So, I need to create a physics demonstration that highlights a concept of introductory physics out of household items. Does anybody know of any good ones I could use?
I think this qualifies for the same rules as a homework problem. Why don't you suggest an idea for what you want to do and then we can help you refine it to something presentable.
I'm sure the real point of the assignment was to make you think about how the laws of physics are reflected in everyday phenomena. If you don't do the thinking, then you haven't really done the assignment.