Build a Machine to Lift Water

Background Information for Teachers

This section contains a quick review for teachers of the science and concepts covered in this lesson.

Global Problem Solvers: The Series pits a group of teenagers against some tough real-world engineering challenges. You can use this video series to help frame engineering problems for your students and show how engineers can have real-world impact and help people. Watch this trailer for an introduction to the first season of the show, which focuses on problems with village water supply in Malawi:

You can connect the series to your students' lives. Do they know where their water comes from? What would happen if a natural disaster cut off their town's water supply? These are the types of challenges that real engineers tackle to help improve people's lives and make the world a better place. The Global Problem Solvers use a process called social entrepreneurship to tackle problems. You can read more about the teen Global Problem Solvers, their "superpowers," and their problem-solving process in 5 Reasons Global Problem Solvers: The Series Will Inspire STEM Interest in Your Students.

In this project, your students will be challenged to build a prototype of a device that can manually lift water. Throughout history (and well before electricity was invented), humans have come up with various ingenious ways to move water from one location to another. Your students might be familiar with manual pumps or wells that use a rope and bucket to lift water out of the ground (Figure 1). But what about more obscure devices like an Archimedes screw or Persian wheel? (Figure 2)?

This is an open-ended project, and there are many different options for what your students can build. They could build a version of one of the historical devices shown above or come up with something completely new. Figure 3 shows a few examples built with readily available materials.

Global Problem Solvers: The Series is based on a 7-step process of social entrepreneurship (PDF). This process is similar, but not identical, to the engineering design process that you may already be familiar with. The worksheet provided for students in this lesson is tailored to fit this specific project and adds the business aspects of social entrepreneurship to the engineering design process.

Additional Background Links

• Global Problem Solvers: The Series, Cisco
• Engineering Design Process, Science Buddies

Here are all seven episodes of the first season of Global Problem Solvers: The Series:

Prep Work (15 minutes)

• If you do not have a sink in your classroom, you will need to fill some large containers with water and bring them to your room.
• Prepare a price list for all the materials you will be making available to students. Students will use this information to calculate the total cost of their prototype. You can make up reasonable "costs" for recycled items like plastic bottles or other materials students bring from home.

Engage (1 hour)

Watch season 1 of Global Problem Solvers: The Series as a class or assign the episodes for students to view individually as homework. The season consists of seven episodes, each 3–5 minutes long. You can start watching online on the series website or these individual episodes from season 1.

After watching, have your students discuss their reactions to the show as a class. Students can record their individual thoughts on the student worksheet. For example, would they have done anything differently if presented with the same problem?

Connect the discussion to water resources in your community. Do students know where their water comes from? Is their home connected to a public water supply or a well? Does the water come from a nearby lake or river? What would happen if there was a natural disaster, like a big storm that knocked out electricity to the area, a chemical spill into a lake, or a water tower getting knocked down by an earthquake? Answers will vary depending on how water is supplied in your region and may even vary from student to student. For example, a student whose home relies on an electric well pump might lose water if the power goes out, but a student whose home is connected to a public water supply from a water tower (which relies on gravity to provide water pressure, not electricity) might not—at least in the short term.

Explain that the challenge is for students to be engineers and design a solution to a potential real-world problem in their area. They will design a device that can manually lift water in the event of an emergency when the regular water supply is cut off. They will build a working prototype of their device and come up with a basic business plan for how it could be used in the real world.

Explore (4 hours)

Break your students into teams of 3–4. Global Problem Solvers: The Series is based on a seven step social entrepreneurship process which incorporates the key elements of the engineering design process. Guide your students through these processes as they work on the project. They can use the student worksheet a guide and place to document their progress. Note that these processes are iterative: you might go back and forth between steps and do some steps more than once. This is OK!

