To understand the impact tools (and machines) have on human society both historically and presently. Specifically, to understand how tools make our lives easier.
According to Benchmarks, this grade level is "a good time to examine how people accomplish various tasks and how machines improve on what people can perceive and do." (Benchmarks for Science Literacy, p. 129.)
The goal of this lesson is not for students to learn what the simple machines are, even though this is an underlying theme. Students will approach the lesson in a much more open fashion. They will discuss tools and how they function. This will naturally lead to acknowledgment of how tools make our lives easier.
By categorizing everyday items, students will come to understand the natural functions of tools. This base of knowledge will lead into exercises and discussions about how complex machines are a conglomerate of simpler tools and motions, as well as how tools have changed and become more sophisticated throughout history.
At the end of the lesson to reemphasize the importance of tools in human society, students will write a paper in which they imagine a world without a particular tool.
Set up stations around the classroom, as described below. Each station will challenge students to perform a task that they will not be able to do without a tool.
For this demonstration, you will need a thick piece of wood and a large nail. The nail should be hammered most of the way into the wood. You may want to have several such pieces of wood if you have a large class. Challenge students to try to pull the nail out of the wood.
For this demonstration, you will need several different unopened cans. Challenge students to try to open the cans just using their hands or to suggest ways to open them just using their own bodies.
For this demonstration, you will need several walnuts. Ask students to crack them open with their hands or to suggest ways to crack them open just using their own bodies. (Don't let students put the walnuts in their mouths.)
After the students have attempted the challenges, ask these questions:
- What do you think these three situations have in common?
- Is there something that can make it easier for us to pull out the nail, open the can, or crack open the walnut?
Bring out the hammer, the can opener, and the nutcracker. Ask for student volunteers to come up and perform the challenges using the tools.
Then, ask these questions:
- How did these tools help us perform the tasks?
- Can you think of some other examples of things you couldn't do without tools?
- Can you think of even better tools than the ones we have in class to do these tasks? (Students might suggest using an electric can opener or a power tool to take out the nail.)
- What do you think life would be like without tools? (This is a rather open ended question and is something students will think out at the end of the lesson.)
Tools in General
Step 1: Lead your students to understand how tools function, as well as how they make our lives easier.
Divide students into groups of four or five. Assign each group a few common items, some of which are direct tools, and some which are assisted by tools. Item ideas have been provided on the Tools teacher sheet. Using the index cards, have each group make a card for each assigned item.
Cards should include:
- A picture of the item (either drawn, computer generated, or cut out from a magazine)
- Two explanations-one will describe how the item functions and the other, how it makes our lives easier
Step 2: Lead your students to understand the natural functions of simple machines without using unfamiliar terminology.
After the cards are made, collect all of the cards and as a class categorize their functions. Though you may want to lead students to categorize the cards into the simple machine categories as are stated on the teacher sheet, remember that they are probably not familiar with this terminology. This categorization could be confining for students' thought processes. Let them decide the categories.
For instance, instead of wheel and axle, students may categorize items into "things that roll on wheels" or "things that use wheels to move faster than walking." Instead of ramp, they may call these items "hills" or "slants." Encourage them to find what some items have in common in order to categorize them.
Step 3: Lead students to understand that complex machines and tools are made up of the basic parts that perform basic functions.
Continue the discussion. Take the wheel barrel card. This is an item that could have been categorized in either the wheel and axle, or the lever. Ask students to try to describe the wheel barrel without one of these simple functions. It would serve a purpose, but not its full purpose.
Now students should use their Tools student esheet to briefly visit the Simple Machines page on the Canada Science and Technology Museum website. (You can also print out this page and give it to students.) Have them write down what motions or tools help make up these machines on their Tools student sheet.
This resource introduces students to the six classes of simple machines: lever, screw, ramp, wedge, wheel and axle, and pulley. Show them how these terms parallel their categorizations.
Demonstrating that tools have "evolved" over time will also help students understand how simple machines build more complex machines. Have students use their student esheet to explore websites in which they uncover some of the rich history of tools. Some examples are listed below.
You could have students explore these websites on their own, or you could have students work in groups to explore them:
Students should jot down two or three tools they found in these historical contexts on their student sheet. Then, ask them to describe how these tools are used today, or how they have changed into tools we use today. Share the individual observations with the entire class.
To assess the ideas in the benchmark, assign a two-page report. Students can select one of the following options:
"A World Without (????)"
Students fill in the name of a tool and describe how life would be without that object.
"The Invention of (????)"
Students choose an invention and describe where it came from and how the invention is a combination of simple motions as well as how it makes our lives easier. Also, what life was like before the invention. Students can explore the Inventor Archive website to find inventors and their inventions.
Regardless of the students' approach, they should cover the following in their papers:
- Explain situations in which this tool or machine makes a task easier.
- If applicable, are there things we could not sense or do at all without your machine?
- Name some things that your machine helps humans do better. (These may be once or twice removed. For instance, if the student chooses a bike, he or she may ponder how a bike helps us get around better, or take better care of our bodies through exercise.)
- What do you think life would be like without tools and machines?
Note: Consider developing a rubric for assessment of the report. There are several resources on the Internet that describe the use of rubrics in the K-12 classroom, a few of which are highlighted here.
To learn more about rubrics in general, see Make Room for Rubrics on the Scholastic site.
For specific examples of rubrics, more information, and links to other resources, check out the following sites:
Finally, you can go to Teacher Rubric Makers on the Teachnology website to create your own rubrics. At this site you can fill out forms to create rubrics suitable for your particular students, and then print them instantly from your computer.
The Magic Schoolbus site has a complete lesson on simple machines: Dirtmeister's Science Reporters Investigate and Report on Simple Machines.
For a fun, interactive game on simple machines, students can try out Simple Machines, from the Museum of Science and Industry, Chicago.