SWBAT design an initial plan for the machines based on the task: popping a balloon using at least 3 simple machines.

This is the first step in completing the Rube Goldberg Design Challenge.

5 minutes

*Teacher Tip: This lesson begins the process of engineering. Students have developed initial designs based on the given task (pop a balloon using 3 simple machines). Students will need supplies for this portion of the project. I always provide the following materials: ramps, carts, balloons, push pins, masking tape, books for stacking, cardboard scraps, scissors, string, straws, bouncy balls, tennis balls, dominoes, ping pong balls. This lesson provides students a chance to put their design to work and also to explain the potential problems with their machines (addressing MS-ETS1-4).*

To start, I have the students reflecting on the task of the machine. This was given to them in the previous lesson,* Rube Goldberg Machine Introduction. *They will respond to the following prompt in their student notes sheet, using one another and their previous day's notes sheet, as well.

*What is the task of your machine? What is the job it needs to accomplish?*

After 3-4 minutes, I will ask one or two students to share their responses with the class, correcting any errors or misconceptions along the way.

10 minutes

Using their original design idea from the previous lesson, students work together using the available materials (or any they brought from home) to build an initial model. This time is really for experimentation with the materials. How do they operate? Are they heavy? Are they too light? What happens when...?

Students are given ten minutes to explore the materials they've requested in any way they wish, building a knowledge base for their design and engineering plan. If students seem to be off task during this time, I approach them and ask them to explain what they've noticed about any given material. Have you observed anything about the dominoes that surprises you, etc.

10 minutes

The next ten minutes are for reflection on the exploration of the materials. Students work in their small groups and independently to answer the following questions in their notes sheets:

*From exploring the materials, what did you learn about them?*

*Are you planning on changing your design from your initial phase?*

*If so, what changes will you make?*

*What materials will you need?*

After 7-8 minutes, I ask a group to share their information, but give the expectation to everyone that they will be building off of what the group shares. * Did anyone else find that to be true? Did anyone else find something different about the dominoes, etc?*

Student work sample A is attempting to explain how they used a book and a car (in their initial design) to pop the balloon and they realized the car wasn't heavy (hale) enough to pop the balloon on their own. They then taped the push pin to the book and when the car hit the book, there was enough weight to pop the balloon.

Student work sample B is explaining that in their initial design they had a cart with only 1 weight inside to pop the balloon. After testing the materials, they realized 1 weight would not be sufficient and that they would need 3 to do the job.

15 minutes

Next, students work to create their procedure for the engineering/building process. Students must create a step-by-step plan for how they construct their machine. They also must make a detailed list of materials (what they need and how much of it they will need).

Finally, students sketch a final draft of their machine, identifying the specific materials and quantities, labeled on the diagram. To help them stay organized with their information, I provide them with the following questions on their notes sheets:

*List the materials you need in specific amounts:*

*Explain the steps to build your machine:*

*Step 1- _______________ .*

*Step 2- _______________ .*

*Step 3- _______________ .*

*Step 4- _______________ .*

*Sketch your machine on a separate sheet of paper. Be sure to label all materials. *

5 minutes

For a bit more reflection, students will respond to the following questions on their notes sheet. You can have them work independently or in small groups, starting with a short conversation, then a response to the conversation.

*What is the hardest part about designing something, a machine specifically?*

*What could make the design process easier for you and your group?*

At the end of the time, say 3 to 4 minutes, I ask one or two students to share their responses.