During our study of the sun and Earth, we delved into the fascinating concept that Earth’s rotation on its axis is responsible for the cycle of day and night. While understanding this phenomenon through books and discussions was valuable, we enhanced our comprehension by engaging in a hands-on activity: creating our very own sundials.
Participants will develop a concrete understanding of Earth’s rotation and how it influences the apparent movement of the sun across the sky. Additionally, they will gain insights into timekeeping and the concept of day and night.
- Gathering Materials: To embark on this activity, we gathered the following materials:
- A paper plate
- A pen (or any straight object)
- A compass for orientation
- Creating the Sundial: We fashioned a mountain-like structure using playdough in the center of the paper plate. Then, we inserted the pen into the playdough to make it stand upright, resembling a sundial’s gnomon.
- Orienting North: To ensure accuracy, we marked an ‘N’ for ‘north’ on the edge of the paper plate. When taking the plates outdoors, we used a compass to align the ‘N’ with the actual north direction.
- Initial Observation: We made our first observation at 9 am in the morning. Placing the plates in a sunny area, we allowed the pen to cast a shadow on the plate.
- Recording Shadows: Using a pencil, my kids drew a line from the center of the plate to the edge, marking where the shadow fell. They labeled this line with a ‘9’ to denote 9 am.
- Hourly Observations: We continued to check our plates every hour throughout the day to record our observations. By our third observation at 11 am, the kids started noticing a pattern. They realized that the distance between the first and second shadows was equal to the distance between the second and third shadows.
- Predictions: I encouraged them to mark a spot on the plates where they thought the next shadow would fall in an hour. It was a delightful moment when they discovered that their predictions were accurate.
- Continued Observations: We maintained hourly measurements for most of the day, except for one hour when we were briefly away. We adjusted the plate’s position a couple of times to ensure it remained in the sun, benefiting from the ‘N’ marking for consistent orientation.
- Discussion: From our initial observation to the last, we noticed that the shadows had covered nearly half of the plate. This prompted a discussion about the Earth’s rotation and why we experience darkness for half of a 24-hour day, as we are turned away from the sun during that time.
Through this activity, participants not only gained a practical understanding of Earth’s rotation but also explored the fundamental concept of timekeeping and the Earth-sun relationship, making science come to life in an engaging and memorable way.