Beginning next with the 2017-2018 school year, all districts in Arkansas will offer a “coding block” to students in grades 7 or 8. Per the standards, this course must run a minimum of 5 weeks and include text-based coding and problem solving.
There’s sufficient scaffolding in the activity that teachers with minimal experience should easily be able to support students completing the exercise. There is nothing to install, either. As it runs completely in the browser, it should run just fine on Chromebooks.
I felt their coverage of conditionals was a tad disconnected from the activity, so would encourage you to teach it with this modification: Have students create a final product that draws short names with squares and long names with bubbles.