Activity 1: Brainstorming the Definition of a Machine

1. Review with your students your rules for brainstorming and cooperative group activities.
2. Place your students in groups of three or four students. Give each group a set or markers and one piece of white 12"x18" construction paper. Instruct the "scribe" or "recorder" of each cooperative group to write one of the following questions on each side of the white paper. Read the questions aloud as you write them on the board:
   • What is a machine?
   • Why do people use machines?
3. Explain to the students that they will do two brainstorms. They will have three to five minutes to brainstorm and write their answers for the first question. At the signal they must stop, turn their paper over, and brainstorm answers to the second question. If necessary, adjust the time for each brainstorm. It is important to provide enough time to write down major ideas, but not quite enough time to write every detail.
4. Have the groups complete their brainstorms.
5. Allow three to five minutes for each group to review and determine two of their "best" or "most unique" answers from each brainstorming list. Have each group write their choices in complete sentences on four separate sentence strips.
6. Have each group post their answers under the appropriate brainstorm question that you have written on the board. Encourage a classroom discussion about the sentences.
7. Create a class definition for the word "machine."

Activity 2: Discovering a Machine

1. Read the book, Big Book of Big Tractors by Lisa Jane Gillespie and Mike Byrne. This book describes and illustrates many machines used in agriculture. Help students understand that various machines make the production of our food more efficient. Our food and some of the fiber used to make our clothes and other necessities come from farms. Machines used on farms make it possible for farms to produce enough food for our population. As you read the book, ask the students, "If a farmer did not have this machine, how would he/she [insert task name here]" For example, without a Seed Drill, how would a farmer plant hundreds or thousands of acres of corn or wheat? In most cases the labor would have to be performed by hand. Help students see that it would not be possible for farmers to produce enough food for our population without machines.
2. Project The Tractor picture on a large screen and lead the class in a discussion that previews the questions on the People and Machines activity sheet. Discuss that scientists call machines either "simple" or "complex." The tractor is a complex machine made of simple machines such as wheels, axles, and levers.
3. Group students into pairs. Give each pair of students a pencil, a picture of a machine, and one copy of the People and Machines activity sheet. Instruct students to use their pictures to answer the questions on the activity sheet. You may choose to give teams pictures of soil preparation equipment, planters, cultivators, harvesters, etc. Allow sufficient time to complete the activity. Have each pair share their answers with the class. Discuss the variety of equipment farmers use.

Activity 3: Similarities and Differences of Machines

1. For this activity sheet, each pair of students will need a pencil, two pictures of machines, and a Venn Diagram activity sheet. If you have not previously performed a Venn diagram activity with your students, take time to do one as a whole class before proceeding.
2. Instruct the students to write the name of one machine on the line in one of the circles and the name of the other machine on the line in the other circle. In each circle, they should list the characteristics that are unique to each particular machine. Where the circles intersect, the students should list ways in which the machines are similar.
3. Have students volunteer to share their results, and/or create a bulletin board to display the Venn diagrams.

Activity 4: Machines at My House

1. Distribute one or both of the Machines at My House activity sheets and explain the homework assignment(s) to your students. Have the students complete the assignment(s) at home.
2. After collecting the homework, discuss what it would be like if certain machines were not available to assist people in the kitchen.

 Variations

• Using a picture of a machine and a variety of materials, have students invent an improved machine.
• Do the Venn diagram as a whole class activity.
• Have students write a description of how to build or plant something. Their explanations must include a description of the machines used in the process.