Before determining volume, students must first find the area of the object. You must determine the area, as it part of the calculation to find the volume of a cylinder or prism. Multiply the object's area by the object's height to determine volume.
Methods for finding area are dependent on the object’s shape. For rectangular prisms, multiply the length of object’s base by the height of the object. For square prisms, multiply the length of one of the sides times itself. The area of a triangular prism is found by multiplying one half of the triangle’s base by the height. Cylinders, which are circular objects, have a radius. The radius starts at the middle of the circle and extends to the edge. To determine the area of a cylinder, multiply the length of the radius by 3.14, also known as pi.
Create a fun, interactive activity for students to find the volume of prisms and cylinders using centimeter-sized cubes. Find the volume of real-life prisms, such as fish tanks or boxes, by filling inside of the object with cubes. The number of cubes that will fit within the prism will determine its volume.
For a faster way to complete this activity, have students fill the bottom of the prism, without stacking cubes on top of one another. Count the number of cubes on the bottom. Start stacking one row of cubes, height-wise. Multiply the number of cubes it takes to reach the top by the total number of cubes in the bottom to determine the volume of the prism. Pour water into cylinders using a measuring cup or graduated cylinder to determine volume.
Once students have a grasp of the math behind finding the volume of prisms and cylinders, they will enjoy activities like estimating games. Ask students to find the area of a few prisms and cylinders to practice their skills. Later, show students a group of similar-sized prisms and cylinders and ask them to estimate the area and volume. Learning how to estimate has real-world applications. Once students make their predictions, have them go forward with the calculations. Ask students to compare their findings with their predictions.
Create a chart for students to fill in as they complete their calculations. A chart will help students stay organized and memorize the mathematical steps needed to calculate volume. Create one column on the chart for students to fill in the height of the prism or cylinder. Create a second column for students to calculate the area. If finding area is new to students, create a key at the bottom of the chart, which shows students the calculation for each shape. In the last column, create a space for students to calculate and record volume. Charts and worksheets help students practice and reinforce their skills.