Insanely Fun DIY Science Experiments at Home with Physics Girl

To fellow Canadian viewers: my favorite diffraction grating is the one found on dollar bills. There is a small somewhat transparent circle in the large maple leaf, that is a diffraction grating. If you have a laser pointer (I have done it with dollar store pet laser pointers), shine it through the disk, and you will see on the wall (in a dark room, that helps) the value of the dollar bill in a circle (for example, $20). Fun for the whole family! And your pets.