" Splash is for 9–12th graders only; Spark is for 7–8th graders only."
This sound like they are strict about the official grade level (unfortunately).
https://esp.mit.edu/learn/Splash/index.html .
Is this really so? Has anyone had a younger child attend? (Or at least inquired directly whether they would allow a younger child in some classes, particularly in Spark ?)
https://esp.mit.edu/learn/newgrades.html"We will not be able to make exceptions for academically advanced middle school students to attend high school Splash. However, we hope that middle school students will find more options available to them at Spark ..."