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Supercourse: Epidemiology, the Internet, and Global Health
Supercourse is a global, continuously updated repository of lectures on public health and prevention targeting educators across the world. Supercourse has a network of over 32000 scientists in 151 countries who are sharing for free a library of over 2500 lectures. Originally funded three times by NASA, and now by the National Library of Medicine, this "Library of Lectures" has been developed from passionate scientific lectures from across the world. The result is a technology for inexpensive, su
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Soils as Sponges: How Much Water Does Soil Hold?
The purpose of this resource is to introduce students to gravemetric measurements - calculating the amount of water in a soil sample or other substance by weighting it before and after drying.
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Just Passing Through (Beginner version)
The purpose of this resource is to develop an understanding of how water flows through different soils and how it is transformed when it flows through these soils. Students time the flow of water through different soils and observe the amount of water held and also the filtering ability of the soils. They will also observe the filtering ability of soils by noting the clarity of the water before and after it passes through the soil.
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Just Passing Through
The purpose of this resource is to develop an understanding of some of the relationships between soils of different types and water. Students will time the flow of water through soils with different properties and measure the amount of water held in these soils. They will also experiment with the filtering ability of soils by testing the pH of the water before and after it passes through the soil and observing changes to the clarity of the water and to the characteristics of the soil. Students w
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Soil Particle Density Protocol
The purpose of this resource is to measure the soil particle density of each horizon in a soil profile. Students weigh a sample of dry, sieved soil from a horizon, mix it with distilled water and then boil the mixture to remove any air. The mixture cools for a day and then students add water until the volume of the mixture is 100 mL. Students measure the temperature and mass of the final mixture and use the Soil Particle Density Data Sheet to calculate the soil particle density. Three samples sh
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Optional Soil Moisture Sensor Protocol
The purpose of this resource is to measure the water content of soil based on the electrical resistance of soil moisture sensors. Students install soil moisture sensors in holes that are 10 cm, 30 cm, 60 cm, and 90 cm deep. They take daily readings of soil moisture data by connecting a meter to the sensors and using a calibration curve to determine the soil water content at each depth.
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Gravimetric Soil Moisture Protocols
The purpose of this resource is to measure soil water content by mass. Students collect soil samples with a trowel or auger and weigh them, dry them, and then weigh them again. The soil water content is determined by calculating the difference between the wet sample mass and the dry sample mass.
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Optional Soil Infiltration Protocol
The purpose of this resource is to determine the rate at which water soaks into the ground. Students place two cans into the soil and add water to them to a depth of at least 5 cm. Students measure and record the time it takes the water level to drop a fixed 2 - 4 cm distance. Students repeat the measurement to determine how easily water moves vertically through the soil.
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Water Walk
The purpose of this resource is to become familiar with the hydrology of your locale. Students will study and visit the Hydrology Study Site, conduct a visual survey to discover information about local land cover, water quality, and document their findings. They will use this initial investigation to raise questions about local land cover and/or water chemistry issues that may require further investigation.
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Water Vapor Protocol
The purpose of this activity is to measure the total precipitable water vapor (column water vapor) in the atmosphere above an observer's site. Students point a GLOBE/GIFTS water vapor instrument at the sun and record the voltage readings from a digital voltmeter. They observe sky conditions near the Sun and perform the Cloud Protocols. Intended outcomes are that students understand the concept that the atmosphere prevents some of the sun's light from reaching Earth's surface, how water vapor mea
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Water Temperature Protocol
The purpose of this resource is to measure the temperature of a water sample. Students use an alcohol-filled thermometer or meter to measure the temperature of water. The meter requires calibration before use; the accuracy of the thermometer needs to be checked before use.
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Water Transparency Protocol
The purpose of this resource is to determine the transparency of water. Students measure water transparency at their undisturbed study site using a transparency tube or Secchi disk.
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Salinity Protocol
The purpose of this resource is to measure the salinity of the water at your hydrology site. Students use a hydrometer to measure the specific gravity of the water sample, and use a thermometer to measure the temperature. With these two values, students will use tables to determine the salinity.
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Precipitation Protocols
The purpose of this activity is to determine the amount of moisture input to the local environment by measuring rain and snowfall and to measure the pH of precipitation. To do so students use a rain gauge and a snowboard to measure the daily amount of precipitation. Special pH measuring techniques for precipitation are used to determine the pH of rain and melted snow. Intended outcomes are that students will understand that precipitation is measured in depth and this depth is assumed to apply to
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pH Protocol
The purpose of this resource is to measure the pH of water. Students use either a pH meter or pH paper to measure the pH. If using the pH meter, the meter needs to be calibrated with buffer solutions that have pH values of 4, 7, and 10.
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Nitrate Protocol
The purpose of this resource is to measure the nitrate-nitrogen of water. Students will use a nitrate kit to measure the nitrate-nitrogen in the water at their hydrology site. The exact procedure depends on the instructions in the nitrate kit used.
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Salinity Titration Protocol
The purpose of this resource is to measure the salinity of the water using a salinity titration kit. Students will measure the salinity of saltwater using a salinity titration kit.
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Relative Humidity Protocol
The purpose of this activity is to measure relative humidity using both a sling psychrometer and a digital hygrometer. Intended outcomes are that students learn to quantify humidity and that there is a limit to the amount of water vapor that the air can hold. Students gain insight into why rain drops and snow flakes form and why there is precipitation. Supporting background materials for both student and teacher are included.
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Dissolved Oxygen Protocol
The purpose of this resource is to measure the amount of oxygen dissolved in water. Students use a dissolved oxygen kit or meter to measure the dissolved oxygen in the water at their hydrology site. The exact procedure depends on the instructions in the dissolved oxygen kit or meter used. The meter requires calibration before use.
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Electrical Conductivity Protocol
The purpose of this resource is to measure the conductivity of water at a freshwater hydrology site. Students calibrate and take electrical conductivity measurements using an electrical conductivity meter. Students estimate the total dissolved solids from the electrical conductivity measurements.
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