Chemistry and Physics PLC Workshop

1. Connect Sphero. The Sphero robot is controlled and programmed using an app from your tablet or phone via Bluetooth. The Media Library has 12 Kindle Fire tablets available to borrow with the Sphero SPRK+ Power Kit.

• Open the SpheroEDU app. 
• Hold Sphero near your device. You should get a message "SPRK Connected" and Sphero's light should change to the color set on the color wheel.

2. Get to know Sphero! One of the things that makes Sphero robots so unique is that its heading is relative to the user, not relative to the robot. This makes it much easier to get Sphero robots moving in the direction you want. Note in the diagram below that zero degrees is directly away from the user while 180 degress is toward the user.

3. Aiming Sphero. When you set Sphero's direction to 0 degrees this is called "aiming" Sphero. It's important to get this right so that Sphero will follow the path and not bump into anything. To do this you need to adjust the blue "tail light" so that it is pointing directly at you. This way when Sphero rolls it will roll away from you.

• Sphero isn't the brightest crayon in the box! He must be aimed each time he starts.

4. Preparing to Drive.  

• In the Sphero EDU app click on the Drive button on the bar on the bottom of the app as shown below.

• Click on the Aim button as shown below.

• Move the blue circle around the outside of the circle to aim your Sphero. Your Sphero should be rotating around as you do this. Remember this is his "tail light", when it is pointing directly at you Sphero will move away from you forward. 

• Once you have the blue tail light aimed. Lift your finger from the circle. You will now be taken back to the Drive screen. From here you can drag the blue circle inside the gray circle to drive your Sphero robot. The blue circle on the vertical line controls the speed. Sphero can travel up to 4.5 mph! You can also change Sphero's color by dragging the little white circle to a different color in the circle of colors.

 5. Practice Aiming and Driving. 

• Change your Sphero's color to make it easier to keep track of which one is yours.
• Put your Sphero on the floor and practice aiming and driving Sphero in a straight line.

Determine Acceleration-Force-Mass Relationship

Sphero wants to have a bonfire and is going to need to find a way to haul firewood home.  Sphero needs your help to design a trailer that he can pull and load with KEVA planks! He wants to be able to take home as many planks as possible without exceeding the speed limit which is 200 cm/s. 

1. Using Zometool design a trailer that attaches to and is able to be pulled by Sphero. There are no design rules other than it must be able to carry KEVA planks and keep them on the trailer while moving.

2. After you have designed and tested your trailer you will need to write a program that rolls Sphero. Set his heading at 0, his speed at 100, and his duration to 3 seconds. Test your program, make sure you have an open space that allows Sphero to travel without a collision for the entire 3 seconds. Be sure to include Exit Program block so that Sphero stops right after traveling 3 seconds.

3.  Once Sphero is successfully rolling for 3 seconds, you will need to start collecting data so that you can tell Sphero how many KEVA planks he will be able to carry at once. 

4.  For the first run you will not carry any KEVA planks. Remember to Aim Sphero before you Start your program.

5. Record your data. In the upper right corner of the program window click on the three vertical dots. Click Sensor Data. As your program runs Sphero uses his 3 axes to collect data about his journey. We are interested in his Velocity which is measured in cm/s and his Distance which is measured in cm. Record the maximum Velocity Sphero reached during his journey. Record the total distance in cm he traveled. You may need to click on the graph to enlarge it and then double-click a couple of times to increase it to get the most accurate number possible.

6. Next, you will place one KEVA plank in your trailer and run your program again. Once again record the Velocity and Distance. 

7. Add another plank and repeat.

8. Keep adding planks until Sphero isn't able to pull his trailer.

9. What can you determine from your data?

10. What can you change to increase the number of planks Sphero can haul using your trailer?

11. Test your prediction. What happened? What can you conclude about the Acceleration-Force-Mass relationship?