Designing and Scaling a Racecourse

• This exploration will introduce students to scaling and converting units by sketching and designing a Racecourse. The students will work in groups to find an area where they can lay out their course. They will then measure the area they have for the course and sketch this area with the proper dimensions in their engineering notebook. Once the students have the sketch of the actual size of the course, they will use unit conversions to scale the course down so that it fits in their engineering notebook.

• Once the course is scaled-down. They will also draw a scaled down-version of the Speedbot on their course so that they can visualize how large/small the robot is compared to their course. This will help them to decide how the robot can navigate the course. For example, are the turns wide enough? Can the robot get through easily?

• Once the group has designed their scaled-down course, they will use these dimensions to lay out their actual-sized course using tape or other materials. They will then drive their robot through the course using the Driver Program to test and ensure their measurements and calculations are correct. The students will be encouraged to test and edit the dimensions of their course as they see fit.

• There is the option to scale using graph paper instead of carrying out multiple conversions.

• These skills will help them succeed in the Robo Rally Challenge where they will be required to combine their course with another group and drive the robot through the new combined course the fastest!

Use the measurements of the robots while designing the racecourses to ensure that the robots have enough room to move and turn without crossing the lines of the course.

Allow groups to use different spaces within the classroom when possible, but the same space can be used if there is only one available. Consider allowing the same space to be used in different configurations by having groups re-tape their lanes.

Another option instead of measuring all of the scaled distances would be to use graph paper to make drawing the scaled course easier.

Using graph paper in the students' engineering notebook, ask them to create a scaled version of the area you sketched using your recorded measurements. Before starting, decide the scale at which you would like to recreate the area in meters. For example, each square on the graph paper could represent a single square meter. In the example above, a square meter is 4 boxes by 4 boxes on the graph paper.

You should consider the size of your graph paper when choosing the scale. Too large of a scale may not fit on the graph paper that you are using. Add a scaled version of the VEX V5 Speedbot to your graph paper to help visualize its scaled size in comparison to the scaled area you have created.

Start by having students convert to a standard unit of measurement either by converting the centimeter measurements of the robots to meters (in decimals) or by converting their meter measurements of the space to centimeters. Use the standard unit of measurement to more easily create the scale.

The approximate measurements of the Speedbot are 30 cm across the front and 24 cm down the side.

30 cm = 300 mm = 0.3 m
24 cm = 240 mm = 0.24 m

You can also sketch the course using graph paper:

Ask the students to sketch a racecourse within the scaled area that they made in their engineering notebook. Keep in mind the size of the VEX V5 Speedbot and how it is represented in the scale that they used. The robot should be able to navigate the course without leaving the sides of the racecourse.

Try to be as creative as possible with the course by adding multiple turns and straightaways. Use arrows or other symbols to indicate the direction the robot on the racecourse should travel in. In addition, indicate the location of the starting and finishing lines using a symbol or lines.

Have your students add a symbol or drawing for the VEX V5 Speedbot that is at scale to help them recognize whether their course's size can accommodate the robots.

Students are likely to report that the most difficult part in creating a full-sized version of the course based on the scaled version is the need for precise measurements. This experience should highlight human errors in taking measurements, especially when a measurement is only carried out once. For planning purposes, one way to reduce measurement errors is to measure more than once and average the measurements taken across those multiple attempts. This way your longest and shortest measurements, which might both be inaccurate, are adjusted to a more likely accurate value.

Give students time to:

• Test their Racecourse

• Take note of needed size/dimension changes

• Make those changes by sketching and re-scaling

• Re-test.

After the students have tested their Racecourses and made the necessary improvements, engage them in a class discussion. First have the students share their experiences with a partner or small group before asking the students to engage in a full-class discussion.

Facilitate the discussion by asking:

• What parts of the original design of your Racecourse were sized correctly? What parts needed re-sized and why?

• How did scaling your Racecourse allow you to make changes to the size easier?

• Did having the size of the scaled Speedbot drawn on the scaled version of your Racecourse help you to decide how the robot should move? Why or why not?

• If you were to do this activity over, is there anything you would have done differently?