Instruction Manual 012-12254A ® *012-12254* PASCO Earth Science Density Circulation Model ME-6816 Pouring Spout 1 Liter Reservoir Top Valve Milliliter Scale 1 Liter Reservoir Valve Handles Centimeter Scale Bottom Valve 800-772-8700 www.pasco.
Density Circulation Model ME-6816 Recommended Equipment* Other Items PASPORT Temperature Sensor (PS-2125 or equivalent) Water PASPORT Salinity Sensor (PS-2195) Ice cubes PASPORT® Interface Salt, reagent grade (non-iodized) PASCO Data Acquisition Software Food coloring (or equivalent) *See the PASCO catalog or PASCO web site at www.pasco.com for more information. Introduction The Density Circulation Model consists of two one-liter reservoirs connected by two valves.
ME-6816 012-12254A Theory Theory • Water density is affected by temperature and salinity, resulting in deep water currents in the ocean. Procedure Temperature Differences Prepare the water You will need a hot plate, two containers (one-liter or larger), water, ice cubes, a stirring rod, and food coloring. • Fill one of the containers with one liter of cool water and add six ice cubes. Stir the water until all of the ice melts.
Density Circulation Model 2. Connect the PASCO sensors to the PASCO interface. 3. Prepare the Density Circulation Model. ME-6816 Experiment Setup • Use the data acquisition software to set up a Table into which you can enter data and a Graph to view your data. 1. Use the PASCO data acquisition software to set up an experiment with a Table display of Temperature and Depth (cm). 2. Set up the experiment for manual sampling so that temperature is measured by the sensor and depth is entered manually.
ME-6816 012-12254A Data Data Warm reservoir Cool reservoir Initial Temperature Data Analysis 1. Examine the data in the Graph display. Resize the graph area if necessary to see all of the data. 2. Identify the zone of rapid temperature change on the Graph. 3. Use the data analysis tools to determine the final temperatures in both reservoirs. Questions 1. How does the colored “mixed” zone compare to the zone of rapid temperature change? 2.
Density Circulation Model ME-6816 3. Record the value of the initial conductivity of the warm reservoir in the Data section. 4. Move the salinity sensor to the cool reservoir and repeat the process to measure and record the initial conductivity of the cool reservoir. 5. Delete the two data runs after you have recorded the initial conductivity of each reservoir in the Data section. 6. Open the top valve and the bottom valve to allow circulation. Wait a few minutes. 7.
ME-6816 012-12254A Other Density Circulation Phenomena Other Density Circulation Phenomena Inversion • Put warm salt water in one reservoir and cold fresh water in the other reservoir to observe the phenomenon of temperature inversion. In an estuary, cold fresh water will sometimes “float” on top of warm salt water. Convection • Fill both reservoirs with the same temperature or same salinity of water. Add a few drops of food coloring.
