DENSITY
Volume
Volume is the amount of space that an object takes up. When the object is regular, such as a cube or cylinder, a ruler is the tool used to calculate volume. However, sometimes the object has an irregular shape, and to find the volume, the water displacement method is used with graduated cylinders.
Volume of a Regular Object
Volume of an Irregular Object
To read more about how to used a graduated cylinder and practice reading them, click on the graduated cylinder below.
A regular object is one in which its sides are uniform and measurable. When calculating the volume of a regular object, there are various formulas you can use. For example, the volume of a rectangular prism is its length x width x height or V = L x W x H.
To make sure you know how to properly measure with a metric ruler, click on the ruler below to watch a video.
To make sure you know how to properly calculate volume of a regular object, click on the cube above and watch the video.
An irregular object does not have uniform sides. Rulers cannot measure the sides of an irregular object, so a different method must be used. This method is called the water displacement method and it uses a tool that very accurately measures liquid, a graduated cylinder.
For example, if you needed to find the volume of a rock, you could use the water displacement method.
Procedure:
1. Pour water into a graduated cylinder.
2. Record the amount of water within the graduated cylinder by reading the meniscus at eye level.
3. Gently place rock into graduated cylinder.
4. Record the new level of water within the graduated cylinder by reading the meniscus at eye level.
5. Subtract the initial measurement (without rock) from the final measurement (with rock) to find the volume of the rock. Vfinal - Vinitial = Vrock
Graduated Cylinders
Graduated cylinders can accurately measure fluids only if read accurately. To do this, you must know about the meniscus. When water is poured into a cylinder, the top of the water column is not level. The water actually curves at the edges due to surface tension. To measure the level of the water accurately, you must do two things; 1) you must measure at the meniscus, which is the lowest level of the curve, and 2) you must adjust your eye level to the meniscus when reading the water level