- 1). Pour the liquid that you are attempting to determine the volume of into the graduated cylinder. (If you are attempting to calculate the volume of a solid object, skip ahead to Step 6.)
- 2). Bend down until you are eye level with the top of the liquid in the graduated cylinder.
- 3). Identify the meniscus. This is the curved upper portion of the liquid. The stronger the attraction is between the liquid and the walls of the graduated cylinder, the more convex the meniscus will be. The volume of a liquid will always be measured from the bottom of the meniscus.
- 4). Observe the markings on the cylinder. Determine if the bottom of the meniscus lines up perfectly with a graduation on the scale provided on the cylinder, or if it is between graduations.
- 5). Record the volume of the liquid by recording the exact number of the graduation where the bottom of the meniscus falls. Be sure to record the unit of measurement of the cylinder. This will typically be milliliters. If the meniscus falls in between two graduations, the volume of the liquid is considered as being halfway between them. If this occurs you can calculate the volume by calculating the average between the two numbers represented by the graduations. The average of the numbers can be calculated by adding the two numbers together, and then dividing that number by two. (For example: If the bottom of the meniscus falls between the graduations designating 2.0 ml and 2.1 ml, the volume would be equivalent to the average of these two numbers, 2.05 [(2.0+2.1)/2)].) You have now determined the volume of the liquid in the cylinder. If you wish to continue on to the next steps, you will learn how to calculate the volume of solid objects based on how much water they displace in the graduated cylinder.
- 6). Make sure you have the volume of liquid in the graduated cylinder recorded and written down.
- 7). Obtain a solid object that is small enough to be fully submerged in the liquid in the graduated cylinder, but which will not cause the water level to rise over the graduations on the cylinder when the object is added.
- 8). Place the object in the graduated cylinder. If it does not fully submerge, use a dissecting needle to push it down until it is fully submerged.
- 9). Record the volume of the liquid with the object fully submerged in it. This is done by recording the value designated by the graduation where the bottom of the meniscus now falls. (Refer to Step # 5 if the bottom of the meniscus falls between graduations.) Write down this number.
- 10
Subtract the volume of the liquid in the graduated cylinder from the volume of the liquid with the object submerged in it (Volume of Liquid with Object - Volume of Liquid). The result of your calculation is the volume of the solid object.
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