Anticipatory Set: Talk with students about carving pumpkins. Ask them about the seeds in the pumpkin. Have they ever wondered how many seeds are inside?
1-Divide students into groups of three or four. Any more than this is really too much.
2-Give each group a pumpkin that already has its lid cut off (but is still sitting on top). Each group also needs a sheet that has the following on it: a place for each group member to write their name an estimation, a place for the final total of seeds to be written, and a series of questions for the students to answer in their group. These questions could be: who's estimate was closest/farthest from the correct answer, how many more seeds were there in the pumpkin than each persons estimate, if you estimated the seeds in another pumpkin of the same size do you think your estimate would be closer or further away-explain your answer, etc.
3-Have each group of students make their estimates and then begin to count their seeds. Explain that it may be easier to count the seeds if they are placed in groups of ten or twenty.
4-After all of the seeds have been counted ask the groups to clean up. It would be a good idea to save the seeds and bake them as a reward for the students if they do a good job of following directions.
5-Allow time for each group to finish answering the questions. Then share the answers and observations with the class.
Follow-Up: Keep estimating things and then discussing the results. Bring in the baked pumpkin seeds for the students to enjoy the next day.