EXPERIMENT 1

                             Archimede's Principle

Demonstration of Archimede's Principle -- the buoyant force on objects in a fluid

1.Setup the force sensor in Channel A.

1.      Position the force sensor above the clear plastic container. Adjust the height so the hook on the bottom of the force sensor is located just above the top of the container.

2.   Press the tare button on the sensor to zero the force.

3.   Hang the cylindrical aluminum rod from the hook on the bottom of the force sensor.

4.   Fill the pitcher with water. This will be used to add water to the container.

5.   In the sampling options window, click Keyboard to set up data acquisition from the keyboard. Name the quantity to be entered from the keyboard to be "Depth" and define the units to be "cm". This quantity will be the depth of the rod submersed in the water.

6.   Open the Calculator window. Name a function "Fluid weight" with short name "Wf" and units "N" to calculate the weight of fluid displaced by the rod. Define it to be the Depth (in cm) multiplied by the cross-sectional area of the 1" diameter rod (5.07cm²), the mass density of water (1000 kg/m³), and the acceleration of gravity g (9.8 m/s²). Divide by 10⁶ to put the result in N.

7.   Name a second function "Object weight" with short name "W" and units "N" to be the measured weight of the object. This is just (-1) multiplied by the measured Force (channel A) -- the force sensor reads downward forces as negative.

8.   Open a table with columns for Depth (keyboard), Fluid weight (calculated), and Object weight (calculated).

Predictions: How do you predict that the weight of the aluminum rod measured by the force probe will vary as a function of the weight of the fluid displaced by the rod. Be as specific as possible.