The Arduino is an open-source electronics prototyping platform containing hardware and software that can be used for interactive objects or monitoring different things such as motors, sensors, etc. It uses the Arduino programming language which is a set of C/C++ programming functions that can be called from your code.
You can make a copy of the notes and activities to help you start learning about the Arduino and C++ code.
Beginner Arduino Projects
Watch Stem Launch student, Jacob Johnson's exploration of LEDs: