Here you will find resources to help educators and their students to determine the flow of surface water using a topographic map; Examine factors that allow thunderstorms to persist for long periods of time; Explain the connection between topography and flash flooding; Realize the relationship between population growth and the likelihood of fatalities due to a flash flood; Read accounts of flash-flood disasters; Understand that wise land-used planning can reduce the danger from flash floods.

Here you will find resources to help educators and their students to use radar images to calculate the speed and direction of thunderstorm movement; examine factors that allow thunderstorms to last for long periods of time; learn how weather radar is used to track storms; understand the differences in the intensities of thunderstorms.

Here you will find resources to help educators and their students to investigate relationships between air temperature and water vapor; observe and record changes in the shape and movement of clouds; simulate cloud formation in a bottle; describe cloud formation in terms of expansional cooling; explain the conditions that cause thunderstorms to mature; learn about conditions that may lead to the development of severe weather.

Here you will find resources to help educators and their students to investigate how the density of air changes with change in air temperatures; relate the frequency of occurrence of thunderstorms to the topography of an area; relate the occurrence of thunderstorms to the temperatures in an area; recognize areas in the US where thunderstorms are relatively frequent. Learn how air masses at different temperatures interact; understand why severe weather often occurs during specific seasons.

Here you will find resources to help educators and their students to graph the annual Pacific fish catch from 1957 to 1983; using your graph, identify past El Nino events and predict future events; understand the relationship between upwelling, phytoplankton abundance, and fish catches in the equatorial Pacific, use an Earth system approach to consider how phytoplankton production is related to cycles of matter that could affect your state and community.

Here you will find resources to help educators and their students to map variations in temperature and precipitation n the US during the 1982-1983 El Nino Event; Understand that weather changes caused by this El Nino event had global consequences; determine if the variation caused by El Nino occurred in your own state; predict what effect a new El Nino event might have on your state's agriculture.

Here you will find resources to help educators and their students to understand how sea surface temperatures vary during an El Nino event understand how to use data on sea surface temperatures to make inferences about changes in ocean circulation; use remote-sensing data to determine the extent and duration of the 1997 El Nino event.

Here you will find resources to help educators and their students to understand the general paths of surface ocean currents; determine the average speed of surface ocean currents in the Pacific Ocean; understand how the winds drive surface ocean circulation; understand how surface ocean circulation patterns change during an El Nino event; understand how ocean circulation can influence climate; understand how the Coriolis effect influences ocean circulation patterns.

Here you will find resources to help educators and their students to understand how water temperature affects circulation within a body of water; understand how salinity affects circulation within a body of water; understand the meanings of ocean currents and water mass; understand the nature and causes of water circulation in the deep ocean; investigate convection cells and their relationship to deep ocean circulation.

Here you will find resources to help educators and their students to understand the effect of the wind on the movement of water at the ocean surface; understand the effect of the Coriolis force on the movement of objects or materials when they are observed in a rotating system; learn why the ocean is layered by the temperature and density; describe the meaning of pycnocline and thermocline in your own words.