Solar Connections Presented by the MathScience Innovation Center Written by Theresa Meade

What is energy? Energy is the ability to do work.

Renewable or nonrenewable? Nonrenewable energy resources get used up and cannot be remade or re-grown. Examples of nonrenewable resources include coal, oil, and petroleum products. Renewable energy resources can be remade naturally over time. Examples of renewable energy resources include wind, water, and solar energy.

Our focus is... solar energy!

What is a solar cell? A solar cell is a way to capture the sun’s energy and change it to electricity. Solar cells are also known as photovoltaic cells or PV cells.

How solar cells work…

How are PV panels built? Cells are connected to form modules and modules are connected to form arrays.

Creating a solar panel Here’s a photo of another array.

What if you wanted to add solar panels to your house? Area is all of the space inside a two dimensional figure. Perimeter is the distance around the outside of a two dimensional figure. You would need to know about area and perimeter.

Today’s focus is area… I want to buy just the right number of cells to cover my roof.

How many panels would you need? C A B What strategies could we use to find the number of PV cells in this module?

Let’s practice together! Use any of the base ten blocks as a model for the solar panels. Cover the roof with blocks and then we’ll talk about the number of panels I need for this roof. Did you only use unit blocks? How many did it take? 143

Let’s practice together! What if you used tens rods also? Do you get a different answer? Well, add the tens. 130 Then add the ones. 13 Is this the same as just using ones? Is it easier to add together?

Let’s practice together! Let’s look at our roof again. If we use all of our base ten blocks to make a model, it might be easier to find the area for our solar array. So what did we find out? How can we use these numbers to find the area of our solar array? = 143 What was the length and width of my original roof?

One more together… When you do this one, think about the quickest and easiest way to fill in the roof. Can you tell the length and width of my actual roof by using the model? Yes! The real roof is 15 meters long and 12 meters wide. Let’s add these together to find the area of our solar array How many total square meters of panels do we need for our solar array?

Independent practice I will give you a data sheet. Please work with your partner to find the area of as both roofs. Don’t worry if you don’t finish! Remember to think like a mathematician: Use the largest blocks possible, be accurate, and help your partner.

Wrap Up Let’s review some answers. How does finding area relate to column multiplication? Remember that we said a solar array 31 X 14 means adding Our answer was 434.

12 31 x _ 434 Our area method: 3 31 x

Wrap Up So what about the vertical and horizontal tens rods? What do they represent?

What if you are interested in more than just a roof? Solar power is just plain fun!

Thank you!

How many panels would you need? We could count each panel.

How many panels would you need? We could add repeatedly.

How many panels would you need? We could multiply.