Explore using units in calculations with the Leaf Area Index (LAI). LAI is a ratio that describes the number of square meters of leaves per square meter of available land surface. Because of the units in the ratio, it is dimensionless.
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Explore using units for calculations with Normalized Difference Vegetation Index (NDVI). NDVI is a ratio of different light wavelength reflectance which can be used to map the density of green vegetation.
In this lesson, students investigate and identify various phytoplankton using images that were previously taken with a compound microscope. Credit: This lesson is modified from a lesson of the same name created by The Center for Microbial Oceanography: Research and Education 
Students use Phytopia: Exploration of the Marine Ecosystem, a computer-based tool, to investigate various phytoplankton species and topics relating to phytoplankton biology.
Students will learn about and describe the different classifications of Air Quality Index and the importance of standards in air quality monitoring. Students will also use scientific evidence and reasoning to support a claim about long-term trends in air quality in the United States.
Students will review the sources of the six criteria pollutants for which the EPA has established standards for and describe their impacts on human health and the environment.
Students will analyze how air pollution may be transported over time. Students will also differentiate between sources of air pollution and describe how air pollution interacts with the Earth System.
Students will analyze and describe the relationship between air pollution and minority and poverty populations. Students will evaluate environmental problems in relation to social inequalities.