Khan Academy
Cosmic Background Radiation, Scale of the Universe, Cosmology and Astronomy
An informative video explains the density of particles immediately after the Big Bang, as well as the concept that whenever a particle was released, it would merge with another particle. Sal develops the concept of being able to receive...
Khan Academy
Cosmological Time Scale 2, Scale of the Universe, Cosmology and Astronomy
Sal compares the distance of significant objects and the timeline of events in the universe on a scaled timeline across the screen.
Khan Academy
Red Shift, Scale of the Universe, Cosmology and Astronomy
The Red Shift concept can be one of the most confusing in physics. Learners may find it helpful to start with learning more about the Doppler Effect before introducing this video.