Curated OER
Subtraction Worksheet
In this subtraction skills worksheet, students solve 4 problems that require them to subtract visual number sentences by counting the pictures, writing equations, and finding the differences.
Florida-Spectrum Environmental Services
Florida Spectrum: Chemical Fact Sheet: Cobalt
A nice summary of the properties uses and some environmental information on this element.
Wikimedia
Wikipedia: Cobalt
This Wikipedia online encyclopedia site provides information on the element Cobalt (Co). Entry includes the characteristics, history, biological role, occurrence, compounds, isotopes, and more about Cobalt.
Royal Society of Chemistry
Royal Society of Chemistry: Cobalt
A short summary of basic information on cobalt, including history.
TED Talks
Ted: Ted Ed: Cobalt: Periodic Table of Videos
The team at Periodicvideos has created a TED-Ed Lesson for every element of the periodic table. This one is about cobalt. Take this lesson to learn about its role in color televisions. [1:42]
US Environmental Protection Agency
Epa: Carbon Monoxide (Co)
This page gives the sources of carbon monoxide along with health effects and recommendations for CO levels in homes.
Web Elements
Web Elements Periodic Table: Cobalt
An excellent summary of the basic data about cobalt, along its properties and how it is isolated chemically.