Size and scale can be difficult concepts to teach. TI staff educator Lori Lambertson talks us through one of her favorite activities, using one of her favorite dolls-Barbie.

Students really struggle with the metric system. TI staff educator Lori Lambertson tells us how she helps students get a handle on what the units really mean.

Teaching isn't just work, it's a lot of fun. Staff physicist Thomas Humphrey quickly figured out that he didn't have the answer to every question in the classroom-and that's the fun of it.

TI staff biologist Karen Kalumuck describes how she tries not to answer every question that's asked during a class. Instead, she guides her students to discover ideas for themselves.

A veteran teacher describes her first year of teaching-in Guatamala. She faced many, many challenges, but she stuck it out and has been teaching for 20 years.

What is indigo anyway? Staff physicist Paul Doherty tells the story behind ROYGBIV, and how he'd like to change that standard palette.

What coin would just barely cover the full moon? You may be surprised. TI director (and recovering astrophysicist) Linda Shore explains how our brains distort the actual size of the moon.

Take a little sound quiz with our host, Stephanie Chasteen, and learn something about how our brains locate sounds.

Have you ever really listened to a ball bounce? Exploratorium staff physicist Thomas Humphrey describes the elegant mathematics of a bouncing ball.

Despite my better judgment, I invite TI staff educator Eric Muller to do one more set of activities�several things you can do with soda straws.