Craft Rocket Challenge #1

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Objective

Students will be able to build a model rocket using household craft material and determine the altitude that their rocket was able to achieve.

Big Idea

Launching a rocket is good, building a rocket is better, building a rocket from scratch is best.

NGSS Background

This lesson is based on California's Middle School Integrated Model of NGSS.

NGSS Performance Expectation (PE): (MS-ETS1-1) Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

Science and Engineering Practice SP1 Asking Questions and Defining Problems. Students are required to build a rocket from household craft material that uses an 'A' Model Rocket Engine and can reach an altitude of 100 meters. Theses design criteria require that students understand the problem and are sufficiently versed in rocket construction plans and applicable scientific principles.

Disciplinary Core Ideas (DCI): ETS1.A Defining and Delimitating Engineering Problems - The more precisely a design task's criteria and constraints can be defined, the more likely it is that the designed solution will be successful. Specification of constraints includes consideration of scientific principles and other relevant knowledge that are likely to limit possible solutions.

Crosscutting Concepts (CCC) Influence of Science, Engineering, and Technology on Society and the Natural World - The uses of technologies and any limitations on their use are driven by individual or societal needs, desires, and values; by the findings of scientific research; and by differences in such factors as climate, natural resources, and economic conditions. 

This lesson allows students to build a model rocket from common household materials using a precise set of directions. The criteria for this build is that (a) it must be made from scratch (except engine), (b) reach an altitude of 100 meters, and (c) successfully deploy its flight recovery system (streamer of parachute).

I spend about three days walking the students through the building process step-by-step until they have reached a point where they can work independently. They work in groups of 3-4 students to build the rocket. In their Interactive Science Notebooks they have to create a chart that determines their rocket's altitude using a NASA Altitude Tracker. To calculate altitude the students have to stand a set distance from the rocket launch and measure the angle from that point.

During the construction process I refer back to Newton's 2nd Law (force is dependent on the mass and acceleration of an object). I explain to them that the lighter they can make their rocket the greater the acceleration will be, which results in a higher altitude. By explaining this to the students they are less apt to waste supplies (saves budgetary money). 

The students will build a more complicated version of this rocket with Craft Rocket Challenge #2. They follow all the same basic building parameters with the added complexity of computing the rocket's acceleration (Newton's 2nd Law: acceleration = Force/mass) by looking up the average Newtons of force on the rocket engine (force) and weighing the rocket (mass). 

How To Build The Rocket Tube

60 minutes

The rocket tube is the basis for building the rocket. The better the tube the better the rocker will perform.

1) Start with a 3/4" X 16" blank dowel. The diameter of the wooden dowel was chosen because it is approximately the same diameter of a model rocket engine. I purchased several longer sections of dowel (4ft) and cut them to size so as to have multiple dowels (one per group). 

2) Wrap in wax paper. You will wrapping glue-soaked paper around the wooden dowel and will need to remove the dowel once the paper has dried.

3) Cut a section out of a brown paper bag. The section of paper bag should allow several wraps around the wooden dowel. The more layers that can be wrapped around the wooden dowel the stronger the tube will be. Make sure that the wooden dowel is able to stick out at either end once the paper has been wrapped around the dowel.

4) Make a solution of white glue and water. I don't use any specific measurements, just add enough white glue so that the solution has a light syrup consistency.

5) Keep the solution more on the watery side.

6) Dip the brown paper bag into the white glue/ water solution. The wetter the paper bag is the stronger it will be while at the same time the longer it will take to dry.

7) Wrap the wet paper bag around the wooden dowel and allow to dry overnight. I teach in a very arid climate so things dry quickly, you may need to adjust drying times in humid environments. The final edge of the paper bag will curl up as the paper dries. You can see that happening in the photo below. I run a bead of white glue along the edge to seal it. You can also add a few strips of tape to help the edge stay in place as it dries.

8) Carefully remove the dowel from the newly formed rocket dude. You may use another dowel of the exact same size to ream the old dowel from the inside of the rocket tube.

9) You now have a rocket tube suitable for flight. I have my students trim the edges flat.

How To Build The Nose Cone And Fins

60 minutes

The nose cone will determine the quality of flight. Designing a nose cone with a pointy edge versus a rounded edge has a substantial effect on the altitude of the rocket. I have my students research the difference and design a nose cone of their choosing.

1) I pass out scrap of styrofoam and sandpaper and have my students shape a nose cone. The styrofoam dust makes a mess. We spend about 15-20 minutes cleaning up the styrofoam dust.

 

2) Cut a small paper clip into a 'U' shape, dip the ends into craft glue and insert into the bottom of the nose cone, allow to dry overnight. Tie a length of rubber band or string to the paper clip loop. This will keep the nose cone from flying away once the rocket ejects its parachute. The other end of the rubber band needs to be glued to the inside of the rocket tube, near the top of the rocket.

As with the nose cone, the fins have a large effect of the rocket's flight. I have my students research rocket fins and design one of their own choosing. I have found 3 or 4 fins to be the ideal amount.

 

4) Attach the rocket fins to the rear of the rocket tube.

To keep the rocket stable during lift-off, a guide tube will need to be installed.

 

5) Cut a small length of plastic straw (1 inch) and glue it parallel to the rocket tube, slightly above the fins.

 

How To Build The Flight Recovery System

60 minutes

For a rocket of this weight a full parachute is not necessary, as it adds weight. I explain it using Newton's 2nd Law - force is determined by mass and acceleration. More mass causes less acceleration, which results in a lower altitude. I have my students make a streamer out of a plastic grocery bag.

1) Cut a strip about 4" wide by 20" long from a plastic grocery bag. Tie the steamer to the rubber band connecting the nose cone to the rocket tube. Note how the rubber band is glued to the inside of the rocket tube.

How to build the engine mount

20 minutes

The engine mount keeps the model rocket engine in place as the rocket fires it's thrust to both lift the rocket and eject the streamer.

1) Open up a large paper clip and fold it as straight as possible. Use wire cutters to trim the paper clip about 1/2" longer then a model rocket engine. Bend the ends of the paper clip over the edges of the rocker engine as seen in the photo below.

 

2) Poke one bent end of the paper clip into the rocket tube. Position the paper clip so that the bottom bent end extends approximately 1/4" aft of the rocket tube. Secure the paper clip in place with clear packing tape.

 

Student Activity

20 minutes

For the student activity I place the students in groups (nine total groups). Each group is responsible for building one rocket. Each group also builds a NASA Altitude Tracker with yarn, washer, and a brad. To keep all the groups engaged they have to measure the altitude of all rockets and compute an average. The chart is built in the student's Interactive Science Notebook. 

I mark out dashes on the grass at 15 meters and 30 meters from the launch site to aid in the student altitude measurements.

Student Work Sample