What child does not gaze at the. STEM activities for upper elementary students. By Joan Gillman

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1 STEM activities for upper elementary students. By Joan Gillman What child does not gaze at the night sky, held spellbound by the awesome sights above? How many times have your students dreamed of going on a rocket ship and visiting the planets in our solar system? To capture this excitement and engage students interest, I have designed lessons that give students the opportunity to experience the joys and challenges of developing straw rockets, and then observing which design can travel the longest distance. The lessons are appropriate for students in grades 4 and 5. I have used the rocket-building unit very successfully with my fifth-grade students. It is such a joy watching my students working diligently on the investigation while at the same time enjoying the challenges the unit presents. Our straw rocket investigations relate to disciplinary core idea PS2.A, as explained in the grade 5 endpoint found in A Framework for K 12 Science Education: Each force acts on one particular object and has both a strength and a direction. An object at rest typically has multiple forces acting on it, but they add to give zero net force on the object. Forces that do not sum to zero can cause changes in the object s speed or direction of motion (NRC 2012, p. 115). Although our experiences are with fourth and fifth graders, the Next Generation Sci- 44 Science and Children

2 ence Standards identify a third-grade standard, 3-PS2 Motion and stability: Forces and interactions, which address performance expectations 3-PS2-1: Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object and 3-PS2-2 Make observations and/or measurements of an object s motion to provide evidence that a pattern can be used to predict future motion (Achieve Inc. 2013, p. 23; see Internet Resources). In addition, a related performance expectation is engineering design 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved (Achieve Inc. 2013; see Internet Resources). The experiences also support the understanding of the crosscutting concepts of patterns and cause and effect. The straw rocket unit fits very well with these standards. In this unit, the students will be working with both controlled and manipulated variables. They will be testing and evaluating each variable to determine the ideal flying design for their straw rocket. Throughout this unit, the students will be actively engaged in the learning process. They will be looking at the flight data they collect. They will be analyzing the results of their straw rocket flights, and they will be redesigning their rockets to improve upon their original design. A Brief History of Rockets To begin this unit, the students look at the history of rockets. From Chinese fireworks to the development of modern rockets, the history of rocket construction is a fascinating story. In the 1860s, the science fiction writer Jules Verne envisioned a spacecraft that could be shot out of a cannon and sent to the Moon. If you go further back in time, the first rockets were actually developed by the Chinese. There is a famous Chinese legend that dates from approximately 1500, which is about an official named Wan-Hu. He attempted to fly to the Moon by tying a number of rockets to his chair and lighting them. The rockets made a huge roar when they exploded. Once the smoke had cleared, there was no trace of either Wan- Hu or his chair. If we jump ahead to the 1900s, we can see the initial development of modern rockets. Much of this development can be attributed to scientists such as Russian physicist Konstantin Tsiolkovsky, American physicist Robert Goddard, and German rocket designer Wernher von Braun. There are some excellent trade books that can be used to help students advance their knowledge of the history of space flight. Two of them The History of Rockets (1999) and Rockets (2008) are written by Ron Miller (see Resources). Students check the length of the straw before adding the clay nose cone and fins to the rocket. How Rockets Work Before the students begin designing and building straw rockets, they need to comprehend what a rocket is and how it works. I introduce the lesson with a brainstorming session. The first question asked is What is a rocket? Student answers have included It s a device that takes people to outer space or It s a large, noisy machine that lifts off the ground with lots of gas and smoke. The next question is usually more challenging: What do you think enables a rocket to fly? Responses have included: It uses lots of fuel or A large explosion lifts the rocket off the ground. Once we ve concluded this session, we re ready to begin discussing the science behind rockets. This unit exposes children to Newton s third law of motion. Newton s third law describes the relationship between the forces that two objects exert on each other. Forces always come in equal but opposite pairs. An easy way to demonstrate this would be with a balloon. If you fill a balloon with air and then release it, air escapes and the balloon is pushed in the other direction. The force exerted by the balloon on air moving out of the balloon is an action force. An equal force, exerted by the air mov- Photographs courtesy of the author October

3 Students calculate the mass of their rocket using a triple beam balance. ing out of the balloon, pushes the balloon forward. This is the reaction force. This activity really excites the children. What child has not tried this same demonstration at home? You can also extend this lesson by making a balloon rocket using a balloon, kite string, a plastic straw, a clear plastic bag, and tape. If there are students with latex allergies, you may want to consider purchasing balloons made from vinyl, foil, or plastic (see NSTA Connections for a description of how to conduct this activity and places to purchase various kinds of balloons). The main feature of a rocket is its ability to expel gas in one direction. When gases shoot out of the back of the rocket, the rocket is pushed in the opposite direction. For every force or action in which the rocket pushes back on exhausted fuel gases, the exhausted fuel gases exert an equal and opposite force or action on the rocket. The reaction force that propels a rocket forward is called thrust. The amount of thrust depends on a few factors, including Students attach fins to the ends of their rockets. the mass and speed of the gases propelled out of the rocket. The greater the thrust, the greater a rocket s velocity. For the rocket to lift off the ground, it must experience more upward thrust than the downward force of gravity. A good trade book I use in the classroom to illustrate these concepts is Simon Bloom: The Gravity Keeper (Reisman 2008; see References). The text discusses gravity, inertia, friction, and Newton s laws of motion. The energy source for the rocket is the straw rocket launcher (see Resources). The cost of the straw rocket launcher can be expensive. An alternative would be to construct your own. If you Google The Ten Dollar Rocket Launcher, it will take you to a site sponsored by the Air Force Association, Hurlburt Field Chapter (398). There, you will find step-by-step instructions for making your own device. To launch the rockets, the straw rocket launcher uses the pneumatic force created by releasing a weighted drop rod in the cylinder. The force of the launch can be controlled by varying the release height of the rod. There are some recommended trade books that can expand the students comprehension of how rockets work. These include How Does a Rocket Work? by Sarah Eason, Rockets and Other Spacecraft by John Fardon, and Master Engineer: Rockets by Paul Beck (see References). Let s Begin the Straw Rocket Investigation In the NSTA Connection, you can find the directions for the straw rocket activities as well as the recording and data sheets. Why should you choose to use straw rockets in the classroom? It s an excellent way to include STEM skills in your curriculum. You ll be combining science, model-building, data collection, design testing, and some math skills in this project. When I begin the building aspects of this curriculum, I show the video Dr. Zoon Presents Straw Rockets made by Pitsco Education. It provides an excellent introduction to building and testing straw rockets. The original Dr. Zoon video has now been replaced with one called Straw Rocket Video (see Internet Resources). After showing the video, I commence the next lesson with the question, How can you design a straw rocket to reach the farthest distance in the path that you expect the rocket to take? Before discussing the rocket s specifications, I spend a few minutes seeing what ideas the students might have for their rockets. Some children have imagined having triangular or square-shaped rockets. Others have described rockets that are similar to the ones at NASA. Once the discussion concludes, we are ready to begin the 46 Science and Children

4 Straw Rockets Are Out of This World formal planning of their rockets. Since we ll be working with specific variables, it s important to review the specifications for the rocket (see NSTA Connection for the direction sheets). The straw length may be cm. There can be 2 5 fins, and the clay nose cone must be 2 cm or less in diameter. Finally, the students select and record three launch angles to test by adjusting the angle mechanism on the launcher. The same rocket will be used for the three different launch angles. Once we have reviewed the specifications, students record their hypotheses and begin planning their rockets. This first part takes the form of a sketch of their rockets. Next, the students begin building their rockets. At this stage, measurement skills become important. Students use rulers to check the length of the straw and the diameter of the nose cone and use a triple beam balance to determine the mass of the rocket. If students are more familiar with a double pan balance, this can be substituted. Attaching fins to the straw body can be challenging. I recommend pairing the students with a partner that has facility with this skill. Since I try to instill in my students the philosophy that we are a community of learners, I encourage the children to help one another. Straw Rocket Testing A student tests the straw rocket launcher in the science lab before bringing it outside. A student records the flight data for her rocket. Once the rockets are designed, built, and measured, we re ready to begin testing the rockets. This can be accomplished outside in an open space. It is possible to do the activity inside, but you will need sufficient space. My student s record for the longest flight was 39 m and 90 cm! Since the students have chosen three different launch angles, they ll have the opportunity to record the distance the straw rocket travels for each of the chosen launch angles. When testing the rockets, choose a day when the weather is fair with little wind. The rocket s mass is very small, so any amount of wind or wet conditions will affect its flight. Before testing the rockets, I recommend securing about 30 meters of measuring tape to the ground. This will enable the students to determine how far their rockets have flown. Don t forget to have the students wear their safety goggles and remain clear of the launch area. The flight path of the rocket can vary greatly depending on its construction, so there is the possibility that it could fly off to the side and hit one of the students. I highly recommend making sure the flight path is clear before the students set off their rockets. Next, have the students bring the recording data sheet, a clipboard, and a pencil so that they can record their rockets flight distances (see NSTA Connection for the data sheets). As the rockets are set off, it s easy for the children to get caught up in the excitement of the activity and forget to record flight distances. A few reminders should help keep them focused on their tasks. Expect to hear shouts of joy as the rockets soar through the air. There will also be some disappointment, since October

