Does light travel in a straight line?

Today my grade 4 class learnt all about light and that it travels in a straight line.  It was very interesting to watch them to explore with light and figure out that even though light disperses it still continues through in a straight line. They are really getting good at scientific journal writing as well.  I am one proud science teacher. Awesome!!

Oh and because Pink Floyd's Dark Side of the Moon album art is a wicked prism and reminds me of our light unit we listened to the entire album while we worked.  #RockNRollScience

The concept we learn was something like this ...