Where Does Energy Come From?

Read page D-78

Activity 68Title: Photovoltaic Cells

Problem: How can you use solar cells to produce the most energy possible?

Hypothesis: If _____________, then ____________________________.

Background Information: Solar photovoltaic cells

• A solar photovoltaic cell absorbs light energy from the Sun (or other sources) and transforms it directly into electricity.

• Light is composed of photons, or “packets” of energy. When photons strike a solar cell, they may be reflected, absorbed, or transmitted through.

• Photovoltaic is made of two root words– photo, meaning light– voltaic, meaning related to voltage

http://www.brainpop.com/technology/energytechnology/solarenergy/

The largest photovoltaic solar power plant in the United States is becoming a reality at Nellis Air Force Base

Roof with photovoltaic cells

Procedure Part A: Making a One-cell Circuit

1. With your group, set up a circuit that uses the photovoltaic cell to run the motor, as shown in the diagram below.

Use the questions on page D-79 to help you design your investigation. Discuss a procedure with your group (4-5 people) and how you might gather your data. Answer the questions on the bottom of your template.

•The procedure should change only one variable at a time•Measurements should be taken consistently•Minimize human error

Hint: look at your equipment

Today’s Challenge:• Find the best angle to the sun to produce the

most energy.• Start with the cell flat on the ground and

increase the angle in 10° increments.• Answer the analysis questions as you work.

Analysis Questions:1. For the solar single-cell setup that made the motor spin the

fastest:– Sketch and describe the setup, including the position of the

solar cell relative to the Sun.– Explain why you think this setup worked the best.

2. For the two-cell setup:– Sketch and describe the setup.– Compare and explain the effect of having two solar cells in

series to having one.3. In most of the United States, why don’t solar cells provide

enough electricity to run a house through a full day or a full year? Use evidence from this investigation to explain.

Answer the analysis questions on the back of your template. Read the questions first and gather any information you need to answer them.

Homework:• Make a list with explanations of advantages and

disadvantages of photovoltaic cells (5 to 6 of each)• Fold a sheet of notebook paper in half• Title it, “Photovoltaic Cells: Advantages &

Disadvantages”

Photovoltaic Cells: Advantages & Disadvantages

Advantages Disadvantages