US Environmental Protection Agency
Epa: Measuring P H Experiment
This is an activity that deals with acid rain. "This experiment will illustrate how to measure the approximate pH of chemicals in water using a pH indicator." It is easy to follow the comprehensive set of directions.
Curated OER
Educational Technology Clearinghouse: Maps Etc: Pre Colonial Africa, 1872
A map of Africa showing the continent prior to the Berlin Conference of 1885, when the most powerful countries in Europe at the time convened to make their territorial claims on Africa and establish their colonial borders at the start of...
Curated OER
Etc: Maps Etc: Physical, Political, and Economic Asia, 1872
A map of Asia from 1872, showing physical features including mountain systems, deserts, lakes, rivers with direction of flow, coastal features, and ocean currents, political boundaries and foreign possessions at the time, and commercial...
Curated OER
Educational Technology Clearinghouse: Maps Etc: Drawing North America, 1872
A map exercise from 1872 for drawing North America. The map shows the general outline of the coasts, major waters and rivers, and a vertical profile cross-section of the continent from the San Francisco Bay area to Cape Hatteras....
Curated OER
Educational Technology Clearinghouse: Maps Etc: Rhode Island, 1872
A map from 1872 of Rhode Island, with map inserts of Providence, Newport, and Block Island. The map shows counties and county seats, principal cities, ports, and towns, railroads, terrain and coastal features, and rivers. Clock symbols...