Inquiry Skills UsedThis is a technological problem-solving activity.

Safety Considerations Students should be reminded of safe scissor behaviour. Students can avoid scratching themselves while attempting to put the brad through the cardboard by using a hole punch. If using thick cardboard, hole punching the spot instead of trying to force the brad through the cardboard is highly recommended.

BackgroundAt this level, students are expected to understand a functional structure and identify the various processes and components of a system (e.g., robot, front-end loader/backhoe). The students should also be able to calculate the mechanical advantage (MA = force needed without a simple machine divided by force needed with a simple machine) of various mechanical systems (e.g., a robotic arm transfers force through the fulcrum or a simple fixed pulley system redirects the effort force). This activity will provide a concrete example of how a robotic arm functions, thus describing systems that could potentially improve theproductivity of various industries (e.g., robotic systems have increased the rate of production in factories that assemble the fine parts of wristwatches).

What You Need Strips of heavy poster paper or cardboard, at least 4 per student (nylon stocking boards are a good

thickness and length) Brads or split pins (wing clips, butterflies, or whatever you like to call them) Round tipped scissors A hole punch

What to Do1. Pre-cut cardboard in strips 2-3cm X 6-10cm. 2. Use 2 strips to make an 'X'. 3. Poke a brad through the middle of the 'X'. 4. Do that again so that you now have two hinged 'X's. 5. Use 2 brads to attach the 'tops' of the 'X's to each other. 6. Cut a triangle on the bottom side of one of the 'X's. 7. Hold on to the other ends. 8. As you squeeze and open the ends of the X, the whole thing will extend and contract. It is possible

to pick up small objects in the 'teeth' created by cutting out the triangles.

This activity is suggested for use with the Ontario Curriculum.

Grade 8: Structures and Mechanisms

Contributed by: Ellen Webb

All systems include an input and an output.

Systems are designed to accomplish tasks.

...an activity that will always be at arm’s reach

Where to Go from Here?A challenge is to make theirs the “best.” What does best mean? Changing the variables of the length and width of the strips, different types of cardboard, the number of 'X's attached together to add length, it is possible to determine the optimum conditions to lift the greatest mass from the greatest distance.

STSE LinksResearch how humans have used this technology to create work-saving devices and find ways scissoring mechanisms are being used in labour-saving mechanisms.

Cross Curricular ConnectionsLanguage

In partners or small groups, write a proposal for a device that will meet a need. Include the design plan, the materials, the projected cost, the different components of the system, strategies used to be more efficient, the outline of the user guide, and a possible advertising strategy.

Write an instruction manual for your robotic arm.

Visual Arts This activity also incorporates visual arts when producing a three-dimensional work of art that

communicates a specific idea.