1. Define the problem. Before they start building something, students need to figure out exactly what problem they are trying to solve. First, it might help to discuss something that might seem obvious. Why do people need water? How long can we go without drinking water, using it to cook or do laundry, or taking a bath/shower? Why is it an emergency if people don't have access to fresh water? As you discussed in the Engage section, what are some different ways people get water to their homes? How could those water supplies be cut off?
2. Do background research. This step can be done in class or assigned as homework. Your students should do research on different ways people have lifted or pumped water from one location to another. As shown in the teacher background section, there are many clever ways that ancient and pre-industrial civilizations have done this. If needed, you can give your students hints about some of the devices (e.g., Archimedes screw) that they might have trouble finding on their own.
3. Design a solution. After doing background research, some students might get excited about a particular idea or want to build the first design that pops into their head. Not so fast! Engineers need to be more careful and systematic than that. Break this part of the process down into sub-steps:
   1. First, show your students the materials they will have available to build a prototype, as well as the price list you came up with. Explain whether they will be allowed to bring materials from home and how costs will be assigned to those materials.
   2. Specify requirements: students need to clearly define requirements that their design must meet. How will they determine if a design is "good"? For example:
      1. How fast can it lift water? How could they measure that (e.g., in cups per minute)?
      2. Should the design be portable or fixed in one place?
      3. How durable (able to operate for a long time without breaking) should it be?
      4. How much should it cost?
      5. How many people should it take to operate the device?
   3. Specify constraints: students also need to be aware of practical limitations on their design. You might set some of these as the teacher. For example:
      1. How much time do they have to build it?
      2. Are there any materials they do not have available?
      3. What real-world limitations would there be on its use?
   4. As a class, discuss the requirements and constraints that different groups came up with. Agree on a shared list of metrics that can be used to compare different designs, such as cost, device size (e.g., measure length × width × height), and volume of water lifted in one minute.
   5. Brainstorm solutions. Based on their background research, the materials they have available, and the requirements/constraints they came up with, now students can start thinking about what they can build. Encourage students to individually make at least two sketches of different devices they could build to lift water. This is the creative phase—don't get too bogged down in details or worrying about whether an idea will work.
   6. Choose the best solution. Within each group, students will need to compare their designs and agree on what to build. Remember that the process is iterative. They don't "have to" pick one of the original designs. They might merge two designs or modify one design based on someone else's ideas. After agreeing on a design, they should make a list of all the materials they will need to build it, and make a sketch in their worksheets.
4. Build and test the solution. That was a lot of work before they even get to start building! Now, after agreeing on a design, each group should start building and testing a prototype. Again, this process will be iterative. They might discover as they start building that their design doesn't work like they thought it would "on paper." Maybe it isn't sturdy enough and falls apart right away, or maybe it falls apart under the weight of the water when they start testing it. It is OK to go back and make improvements or changes to the design. Real engineers rarely get things right on the first try!
5. Measure results. After each group has finalized their prototype, they should evaluate it based on their requirements and the metrics you agreed upon as a class. Does it meet all of their original requirements? Do they need to adjust any of the requirements because they were unrealistic?
6. Make a business plan. As you saw in Global Problem Solvers: The Series, it isn't enough to just build a single prototype of a machine. To have a real-world impact, you need a plan for how the machine will be mass-produced, sold, and used. Ask each group to come up with a business plan, inspired by what they saw in Global Problem Solvers: The Series. Your expectations for this plan may vary based on the age of your students. For example:
   1. For younger students:
      1. Come up with a name and design a company logo.
      2. Design a poster marketing their device.
      3. Calculate how much their device costs based on the materials they used and the price you provided.
      4. Explain who they will sell their device to. For example, would individual people buy the device for their homes, or is the device something businesses or government officials would buy?
   2. Older students may also want to develop a more advanced plan. This could include the items listed above, as well as:
      1. What materials they would use to build a real full-scale device.
      2. What local companies or government agencies they would approach for assistance or funding.
      3. A "sales pitch" that explains why their device is the best.
7. Communicate results. Each group should prepare a brief 3-5 minute presentation about their design for the rest of the class. Again, your expectations for the level of detail in this presentation may vary based on your students' age. The presentation should cover both the physical prototype and the engineering design process (e.g., challenges they faced, changes or improvements they made to their design) as well as the business plan developed in step 6. The presentation should include demonstrating the prototype for the class. Additional visual materials (posters, slides) can also be used.

Reflect (1 hour)

1. Let each group give their presentation to the class. Allow other students a chance to ask a few questions after each presentation.
2. Optionally, you can give awards in different categories, such as:
   • Device that lifts the most water the fastest
   • Most creative or original device
   • Best business plan/sales pitch

Assess

Assess each group's project using this rubric (DOC).

Lesson Plan Variations

• Can your students motorize their designs? For an example, see this video. You could also automate the designs using an Arduino or Raspberry Pi.