PIRA 2B40.60 - Density and Buoyancy: Hydrometers in Different Liquids
Photos Show the Demonstration Used by the University of Texas
at Austin.
Instructions / Notes:
- One graduated cylinder has 250 ml of normal water.
- The other (designated) graduated cylinder has 250 ml of Saline Solution.
- Hydrometers should be lowered in and allowed to settle.
- Dry hydrometers with paper towel once removed and place back into foam slits
immediately.
Concepts Conveyed:
- This demonstration shows the difference of buoyancy in the solutions displayed by the
varying resting depths of the hydrometers.
Demo Staff Notes:
- Fill cylinders prior to class (one from tap water, other from solution container).
- Provide paper towel for drying off hydrometers to the professor.
- After class dump out water in tap cylinder, pour saline solution back into container and
WASH OUT CYLINDER THAT CONTAINED SOLUTION. Dry out both if possible.
- Ensure hydrometers are DRY and safely snug in foam slits.
Instructions for making saline solution:
- Pour 1 Liter of tap water into container.
- On a scale: zero to weight of
baby
beaker (provided in box): 30.6 grams.
- Measure 50 grams of salt (80.6 grams of total weight).
- Pour salt into container.
- Stir until solution is clear.
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