Use bench to investigate images in lenses
http://www.physicsclassroom.com/Physics-Interactives/Refraction-and-Lenses/Optics-Bench
Use bench to investigate images in lenses
http://www.physicsclassroom.com/Physics-Interactives/Refraction-and-Lenses/Optics-Bench
Investigate effect of angle, media
http://www.physicsclassroom.com/Physics-Interactives/Refraction-and-Lenses/Refraction
See effect of filters
http://www.physicsclassroom.com/Physics-Interactives/Light-and-Color/Color-Filters
add vectors and see resultant
https://phet.colorado.edu/sims/html/vector-addition/latest/vector-addition_en.html
Find resultant forces in 1D
http://www.thephysicsaviary.com/Physics/Programs/Games/NetForceSimpleGame/index.html
Helen rates this resource as good
Component or tip to tail for adding vectors
http://www.physicsclassroom.com/Physics-Interactives/Vectors-and-Projectiles/Vector-Addition
Add different colours, explore uploaded image
http://www.physicsclassroom.com/Physics-Interactives/Light-and-Color/RGB-Color-Addition
Change uniform colors and see effect
http://www.physicsclassroom.com/Physics-Interactives/Light-and-Color/Painting-with-CMY