Handheld Water Bottle Rocket & Launcher

Transcription

1 Handheld Water Bottle Rocket & Launcher Category: Physics: Force and Motion Type: Make & Take Rough Parts List: Rocket Launcher: 1 3/8 One- hole rubber stopper 2 Valve stems, from an inner tube 4 Small zip ties 10 Clear tubing, with 3/16 inner diameter & 5/16 outer diameter 5 ¾ thick- walled PVC pipe 27 ½ PVC pipe (horizontals) 2 ½ x 6 PVC pipes (verticals) 2 ½ T couplings, non- threaded 1 Plastic bottle, better to use soda bottles since they re made for presssure Rocket: 1 Plastic bottle 2 Pieces thick paper or cardstock Tools List: PVC cutter PVC cement glue Scissors Utility knife Bike pump Side cutters Hot glue gun Safety note: Water rockets should only be launched in large open areas, away from structures or other people, in order to prevent damage to property and people. Water rockets can fly more than 50 feet, so do not launch the rockets indoors! The rockets are lightweight and pose no real hazard as they fall but they do have a lot of water inside of them and are moving fast as they leave the launcher so observers should stand back when the rocket is being pumped

2 How To: Rocket Launcher: Cut the ½ PVC into one 3, one 10, and one 14 piece. Put glue around the inside of the 5 x ¾ PVC pipe. Leave 1 of clearance from one end to the edge of the glue. Push the 14 PVC pipe into the 5 PVC pipe. Leave about 1 of space from the top. Layout the PVC pipes as shown. Glue all the T couplings to the PVC pipes. Cut the valve stems off an old inner tube.

3 Remove all the rubber from the valves. Also remove the valve stem core from one valve (not shown). Twist the coreless valve stem through the hole of the rubber stopper.rubber stopper. Stop when the rubber stopper meets the end of the treading on the valve. Push the non- threaded ends of the valve stems into each end of the clear tubing. Wrap zip ties around the valve stem and tubing on each end. Insert the end without the rubber stopper through the front end of the launcher. Push it all the way through the launcher.

4 Connect the valve stem to a bike pump. Fill ¼ of a bottle rocket with water and push it hard onto the rubber stopper. Take the water rocket outside. Pump the bike pump until the bottle rocket blasts off! Rocket: Cut three fins from one piece of paper. Make them any shape and size you think will make the rocket fly straight and far. Fold one edge of each fin.

5 Glue the fins to the top of the bottle. Roll a sheet of paper into a cone and glue it onto the bottom of the bottle. Connect the rocket to a launcher and watch it fly! Fine Points: Cement glue dries very fast! Have all the pipes ready to connect prior to applying the glue. Make sure the T- couplings are aligned with each other. Metal clamps may be used instead of zip ties. Experiment with filling the bottle with different levels of water. Different sizes of bottles can be used as long as they have a tight fit on the stopper. Concepts Involved: The accelaration of an object is directly proportional to the force acting on it. This means the bigger the force, the bigger the acceleration. For every action there is an equal and opposite reaction. Focus Questions: 1. Does the launcher work without water in the rocket? 2. Which bottles launch higher small or large bottles? 3. What volume of water gives the highest flight? 4. What could be changed to make the rocket fly further?

6 Elaboration: The handheld bottle rocket launcher is a simple way to show the power of air pressure. A bike pump is used to build up pressure to a maximum capacity. The pressure will continue to build with every pump you make, since you re increasing the amount of air in a closed system. The pressure will be released when the rubber stopper can no longer hold the bottle in place. As with all rockets, this one goes forward by throwing something back. Most rockets throw back hot gas from rapid combustion, but this one throws back water. The water is pushed out by the pressurized air on top of it. This is the action. As the water goes back, the rocket receives an equal and opposite force forward. This is the reaction. The amount of water that is used is critical to the performance of the rocket. If too much is used, there is no space for air, and so the water will not be pushed out. Also, if there is too much water, the rocket will be heavy and harder to get going (acceleration is inversely proportional to mass, that is, the bigger the mass, the smaller the acceleration.) If no water is added, only air is pushed out upon release, which is much lighter, so the rocket doesn t get as much of a push. In between there is the maximum amount: you can figure out what this amount is by trying all different levels. The size of the bottle that is used will also affect the distance the rocket will fly. Bigger bottles will hold more air and water, giving the possibility of more thrust, but they ll also be heavier and encounter more air resistance. Again, you can find out which is best by trying it. Make sure all the other factors and variables are the same: fin and nose cone shapes, amount of water, amount of pressure, direction of launch, etc. Good science is good fun! Links to k- 12 CA Content Standards: Grades k- 8 Standard Set Investigation and Experimentation: Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other strands, students should develop their own questions and perform investigations. Grades k- 12 Mathematical Reasoning: 1.0 Students make decisions about how to approach problems: 1.1 Analyze problems by identifying relationships, distinguishing relevant from irrelevant information, sequencing and prioritizing information, and observing patterns. 1.2 Determine when and how to break a problem into simpler parts. 2.0 Students use strategies, skills, and concepts in finding solutions: 1.1 Use estimation to verify the reasonableness of calculated results Apply strategies and results from simpler problems to more complex problems. 1.3 Use a variety of methods, such as words, numbers, symbols, charts, graphs, tables, diagrams, and models, to explain mathematical reasoning. 2.5 Indicate the relative advantages of exact and approximate solutions to problems and give answers to a specified degree of accuracy. 3.0 Students move beyond a particular problem by generalizing to other situations: 3.1 Evaluate the reasonableness of the solution in the context of the original

7 situation. 3.2 Note the method of deriving the solution and demonstrate a conceptual understanding of the derivation by solving similar problems. 3.3 Develop generalizations of the results obtained and apply them in other circumstances. Grade 2 Standard Set 1. Physical Sciences: The motion of objects can be observed and measured. 1.a Students know the position of an object can be described by locating it in relation to another object or to the background. 1.b Students know an object s motion can be described by recording the change in position of the object over time. 1.c Students know the way to change how something is moving is by giving it a push or a pull. The size of the change is related to the strength, or the amount of force, of the push or pull. 1.d Students know tools and machines are used to apply pushes and pulls (forces) to make things move. Grade 3 Standard Set 1. Physical Sciences (Energy & Matter): 1.c Students know machines and living things convert stored energy to motion and heat. 1.d Students know energy can be carried from one place to another by waves, such as water waves and sound waves, by electric current, and by moving objects. Grade 8 Standard Set 2. Forces: Unbalanced forces cause changes in velocity. 2.a Students know a force has both direction and magnitude. 2.c Students know when the forces on an object are balanced, the motion of the object does not change. 2.e Students know that when the forces on an object are unbalanced, the object will change its velocity (that is, it will speed up, slow down, or change direction). 2.f Students know the greater the mass of an object, the more force is needed to achieve the same rate of change in motion. Grade 9-12 Physics Standard Set 1. Motion & Forces Newton s laws predict the motion of most objects. 1.b Students know that when forces are balanced, no acceleration occurs; thus an object continues to move at a constant speed or stays at rest (Newton s First Law). 1.d Students know that when one object exerts a force on a second object, the second object always exerts a force of equal magnitude and in the opposite direction (Newton s Third Law) 1.f Students know applying a force to an object perpendicular to the direction of its motion causes the object to change direction but not speed.