PLANETARY ORBITS

1. Begin by practicing your coding skills! Open the Ozobot Evo app and select “Play without signing in”. Follow the on-screen instructions to pair your robot to your tablet. Then tap the “Challenges” menu in the lower left corner and open the Ozoblockly Editor.
2. Watch the Ozoblockly tutorial to get started. Then choose whether you will code as “pre-reader”, “beginner”, “intermediate”, “advanced”, or “master”. Try writing a few programs until you get comfortable with the Ozobot. Continue working on the tutorials and experimenting with your own programs until you feel comfortable with writing code.
3. Now it’s time to code one Ozobot to model Earth’s orbit around the Sun. Write your program so it takes approximately 36 seconds for this model orbit. Because the real planet Earth takes about 365 ¼ days to orbit the Sun, we can say this model is scaled at a rate of about 10 days per second.
   • Don’t worry if you don’t know how to begin! Just get your Ozobot following the Earth orbit line and use a timer to reason about your program. As you try different things in your program (like telling your robot to drive for a certain distance or adjusting the speed at which the robot travels) you will get a better sense of how to write a program so your robot can complete the orbit in 36 seconds.
4. After you have programmed your Ozobot to travel at the correct speed, program its lights blue and green to indicate that it’s representing Earth.
   • SPOILER ALERT: This video shows one of our Task Prototypers explaining her thought process in programming her Ozobot. Only watch it if you feel truly stuck and that you are unable to proceed any further. In this video she explains her thoughts about halfway through the task, before she completed all parts of the goal.
5. Once you have programmed the Earth Ozobot, turn it off and pair the second Ozobot to your tablet. Adapt your existing code to make this Ozobot orbit at the same scale. If Mars takes 687 days to orbit the Sun, and our model is scaled at a rate of 10 days per second, how long should this robot take to complete one orbit on the mat?
6. After you have programmed your second Ozobot to travel at the correct speed, program its lights a reddish orange color to indicate that it’s representing Mars.
7. Now that you have both programs on your Ozobots, test them out! Place both your Earth and Mars robots in the positions marked May 5, 2018. Start them moving and see if they both arrive at the November 26, 2018 position at the same time!
   • If the robots are having a hard time getting started, begin the Earth Ozobot a little behind its starting position and hold Mars in place. Release Mars at the same time the Earth Ozobot crosses its starting position.

Now that you’ve accomplished your goal, find out more about space careers in the Exploring Further section below.