Straight line graphs: space invaders

Students practice calculating the parameters of y=mx+b linear equations, by blasting space-invading aliens. They can control how easy or difficult to make the task. In its easiest form, the slope and y-intercept of the alien's line are both shown onscreen, and the alien moves slowly. Students can choose to hide some or all of the line info, so that they need to figure it out for themselves. They are rewarded for doing that by scoring more points per hit. Similarly, they can make the alien move faster, if they want to. However, they can also rack up points by staying in the easiest setting, if there's where they feel comfortable at first. Students can compete against each other (class-wide hi-score) and also against themselves (personal hi-score). In its current form, this activity does not work well on the small screen of a phone, as it's hard to get the text-entry box and the graph-window to both show up on a phone screen at the same time. However, it works fine on a laptop, and should also be fine on an iPad. A big thank you to John Rowe, who made a static space invaders that was the inspiration for this version. That's here: https://teacher.desmos.com/activitybuilder/custom/5c8c8f21f74c280c599085a0 Thanks also to Desmos CL forum posters Daniel_Grubbs and pirsquared, for very helpful solutions to problems I ran into while trying to make this. Thanks!

By Raj Raizada