Every pumpkin has a different size and circumference. The easiest way to measure the circumference of a pumpkin is with a piece of string. Each student gets a pumpkin, string, marker and ruler. The string wraps around the center of the pumpkin and a students marks where the wrapped length meets with the start of the string. Then the string is laid flat on a table and measured to get the circumference. Once complete, the class can compare different circumferences to see who has the biggest and smallest.
The ridges in a pumpkin are a help in pretty evenly segmenting it into a large pie graph. Students should count each ridge on the pumpkin and then divide 360 degrees by that answer. This will determine how many degrees each section comprises. This activity can be expanded to show different examples colored in on the pumpkin. For example, students can color 50 degrees of the pumpkin with a marker.
Volume calculations on a pumpkin are a straightforward and easy activity. The circumference calculations can be used to discover the radius by dividing the measurement by 2 * 3.14 (the value of pi). For example, if the circumference is 20 cm, input 20/ (2 * 3.14) to get 3.18 cm as the radius. To calculate the volume, use 4/3 * 3.14 * the radius measurement to the third power. Using the last example, the calculation of 4/3 * 3.14 * 3.18^3 would equal 134 cm^3 for the volume. You can extend this activity to find the surface area of the pumpkin. Use the radius measurement and calculate 4 * 3.14 * the radius to the second power. Using the last examples, the calculations would be 4 * 3.14 * 3.18^2 to equal 10.1 ^2. Students can compare and contrast different volumes and surface areas with a chart.
Students can learn geometrical shapes with different pumpkin face designs. Using protractors and rulers, students get assigned different angles and lengths for face sections that include eyes, nose, mouth and ears. Use markers to draw directly on the pumpkin and then they can be displayed around the classroom to showcase the different shapes and angles. Students can draw the degree measurements and shape names directly on the pumpkin or label them with masking tape.