PPT
Mr. E. Science

Characteristics of Waves

For Students 6th - 8th Standards
Waves, waves, and more waves. Here, class members look at the many types and characteristics of energy waves including transverse, longitudinal, standing, seismic, p-waves, s-waves, and l-waves. 
PPT
Curated OER

Atomic Theory

For Teachers 7th - 12th
An extremely thorough presentation walks new chemists through the basics of matter. There really isn't a unifying theme, however So many topics are covered: forces, elements, atomic structure, chemical properties, compounds, quarks,...