Cells of Power!Cells of Power!

Rhonda Hawley, EducatorRhonda Hawley, EducatorDeveloped with funding from Developed with funding from

The MathScience Innovation CenterThe MathScience Innovation Center

What do leaves do for a What do leaves do for a tree?tree?

Leaves collect sunlight and use it to make food for the tree.

An Average Leaf Looks An Average Leaf Looks Like This:Like This:

But What If We . . .

Take a Look Inside a Leaf!

http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb4pg5.htm

These cells trap sunlight and convert it to chemical energy to make food for

the tree.

This is where thecells of power can be found

So the bigger the leaf . . .So the bigger the leaf . . .So the bigger the leaf . .So the bigger the leaf . .

The more sunlight that is trapped The more sunlight that is trapped = more chemical energy to make = more chemical energy to make more food . . . Right?more food . . . Right?

But wait, is size the most But wait, is size the most important thing to a leaf?important thing to a leaf? What if it’s cloudy? What if it’s cloudy? Or something blocks Or something blocks the sun? the sun?

Then, what can a leaf Then, what can a leaf do to trap sunlight?do to trap sunlight?

Position! Position! Position!Position! Position! Position!

What else can a tree or What else can a tree or plant do to make the most plant do to make the most

energy/food possible?energy/food possible? Grow lots and Grow lots and

lots of small lots of small leaves!leaves!

-or--or-

Grow a few Grow a few really big really big leaves!leaves!

Take a Look at These LeavesTake a Look at These Leaves Which one makes the Which one makes the

most energy/food?most energy/food?

Which leaf makes the Which leaf makes the least amount of least amount of energy/food?energy/food?

How can we tell?How can we tell?

SURFACE AREA!SURFACE AREA!

Count each whole box with an Count each whole box with an “X”“X”

What about the pieces of boxes?What about the pieces of boxes?

When you calculate the When you calculate the area of a leaf, you discoverarea of a leaf, you discover the potential amount of the potential amount of solar energy that a leaf solar energy that a leaf can collect.can collect.

Now, let’s compare the area of a man-made Now, let’s compare the area of a man-made solar collector . . .solar collector . . .

Solar panels!Solar panels! They trap sunlight too!They trap sunlight too!

What do they do with the sunlight What do they do with the sunlight they collect?they collect?

Do they make food with that sunlight? Do they make food with that sunlight?

What do they do with the trapped What do they do with the trapped energy?energy?

Let’s Compare the Two!Let’s Compare the Two!

Leaves trap sunlightLeaves trap sunlight and convert it to and convert it to chemical energy to chemical energy to make their food.make their food.

Solar panels collect Solar panels collect sunlight and convert sunlight and convert it to electrical energyit to electrical energy for us to use in our for us to use in our daily lives!daily lives!

The solar energy collected byThe solar energy collected by both trees and solar panels are both trees and solar panels are considered to be considered to be renewable resourcesrenewable resources because the sun’s because the sun’s energy will not be used up for many lifetimes to come.energy will not be used up for many lifetimes to come.

Take a Look Inside These Take a Look Inside These Cells of Power!Cells of Power!

Let’s Explore Those Let’s Explore Those Solar Cells of Power!Solar Cells of Power!

Don’t forget Don’t forget about:about: PositionPosition QuantityQuantity Surface AreaSurface Area

Credits:Credits: Diagram of the Leaf found at University of Winnipeg: Evolution, Diagram of the Leaf found at University of Winnipeg: Evolution,

Ecology and Biodiversity Online Lab Manual; Lab #4; Kingdom Ecology and Biodiversity Online Lab Manual; Lab #4; Kingdom Plantae; The Leaf. Plantae; The Leaf. http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/index.htm http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/index.htm

Still Photos of solar panels in slides 14 & 15 photographed by Ian Still Photos of solar panels in slides 14 & 15 photographed by Ian Britton found at www.FreeFoto.com Britton found at www.FreeFoto.com

Diagram used in slide 16, courtesy of U.S. Department of Energy; Diagram used in slide 16, courtesy of U.S. Department of Energy; further information found at: further information found at: http://encyclobeamia.solarbotics.net/articles/solar_cell.html http://encyclobeamia.solarbotics.net/articles/solar_cell.html

Still Photos of leaves taken by Rhonda Hawley and from on-line clip Still Photos of leaves taken by Rhonda Hawley and from on-line clip

art file.art file.

Video clip of Solar Cars found at http://www.discoveryeducation.com Video clip of Solar Cars found at http://www.discoveryeducation.com