A super nice member!
I teach: West Denver Prep
To ages: 11 to 14
Some simulations are higher quality than others, but overall PhET simulations are a fantastic way for students to explore scientific concepts. These can be used in an open-ended, exploratory way (Play around with the "skateboard simulation" and tell me what you learned) or in a more focused, teacher-directed way.
One small caveat, some simulations don't work well on netbooks with low-resolution screens (1024 x 600).
Easy to use as a teacher. Videos are short and relatively shallow, but engaging and useful at conveying basic vocabulary.