If you're a no-budget filmmaker, chances are that having enough space in which to shoot is a very real issue. And cramped spaces are pretty difficult to navigate when deciding how to light your scenes, especially if you've got limited but very powerful light sources. This is why it's so important to learn the fundamental cinematography technique of bounce lighting. DP Matthew Workman of Cinematography Database gives a great lesson on how to bounce light, explaining not only how to do it, but key ideas that are important to understanding it as a concept.
Surely most filmmakers, even brand new ones, are at least somewhat aware of what it means to bounce light, but what they may not be aware of is how a spotlight can be turned into an area light by simply bouncing it off of a surface, effectively turning the surface itself into an area light that emits light across an 180-degree radius.
It's a crucial lesson on what happens when light from one source is affected by a modifier, be it a softbox, reflector, or bounce cards (or wall). So, while Workman's demonstration of how light behaves when it's bounced off of a surface is relatively basic (though extremely important), it's his explanation of this concept that may prove to be the most helpful to new filmmakers.
Source: Cinematography Database