Count the Seconds

Materials

Handouts (1 per student)

• Count the Seconds Student Handout Part 1
• Count the Seconds Student Handout Part 2

Tools (1 per group)

• Hole punch
• Scissors
• Stopwatch

Try to provide a couple different types of items from each of the categories below.

Background Information for Teachers

The Tech Challenge

Image Credit: The Tech Museum

This lesson can be used to prepare students for the 2022 Tech Challenge: Kinetic Commotion, presented by Amazon. This lesson will

• Give students experience with building simple machines.
• Familiarize them with stored energy and energy transfer.
• Introduce students to triggers (release mechanisms).

Vocabulary

For more tips on vocabulary and common engineering terms see The Tech Interactive's Tech Tip: The Language of Engineering.

• Energy: The capacity to do work; appears in many forms, all of which are either kinetic or potential.
• Stored energy: Captured energy produced at one time for use at a later time.
• Energy transfer: The conversion of one form of energy into another, or the movement of energy from one place to another.
• Failure point: A place where the design or system failed.
• Gravitational potential energy: Potential energy created by increasing height.
• Kinetic energy: Energy of motion, includes heat, sound, and light (motion of molecules)
• Optimal design: The design or device that best meets the criteria and constraints.
• Optimization: The process of iterating, refining and making trade-offs until a solution is found that best meets the criteria within given constraints.
• Potential energy: Energy that is stored and held in readiness; energy of position (gravitational or elastic potential energy); or chemical potential energy (e.g., fossil fuels, electric batteries, and food consumed).
• Trade-off: A situation in which you must choose between or balance two things that are opposite or cannot be had at the same time.
• Trigger: A built-in mechanism that releases the stored energy in a device.

Resources and References

1. The Tech Challenge
2. The Tech Interactive's Tech Tip: The Language of Engineering.
3. Innovator Mindset Tech Tip (PDF and Video), The Tech Interactive

Prep Work

Lesson Preparation

1. Collect, organize and set up materials.
   • Create materials kits for teams or set up materials at a central location where students can browse and choose the items of interest to them.
2. Print the Student Handouts: Count the Seconds Challenge Part 1 and Part 2 for each student. These tools can be used for data collection throughout the challenge.
3. Build a solution (or solutions) yourself, with other educators or kids you know. This will give you practice with the materials and tools in order to anticipate student questions.

Lesson Instructions

Frame the Challenge

Define the Problem (10 min)

1. Ask students to think about what they know about tools that track and signal time. Ask them what manual or mechanical timers they might have seen before. Inquire:
   • When do you have to set a timer? What do you use?
   • How would you keep track of time if you didn't have electricity?
   • How do devices signal or tell you that time has passed?
2. Students may notice items around their home that do not use electricity to tell time (i.e., hourglasses or other timers in board games). They may also think of simple historical examples, like pendulums. (See Real-world and Historical Examples below for more inspiration.)
3. Explore with students what they might need to keep track of or signal time, i.e., something that moves, changes, or reduces to indicate when a time is up.
4. During this initial discussion, point out which examples mentioned by students use stored energy and energy transfer.
   • Review the definitions and examples of these concepts in the Student Handout: Count the Seconds Challenge Part 1.
   • Note that many of the historical examples start with stored energy (i.e., captured energy produced at one time for use at a later time.)
   • For example: When the weights in a grandfather clock are pulled to the top they have stored energy (gravitational potential energy) to power the clock and move the pendulum. Similarly, sand at the top of an hourglass and water held at the top of a water clock have gravitational potential energy and subsequently fall through the holes below.
   • Energy transfer happens when the energy stored in the weights moves on to the pendulum, and then the hands of the clock.
   • Explain that storing energy is similar to storing other things in the real world. For example: If I store one liter of gasoline in my gas tank, my car can only run so far. Similarly, the amount of stored energy in their timers can vary depending on other factors. Let students know they will have a chance to experiment with stored energy throughout the design challenge.

Real-world and Historical Examples

During your initial discussion students may mention some of these examples of real-world and historical timers and clocks.

• Shadow clocks and sundials
• Hourglasses
• Water clocks
• Candle clocks
• Pendulums
• Congreve rolling ball clocks
• Various gear-based mechanical clocks and watches

The images and background information of these real-world examples can serve as inspiration throughout the lesson.

Image Credit: The Tech Museum

Introduce the Design Challenge (5 min)

1. Introduce the design problem, criteria and constraints. Distribute the Student Handout: Count the Seconds Challenge Part 1.

