Question
#12 Take a photo of the science equipment on your desk. Ms Eagle will demonstrate how to use a digital scale and the method of water displacement. Explain the process of water displacement used to determine the volume of irregularly shaped objects (no flat surfaces). Determine the mass, volume and density of the brass weight.

Answer
There are a few mathematical equations you have learned in the past to determine the volume of objects with flat surfaces. For example, length x height x width determines the volume of rectangles. area of base x height works for prisms. Water displacement is the process in which you use water displaced by a submerged object to determine volume. We use this method with objects that do not have regular shapes with flat surfaces. The metric system has a convenient conversion factor in which one milliliter of liquid water displaced is equal to one cubic centimeter of solid volume. If you can determine how many milliliters of liquid water are displaced by a submerged object you can directly convert those units to volume in cubic centimeters of the solid object. The easiest way to do this is to use a graduated cylinder. Place a quantity of water in a graduated cylinder that will allow the solid object to be completely submersed. Read the meniscus on the graduated cylinder to determine starting volume. Lower the object into the water and note the final volume in the graduated cylinder. The difference in milliliters between the starting and final volume of water will be equal to the volume of the solid in cubic centimeters (cm3 or cc) You can also use an overflow container like the one you saw in class today and catch the amount of water that overflows when you place and object in the filled container.

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