This video segment from IdahoPTV's D4K explains and gives examples of the 4 states of matter: solid, liquid, gas, and plasma.

Thinking about the coefficients of static and kinetic friction. Created by Sal Khan.

Students will statistically analyze data gathered in reference to the Abraham Lincoln penny.

In this activity, students are assigned a geologic profile based on a set of rock samples and are asked to arrange the samples from oldest to youngest. They then identify each rock type and record their observations of what processes might have formed it, what type of sediment it is made of, what sort of environment it might have formed in, and what agents of erosion or deposition might have been at work. Using this information, they will write a story explaining the geologic history represented by their profile and describe in detail how it might have formed.

In this activity, students use elevation and distance data to construct graphic profiles and determine the average gradients for three streams. A series of discussion questions addresses concepts of deposition, erosion, and nickpoints, and gives students practice compiling evidence to provide scientific explanations. Graphs can be constructed by hand on paper or generated using graphing software.

In this activity, students simulate deformational effects on Earth's crust using peanut butter and jelly sandwiches. These common sandwich components are used to model geologic features such as synclines, anticlines, and monoclines, and to demonstrate the effects of stresses and strains.

What happens when sugar and salt are added to water? Pour in sugar, shake in salt, and evaporate water to see the effects on concentration and conductivity. Zoom in to see how different sugar and salt compounds dissolve. Zoom in again to explore the role of water.

In this activity, learners use a chemical reaction to visualize where moisture forms on the body. Learners use the Minor's iodine-starch test, a diagnostic test that doctors use to detect hyperhidrosis (excessive sweating), to identify where moisture is forming. Learners also use this method to test the effectiveness of different antiperspirants.

This interactive activity produced for Teachers' Domain shows the relationship between tectonic boundaries and the locations of earthquake events and volcanoes around the world.

This investigation uses the relationship between volume and temperature to reinforce the ideal gas law. It also uses the data collected to find absolute zero.

Watch the ZOOM cast discover which insulator -- newspaper or aluminum foil -- is better at keeping an ice cube frozen longer.

In this video segment adapted from ZOOM, cast members show you how to make your very own electroscope. You can use it to find out if an object is electrically charged.

Intuition of how gases generate pressure in a container and why pressure x volume is proportional to the combined kinetic energy of the molecules in the volume. Created by Sal Khan.

To begin, Sal solves a constant temperature problem using PV=PV. Then he relates temperature to kinetic energy of a gas. In the second half of the video, he derives the ideal gas law. Created by Sal Khan.

Sal makes the case for the Kelvin scale of temperature and absolute zero by showing that temperature is proportional to kinetic energy. Then he explains that you need to use the Kelvin scale in the ideal gas law. To finish he does a sample ideal gas law problem. Created by Sal Khan.

Sal explains the concept of a mole. Then he derives the molar version of the ideal gas law PV=nRT, where the gas constant R=831 J/molK. Created by Sal Khan.

Sal uses the molar version of the ideal gas law to solve for the number of moles in a gas. He also shows how to convert this answer into number of molecules using Avogadro's number. Created by Sal Khan.