Dr. Troy Mensen is a family medicine doctor based in the Chicago area. He completed his undergraduate degree at the University of Northern Iowa and his doctorate at Des Moines University College of ...

Density is a fundamental concept in chemistry that describes the relationship between mass and volume of a substance. This video offers a thorough explanation of density, its significance, and how to ...

Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

Copper atoms are larger than aluminum atoms. There are fewer copper atoms than aluminum atoms in the cubes. Copper atoms are much more massive than aluminum atoms. The extra mass makes copper more ...

What is density, and how does it apply to the universe? From dogs and water to stars and galaxies, this video uses humor and ...

Osteoporosis is a bone disease that’s common in the United States, affecting almost 20 percent of women and 5 percent of men over age 50. Osteoporosis occurs when bones are weakened by hormone shifts ...