Technology and the Diversity of Limits

In this Evaluate activity, Designing the Fuel, students will construct the rockets that they began testing in the Elaborate activity. They will use the information they learned in the Elaborate activity. They will design and test the amount of two components of a fuel to determine the best amount of each to use. They will then write a letter to Donald Ablestein to explain the tests from both the Elaborate and Evaluate activities.

Materials

For each class of 30 students:

• meterstick or other device for measuring length (see Advance Preparation)
• assortment of different-sized index cards, including 3 × 5 in., 4 × 6 in., and 5 × 8 in. cards
• several sheets of 1/8 in. thick craft foam (see Advance Preparation)
• 1 roll of transparent tape
• glue
• markers (optional)
• pens or pencils of different colors
• 15 pill bottles with snap caps (see Advance Preparation)
• 15 pairs of scissors
• antacid tablets, approximately 120 (see Advance Preparation)
• 15 bottles of water
• 15 100 mL graduated cylinders
• 15 copies of Master 3-8, Fuel Design Report 

Advance Preparation

You can order pill bottles with snap caps online by searching for snap cap pill bottles or snap cap vials. The 13- or 16-dram size should be sufficient. Alternatively, you may be able to get pill bottles with snap caps from your local pharmacy. If necessary, film containers with snap caps will work, but the pill bottles work much better, so make an effort to get the pill bottles if possible.

Craft foam is available in many discount department stores in the craft section or children’s craft section. You may wish to cut the sheets of foam into smaller pieces in advance. Students will use the foam to make the fins for the rockets, so they should not need too much foam.

Fizzing antacid tablets can be bought in bulk packages in warehouse stores or online. We recommend providing each team with about 8 tablets. Students should be aware of this limit before beginning their design plans so that they can plan accordingly. If you use antacid tablets that you purchased in prior years, test them to make sure that they still produce a reasonable amount of gas when placed in water. All the tablets you give students should have been purchased at the same time, as they may lose some of their ability to fizz over time. If students use some new and some old tablets the results may be very different.

The rocket launches for this activity are best done outside, as some water and antacid are left behind when the rockets launch. Plan where to carry out the activity, because students will need a way to approximate how high the rockets travel. The best way to help students measure is to attach metersticks or measuring tape to a wall or tree. Build and test a rocket and your method of measuring before teaching this activity to make sure you understand the setup and the launch of the rockets. You may wish to read the instructions in Step 5 of this teacher’s guide to think about how and where you set up your rocket launch.

Make one copy per team of Master 3-8, Fuel Design Report.

Cautions

Make sure that students are standing back when the rockets launch. The rockets can fly many feet in the air (in experiments at BSCS, they flew approximately 12 feet high), so it is dangerous for students to stand directly over the rockets.

Outcomes and Indicators of Success

By the end of this activity, students will

1. understand how to design and carry out a fair test.

   They will show their understanding by

   • writing out a design for the fair test of both water and antacid
   • conducting the tests according to the plan
   • writing a letter that explains the tests from the Elaborate and Evaluate activities.

2. understand how models can help with technology design.

   They will show their understanding by including in their letters information about the tests done on a simulator.

Getting Started

Have students review the key ideas for all activities in this chapter. You might ask them what they have learned about one of the key ideas. They should also be able to answer all the linking questions leading up to the Evaluate activity. Remind students that in the Elaborate activity they conducted some tests on rocket parts. They should have the results of those tests in their technology notebooks. In this activity, they will continue their rocket design work.

1. Have students retrieve the materials they need to use for the rocket design. Give them a few minutes to discuss how to build the rocket. For your information, students should use a pill bottle as the base and tape an index card around it to make the body of the rocket. They may have to trim the index card so that it fits with the conditions from the Elaborate activity. They can make a nose cone out of the index cards as well. The foam should be used to create fins, which can then be glued onto the rocket body. You may wish to give them an opportunity to decorate the rocket. If so, provide them with markers, but limit the amount of time they can spend decorating. Although it is important to allow students to be creative, the most important part of this activity is the actual design of the rocket, not the decoration of it. If students are having difficulty, you may share as much of this information as you feel they need. Students may come up with other ideas for the rocket. You may allow them to construct the rocket in other ways as long as the rocket meets the conditions from the Elaborate activity and has the pill bottle as the base. Students should not build the rocket yet.

2. Once students have seen the materials, they should design the tests. Remind them that some of the conditions were determined from the simulator tests in the Elaborate activity, so in this activity they will only test the amount of water and the amount of antacid. Have them read the hint. Make sure they know how many antacid tablets they are allowed to use. They can break them into pieces and test less than a whole tablet. For your information, the rockets seem to work best when the pill bottle is about half full of water and between 1/2 and one antacid tablet is used. The results may vary somewhat, but when the pill bottle has too much water, not enough gas can build up to launch the rocket due to space limitations. When the pill bottle has too little water, not enough of the gas can form to create enough pressure to launch the rocket. Students should be testing the amount of water and antacid, so do not share this information with them.

3. Master 3-8, Fuel Design Report, has two graphic organizers to help students report what they will do in the tests. It will also serve as a report for Donald Ablestein. Students should use one organizer for the water test and the other for the antacid test.

4. Students should get your approval before they move on. Make sure that their designs only test one variable at a time and that they keep other variables constant. You may also need to check that they will not use too many antacid tablets with the test designs.

5. Allow students to build the rocket inside. The launches should be conducted either outside or in a room with very high ceilings and paper or plastic on the floor. A multipurpose room with a wading pool “launch pad” may work well. Make sure that students take their technology notebooks and handouts with them to the launch so they can record their results.

6. Once students have results, they should write a letter to Donald Ablestein to explain the tests. Make sure students know to include each of the tasks listed in Step 6.

7. Step 7 is a task that will help with student motivation and thinking about careers. Students should add a few sentences to explain whether or not they would like to continue working for Donald Ablestein and why. Tell them that there is no right or wrong answer to this. In other words, they will not lose points for not wanting to continue the work; however, they do need to explain their choice.

8. After students have completed their letters, they should carry out the Think-Share-Advise-Revise (TSAR) strategy with a partner about the letters. You may need to refer them to How to Use the Think-Share-Advise-Revise Strategy if they need help. Remind them to give their partners constructive feedback that is more informative than “nice job.”

9. Collect the work as you see fit. This activity represents the summative assessment for this chapter.