Dog Days of Summer

Challenge
The days from July 3 to August 11 are known as the Dog Days of Summer, usually the hottest, muggiest of the year. This is the period when Sirius, the Dog Star, rises at the same time as the Sun. The ancient Romans defined this period and believed the weather was warmer because Sirius was also providing heat for the Earth, hence Dog Days of Summer. So, how can this heat help us with this month’s STEM challenge? Heat rises which is going to be a good fact to know when building your solar updraft tower, which harnesses the Sun’s heat energy to do work. Our version to going to use empty cylinders with a pinwheel attached to the top. The goal is to get the pinwheel to rotate from the heat rising through the solar tower. What materials would be best to use for the tower sections? Do certain items warm up faster or more than others? How can the pinwheel be attached so it can spin freely? How high off the ground should your updraft tower be? Your challenge is to create an updraft tower that uses the Sun’s heat energy to spin the pinwheel the most amount of times. Updraft Tower Example.

Your updraft tower does have some criteria and constraints. Only the materials provided can be used in your design. The tower needs to be at least 1 foot tall. Every group should build and construct the same type of pinwheel for fair testing during the rotations.
 
*This idea and challenge can be further explored in the Advancing STEM Grade 4 Unit, Full of Potential: The Effects of Energy.

Materials

• aluminum cans (various sizes without tops and bottoms)
• can opener
• cardboard tubes (various sizes)
• plastic cylinder containers (various sizes)
• different colored duct tape
• clear tape
• paper clips (for attaching the pinwheel)
• paper for pinwheel
• simple pinwheel template

Hints and Tips for Success

1. Allow students planning and discussion time by having them experiment with the items to see how flexible, movable, and heavy they are. Students could conduct mini experiments by placing different items in the heat to see which warm up the fastest or are the warmest by the end of a set time period. Students could also experiment with different sized pinwheels and the type of paper used to make them to see which spins easiest or the best.
2. After experimenting, allow student groups to plan their design. Include as many ways to improve their updraft towers as needed.
3. For differentiation, adjust the amount of materials available and allowed to use, add any additional materials, take away certain materials, show them different versions others have created, help determine how to attach the pinwheel or how to raise the bottom so air may enter. Adjustments could be made to make it more challenging or simpler.
4. Make sure to standardize the pinwheel students are using and the area they are placing their towers. Or, the latter could be part of their experiment/challenge. Additionally, how high the towers are placed off the ground could impact how well it works. This could also be standardized.
5. Connect to science by discussing solar power/energy, renewable/non-renewable energy, convection, weather patterns, energy, work, etc.

By: Clay Nolan, CA BOCES Learning Resources