Clink on a link to view Holt videos illustrating the following concepts:

Chapter 1

Hypothesis     Control and Variable    Scientific Method 

Chapter 2

Volume          Mass vs. Weight        Scientific Notation        SI 

Models 2        Latitude/Longitude     Map Information            Models 

True North      Cardinal Directions     Remote Sensing        GPS   

Elevation        Contour 1                 Contour Lines           Contour Interval and Relief

Chapter 3

Ocean            Atmosphere              Biosphere

Heat              Temp. & Heat           Solid, Liquid, Gas

Rock Cycle      Water Cycle             Carbon Cycle             Nitrogen Cycle