Why doesn't [thing] work in [browser]?

Because there are too many standards, too many updates, etc. In general:

For Flash things, use Chrome.

For Java things, use Firefox or Safari.

Examples:

Accelerated Reader, Accelerated Math, Wordly Wise, BrainPop = Flash things, use Chrome

PowerTeacher Gradebook, Geogebra = Java things, use Firefox or Safari

- If it doesn't work in one browser, try it in another.

- If it doesn't work in any of them, run updates (OS as well as browser-specific) and reboot.

- If you're still stuck, contact your school's tech department.