5 not all rockets will fly well. You can reassure the students that they will have another opportunity to improve their rocket designs. The next step is to analyze the results of the rockets flights (see NSTA Connection for the analysis sheets). At this point, the only variable tested was the launch angle. The students haven t tried changing the rocket designs to see how that would affect the flight distance. It s possible to set up a more systematic approach using controlled and manipulated variables. In the initial investigation, the controlled variables were the length of the straw body, the number and shape of the fins, and the size of the nose cone, while the manipulated variable was the launch angle. Straw Rocket Building Continued In the following investigations, the students can manipulate one of the previously controlled variables while keeping the other ones controlled. For example, the first manipulated variable could be the length of the straw body. Students would design, build, test, and record data for the flights of a 10 cm, 15 cm, and 20 cm straw rocket. At the same time, the number and design of the fins would have to remain the same, the size of the nose cone would need to be uniform, and the launch angle would have to stay at 45 degrees. By keeping the other variables controlled, students would be able to interpret how each manipulated variable affects the flight of the rocket. The next manipulated variable could be the number of fins, while the final manipulated variable could be the size of the nose cone (see NSTA Connection for the manipulated variable direction sheets). At the conclusion of the unit, the students should be able to come to a consensus on the type of straw rocket that goes the farthest. Some Misconceptions When students are introduced to the rocket building and launching topics, there are a few misconceptions or misunderstandings they can exhibit. Initially, the children become fixated on the aesthetic appearance of the rockets rather than thinking about what qualities might enable the rockets to fly the longest distance. This misunderstanding usually becomes less of an issue once the students analyze their data after their rockets first flights. A second area of difficulty involves accurately measuring and weighing their rockets. Some students use the wrong side of the ruler and report measurements in customary units rather than metric ones. Finally, the use of a triple beam balance or double pan balance to find the mass of the rocket can be challenging. Straw Rocket Building Directions Here are some easy-to-follow directions for building the straw rockets. 1. Take one of the straws and cut it so that the length is between 10 and 20 cm. 2. On an index card, draw one of the fins you will be attaching to the rocket. Cut out the fin and use that as a template to make the additional 1 4 fins. 3. Attach the fins to the straw rocket using transparent tape. 4. Construct the clay nose cone 2 cm or less in diameter. 5. Place the clay nose cone ½ cm into the end of the straw Science and Children

6 Straw Rockets Are Out of This World integrate STEM skills into the curriculum while getting students excited about the learning process. n Joan Gillman (joan.gillman@calhoun.org) is a middle school science teacher at The Calhoun School in New York City. A preliminary sketch of a rocket with measurements. Young children can also find it challenging to analyze data and write conclusions based on their findings. This is a vital skill, one that they will be using throughout their lives. In the fall, I frequently model how to write a lab report. Once the rocket building unit commences, students have begun to develop some facility with this skill. This becomes especially important because they will need to examine the results of their rockets flights and then manipulate the variables so that they can enhance their rockets ability to fly. Lesson Evaluation In the straw rocket unit, I used a variety of methods to assess student learning. During one class, students were asked to plot the results of the previous day s rocket flight. First, I looked to see that the students had accurately noted the distances using the metric system. Next, I observed the students to see if they were struggling with the printed directions. I also checked whether or not they correctly measured and built their rockets using metric measurements and if they had developed more facility with use of the triple beam balance or double pan balance. Next, I evaluated how well the students could articulate what they were doing. Finally, I wanted to see if the students could build a more successful second rocket based on the results of their first model. I have developed a rubric to use when evaluating the students performance in this investigation (see NSTA Connection). The straw rocket unit can be an exciting and educational experience. When I ask my students at the end of the year what their favorite activity was, the straw rocket unit is usually the first one that comes to mind. I personally enjoy teaching this unit because it s a great way to References Achieve Inc Next generation science standards. www. nextgenscience.org/next-generation-science-standards. Beck, P Master engineer: Rockets. Charlotte, NC: Silver Dolphin Books. Eason, S How does a rocket work? New York: Gareth Stevens Publishing. Fardon, J Rockets and other spacecraft. United Kingdom: Copper Beach Publishers. National Research Council (NRC) A framework for K 12 science education: Practices, crosscutting concepts, and core ideas. Washington, DC: National Academies Press. Prentice Hall Science explorer: Astronomy. Upper Saddle River, NJ: Prentice Hall. Reisman, M Simon Bloom: The gravity keeper. New York: Puffin Books. Internet Resources NGSS Table: 3-5-ETS1 Engineering Design NGSS Table: 3-PS2 Motion and Stability: Forces and Interactions NGSS Table: 3-PS2-3 Motion and Stability: Forces and Interactions Pitsco Education: Straw Rocket Video Resources Asyby, R., and R. Hunt Rocket man: The mercury adventure of John Glenn. Atlanta: Peachtree Publishers. Miller. R The history of rockets. New York: Franklin Watts. Miller. R Rockets. Minneapolis: Twenty-First Century Books. Otfinoski, S Rockets. New York: Benchmark Books. Sobey, E Rocket-powered science: Invent to learn! Create, build, and test rocket designs. Culver City, CA: Good Year Books. NSTA Connection Visit for the lesson materials. October