2. As you review the criteria, make sure students understand a variety of simple machines.
   • It may be useful to refer back to the examples from the initial discussion and point out how they used simple machines.
   • For example: An hourglass has an inclined plane, or the gears in many clocks are an example of wheels and axles.
3. In addition, review the concept of stored energy and how it can be used to power their timer. It may be useful to refer to some of the examples provided previously (i.e., sand in the top of an hourglass, weights in a grandfather clock).
4. Once students understand the criteria, clarify the design process and address any questions students have.
   • Students will test their devices by timing them with their stopwatch.
   • They do not need to determine the amount of time that their device will track until they start building. Instead of starting with a goal, they should develop one as they see how their prototype performs.
   • Longer periods of time might be more difficult for some of these early prototypes. It might be useful to let students know that their timers can track times of 10 seconds or less.
5. If you have not already done so, group students into teams of two to four.
6. It may be useful for teams to have some space to build (vertically as well as horizontally). Some ideas may involve going from a table to a floor or spreading out over a larger space.
7. Note: A 15-20 minute time limit is suggested for this first round of prototyping.

Design Challenge Part 1

Prototype (Build and Test) (20 min)

1. Set a stopwatch to track the time remaining.
   • Give students occasional reminders on time, criteria, and constraints to help them monitor their own progress.
2. During the prototyping time, walk around and support teams.
   • Help students focus on the process, rather than on the success of their designs. If their design fails, ask them how many things they have tried, what they notice about what isn't working, and what they might try next.
3. Ask open-ended questions to encourage students to reflect on their process.

4. Encourage teams to test while they build.
5. Encourage them to collaborate with each other and use the Student Handout: Count the Seconds Challenge Part 1 to take notes on their iterations.

Quick Share (10 min)

At the end of the time limit, teams stop even if they haven't been able to build or complete something.

1. This pause in the prototyping is an opportunity for teams to share their progress with each other and to be inspired by the approaches other teams are taking.
2. This sharing is designed to be quick so teams can focus on how their device is intended to work and the next steps they plan to take.
   • Have all of the teams stand up in a large circle. Give each team 30 seconds to demonstrate and share the highlights of their device, including how their devices store and transfer energy.
3. Encourage students to give each other positive feedback on their designs by telling the other teams one thing they liked or noticed.
   • Teams can mention how others' ideas are inspiring them to add to their own designs.

Design Challenge Part 2

Introduce New Criteria (5 min)

1. Let students know that you will be introducing a new criteria based on real-world constraints.
   • Most clocks and timers need to be able to be set as well as operate without a human to continually power them. So, students will need to include a trigger that releases the stored energy and starts their device.
2. Review the previous criteria and introduce the new criteria. Distribute the Student Handout: Count the Seconds Challenge Part 2.

3. As part of the previous criteria, teams should have determined the amount of time they want their timer to track. Consistency can be measured by trying to achieve this goal three times in a row.
4. Once they have met the initial criteria they can add in the new criteria of activating their device with a trigger.
   • Review the concept of triggers with students. (See the information included in Student Handout: Count the Seconds Challenge Part 2 for some examples.)
   • Remind them that:
     • A trigger is a release mechanism that starts your device.
     • Triggers are used to release the stored energy in your system.
     • A trigger allows your device to be ready, but also to delay starting until it is activated. (Pulling away the block that keeps a ball from rolling down a ramp.)
   • Have a few teams share what source of stored energy they have in their devices and where energy is transferred in their system. Ask teams to begin thinking about how they might use a trigger to initiate the release of the stored energy.

Prototype (Build and Test) (15 min)

1. Iteration is an important part of the design process. Provide students time to revisit and revise their devices and triggers based on their testing, feedback, and observations of other team's designs.
2. Once again, teams should use this time to build, test, and reflect.
3. Teams that have met the initial criteria should add in the new criteria just introduced.
4. During the prototyping time, walk around and support the teams.
5. Use open-ended questions to encourage students to focus on the process:

Share Solutions (15 min)

1. At the end of the time limit, teams stop even if they haven't been able to complete their design.
2. Have each team take turns demonstrating their device and sharing their process.
3. Keep the sharing simple and focused on what they did and why.
4. Possible Sharing Questions include:
   • Tell us how your design works (including how your device stores and transfers energy).
   • What did you adjust/change as you built?
   • What would you change if you had more time?
5. Have students give each other positive feedback on their designs. Encourage them to tell the other teams one thing they liked or noticed.

Debrief (5 min)

1. After students share their solutions, bring the conversation back to the engineering concepts and what they learned.
2. Lead a short debrief with some of these questions.
3. Possible Debrief Questions include:

   Design Process

   • What did you notice about the different prototypes (similarities and differences)?
   • What did you notice about the process to improve the reliability of your device?

   Science Concepts

   • Where did you notice simple machines used in the devices?
   • When did the devices have potential energy and when did they have kinetic energy?
   • How did the devices store and transfer energy? What did you notice and wonder about how energy transferred from one object to another?
   • How did the use of a trigger change the devices?