Misconception: Students get confused reconciling the coordinate system with the point Scratch uses as the center for Sprites.
Explain nested for loops using a car odometer, the innermost loop controlling the ones digit must cycle fully before the outer loops steps forward, to help students better understand nested loops through a real world example.
Misconception: The update in the index in a for loop (i.e., the third part of the for loop control statement) happens after the all the steps inside of the loop have happened.
Emphasize to students that in CSS id is typically more specific than class, as beginners often struggle to disambiguate these attributes.
Misconception: Students get confused by the multiple equals signs comparison operators in Javascript making it difficult to motivate the difference to beginning students.
Misconception: If you consistently use the same variable names during class in lectures and examples, students may incorrectly assume objects in Java can only have those names.
Misconception: students struggle with the onMousePress method (and other mouse interaction methods) in the Java objectdraw Library from Williams College; they need help understanding it’s called even when don’t explicitly call it.
Teach "if" statements before "switch" statements, then explain how "switch" is a specialized case of "if" by translating an "if" statement into a "switch" statement.