I begin the lesson by introducing a new vocabulary word with which students will need to become familiar. I introduce the term hydroelectricity by writing it on the board in the front of the room. I ask students to split the word into parts and to idenitfy any parts of the word that are familiar to them. Since we completed a study of electrical circuits earlier in the year, my students are able to pick out and idenitfy the root word electricity. I then ask students if they are familiar with the prefix hydro- or if they have heard this word part in other contexts. I define the word part as a prefix that means water. I then define hydroelectricity as electrical power generated by water.
The topic of hydroelectricity and turbines can seem daunting, but there are a variety of resources that can help every teacher understand the basics of how hydropower is created. This teacher research overview can help you learn more about how hydropower is created prior to teaching the lesson.
Because this topic is complex, I provide my students with multiple means to access learning about hydropower. I begin by showing them this graphic which demonstrates how hydropower is generated. This computer animation is engaging to children and introduces the process of hydropower generation in a step-by-step format. After students have viewed the graphic, I provide each student with a copy of this worksheet. The worksheet uses a similar graphic and provides students with the opportunity to name and write about each step in the power generating process. Finally, I ask students to read the article The Power of Water in the power company research packet. This article provides a bit more detail on how electrical current is generated and does a good job of explaining the energy transformation from mechanical to electrical energy. These multiple methods for explaining the same topic give students multiple entry points into a complex subject and help students build lasting understanding.
After students have built an understanding of how electricity is produced in a hydroelectric dam, I ask students to consider why people might use hydroelectric power instead of another source of power. I want my students to begin to explore the pros and cons of hydroelectriciy as a power source. I provide time for students to discuss the topic with their science partners and to share their thinking with the whole class. This discussion serves as a good entry point into the broader topic of how meeting human wants and needs can have a detrimental environmental impact.
A video of my students sharing their thinking can be found here.