Activity 1: The Planter Challenge

1. Introduce the challenge. Tell the students they will be building a green bean planter that will mechanically drop three or more seeds onto a piece of masking tape.
2. Engage the students by reviewing the six types of simple machines. Write the names of each simple machine on the board, and invite students to give examples for each. If possible, also show an example of each simple machine.
3. Show the students the materials and ask, "How can you make a simple green bean planter from these materials?" Give the students additional design parameters and performance parameters:
   1. The seeds must be dropped by the machine.
   2. The seeds must be dropped in intervals.
   3. At least one simple machine must be employed.
   4. You may only use the materials provided to the class.
4. After discussing their ideas, distribute The Planter Challenge handout and instruct the students to complete the Brainstorm and Design section.
5. Have the students explain their initial planter design to groups of three to four students. After each individual idea is explained, have the students create a group prototype which could include selecting one design to move forward with, or combining pieces from multiple student designs and creating a new prototype. Have the students draw their proposed group design on The Planter Challenge handout.
6. Allow students 20 minutes to build and test their prototype. Remind the students to follow their group prototype design, testing periodically and redesigning as necessary. Design problems and solutions must be noted on The Planter Challenge handout in the Build, Test, Evaluate, and Redesign section. If needed, adjust time and material constraints to meet the needs of the students.
7. Evaluate student designs by having groups demonstrate their planter prototypes and determine if they meet design parameters and performance expectations.
8. Invite the students to share their designs and how they solved any problems that came up. Emphasize the key themes in this challenge—using simple machines and achieving precise results—by asking questions such as:
   • What limited your design solutions?
   • What methods did you use to move the seed precisely onto the target row?
   • What strategies were successful for planting one seed at a time?
   • How did your understanding of simple machines influence the design of your planter?
9. Instruct the students to complete the Reflection section of The Planter Challenge handout. Assess student work for completeness and accuracy.

Activity 2: The Math Challenge

1. Explain to the students that having access to a machine that plants green bean seeds is important to farmers. Additionally, there is a great amount of planning that needs to happen before the planter can enter the field.
2. Distribute The Math Challenge handout. Read the introduction together, and instruct the students to solve the problems independently.
3. Lead a class discussion about why we use machines and how long it would take students if they had to plant the seeds by hand. Have the students synthesize the information and share the importance of using machines in agricultural production.

Variation

Take the lesson outside and have the students test their planter prototypes in a garden bed. Cover the seeds with soil and apply water. Routinely care for the plants and enjoy a harvest of green beans.