A broadcast outage is impacting parts of Central Southern Colorado, including Salida and the San Luis Valley. More information here.

Stream live and on-demand content now on our new app:
RMPBS+

Help tell more stories in 2026 - make a year-end gift!

Give Now
Crash Course Physics show's poster

Geometric Optics: Crash Course Physics #38

Explore the world of physics, motion, and energy with Dr. Shini Somara.

Geometric Optics: Crash Course Physics #38

Season 1 Episode 38 | 9m 26s | CC

Sunlight, moonlight, torchlight, and flashlight... They all come from different places, but they’re the very same thing: light! It’s what makes it possible for us to see the world around us, so it’s worth a close, hard look. For instance, how does light travel? When you flip that switch in the bathroom to brush your teeth, how does light move from the light bulb, to the mirror, and into your eyes?

Related stories

Health & Wellness
‘It makes me feel seen:’ Medicaid can now cover abortions in Colorado
A Colorado Springs woman finds solace in a new state law that expands Medicaid to cover abortions, reflecting on the financial stress she faced after her own procedure.
 | Priya Shahi
Education
DU law students bring nation’s largest tribal will clinic to Ignacio
For four days, 25 students from the University of Denver Sturm College of Law helped tribal members write wills through the school’s Tribal Wills Project.
 | Ziyi Xu
Housing & Transportation
Undercovered: Colorado's home insurance dilemma
Homeowners in Colorado face difficult decisions when it comes to insuring their home. With increasing fires and more intensive hail, we look into the looming crisis - and what the state government is doing to address it.
 | Andrea Kramar

Crash Course Physics

Watch more episodes

See more
See more