Cut open the top of a pumpkin and let the children get their hands dirty and gooey for this sensory activity recommended by PreschoolRock.com. Ask the students to describe what they feel as their hands touch the "pumpkin guts." Scoop out the pumpkin guts and set the insides on a tray for further exploration with sight and smell. Use the pumpkin seeds for later counting or baking activities.
Create a book to demonstrate a pumpkin's life cycle from a tiny white seed planted in the brown ground to a green vine that grows green leaves, then yellow flowers, sprouts a green pumpkin that grows bigger until it's an orange pumpkin ready to pick. Print pages for children to color or precut the shapes for children to paste into their books. Play a video or a computer animation to show the process from seed to pumpkin.
Preschoolers put their thinking skills to the test on this science activity from EverythingPreschool.com. Ask your class if it thinks a pumpkin will float or sink in a tub of water. Students put a pumpkin sticker on top of a picture of water if they think the pumpkin will float or at the bottom of the water if they think the pumpkin will sink. Chart the students' responses on a bar graph or pie chart to show the number of guesses for sink and float. Perform the experiment to discover the answer. Compare a hollowed-out pumpkin and solid pumpkin for a more in-depth activity.
Plant pumpkins for a real-life example of a pumpkin's life cycle. Use milk cartons with the tops cut off for planters. Fill each carton with moist potting soil and plant the seed. Have the students draw what they see in journals. Below the drawings, write down the number of days elapsed and the part of the cycle (seed, vine, leaf, flower or pumpkin). After the pumpkins sprout, send the plants home with the students.