expel air. Otherwise the bag may break. If you are testing distance you will want to angle your launch tube at about 45 degrees. If you are testing height you will want to place your launch tube at a 90 degree angle. (Be careful while pressing on the bag). Make sure to experiment with the launch compressor and your rocket before recording the data for your trials. Flight Planner Data Collection Sheet (A minimum of 6 launches should be made.) Choose an independent variable (IV) that you can change. Typical IV s might be number of fins, length of rocket, type of material, mass of the rocket. Choose one dependent variable (DV) and make three launches per DV for each IV for a total of six launches.. Typical DV s are: flight duration (seconds), vertical height (meters), or horizontal distance from the launch pad (meters). You may use any of the above examples, or you may come up with your own. Make sure you okay your variables with the teacher before continuing. Calculate an average for each set of three launches per Data Table Independent Variables (IV) (Manipulated) Trial No. Dependent Variables (DV) (Measured) (Describe DV and measurement units) First IV (Describe) 1 Average Second IV (Describe) 1 Average
Evaluation of Rocket Performance 1. Describe your rocket (ex. # of fins, material, lengths, etc.). Which trial produced the best result for each of your independent variables? What effect did the IV have on each of the best DV trials? Why do you think that is?. What recommendations would you make to produce the most effective rocket? 4. What other independent variables should be considered when building a rocket? 5. Graph your results on graphing paper or in Excel. Put the trial number for each IV on the horizontal axis and the DV on the vertical axis. How will you graph your results to see the best correlations? 6. From the graph is there a relationship between the DV and IV? If so, describe the relationship. 7. Based on the graph data, which IV that you chose best shows the correlation to the DV? What s Due? 1. Data Table. Graphs. Evaluation Questions Important Instructor needs to check your rocket and launch system before you leave class on the day of the lab. Instructor needs to check your independent and dependent variables before you leave class on the day of the lab. 4
Rocket and Launch System Compressor Instructions 5