1. Teacher Guide
This lesson is designed to teach kids to ask a critical thinking question that you can’t just put into a search box to solve. To do that, we encourage them with smaller questions that search can help them answer. Make sure that you read the notes for each slide: they not only give you teaching tips but also provide answers and hints so you can help the kids if they are having trouble.
Remember, you can always send feedback to the Bing in the Classroom team at You can learn more about the program at bing.com/classroom and follow the daily lessons on our Partners In Learning site.
Want to extend today’s lesson? Consider using Skype in the Classroom to arrange for your class to chat with another class in today’s location. And if you are using Windows 8, you can also use the Bing apps to learn more about this location and topic; the Travel and News apps in particular make great teaching tools.
Nell Bang-Jensen is a teacher and theater artist living in Philadelphia, PA. Her passion for arts education has led her to a variety of roles including developing curriculum for Philadelphia Young Playwrights and teaching at numerous theaters and schools around the city. She works with playwrights from ages four to ninety on developing new work and is especially interested in alternative literacies and theater for social change. A graduate of Swarthmore College, she currently works in the Artistic Department of the Wilma Theater and, in addition to teaching, is a freelance actor and dramaturg. In 2011, Nell was named a Thomas J. Watson Fellow and spent her fellowship year traveling to seven countries studying how people get their names.
This lesson is designed to teach the Common Core State Standard: Measurement & Data
CCSS.Math.Content.3.MD.C.5 Recognize area as an attribute of plane figures and understand concepts of area measurement.
CCSS.Math.Content.3.MD.C.5.a A square with side length 1 unit, called "a unit square," is said to have "one square unit" of area, and can be used to measure area.
CCSS.Math.Content.3.MD.C.5.b A plane figure which can be covered without gaps or overlaps by n unit squares is said to have an area of n square units.
CCSS.Math.Content.3.MD.C.6 Measure areas by counting unit squares (square cm, square m, square in, square ft, and improvised units).
CCSS.Math.Content.3.MD.C.7.a Find the area of a rectangle with whole-number side lengths by tiling it, and show that the area is the same as would be found by multiplying the side lengths.

2. How would you find the surface area of Lake Magadi?
© Bobby Haas/Getty Images
Having this up as kids come in is a great settle down activity. You can start class by asking them for thoughts about the picture or about ideas on how they could solve the question of the day.

3. How would you find the surface area of Lake Magadi?
Kenya’s Lake Magadi is the southernmost lake in the Kenyan Rift Valley. Magadi’s alkaline water contains high concentrations of sodium carbonate brine, which often covers more than half the lake during the dry season. Flamingos and other wading birds make a home along the edges of Lake Magadi, crowding into the shallows of the lake. Colonies of flamingos can number in the thousands. Here, a few dozen appear to be taking off from Magadi’s salt waters.
Depending on time, you can either have students read this silently to themselves, have one of them read out loud, or read it out loud yourself.

4. How would you find the surface area of Lake Magadi?1
Map Search
Find Lake Magadi on a map. How would you describe its shape? 2
Web Search
How do you define surface area? How is surface area different from area? What does a “square unit” mean? 3
Image Search
Find an image that helps you visualize how to find the surface area of a square using square units. Why would it be hard to use this strategy for a circle? 4
Besides counting square units, what is the shortcut way of finding the surface area of squares and rectangles using multiplication? Why wouldn’t this work for circles? 5
What information would you need to have in order to find the surface area of a sphere or cylinder? What do these terms mean?
There are a couple of ways to use this slide, depending on how much technology you have in your classroom. You can have students find answers on their own, divide them into teams to have them do all the questions competitively, or have each team find the answer to a different question and then come back together. If you’re doing teams, it is often wise to assign them roles (one person typing, one person who is in charge of sharing back the answer, etc.)

5. How would you find the surface area of Lake Magadi?5
Minutes
You can adjust this based on how much time you want to give kids. If a group isn’t able to answer in 5 minutes, you can give them the opportunity to update at the end of class or extend time.

6. How would you find the surface area of Lake Magadi?1
Map Search
Find Lake Magadi on a map. How would you describe its shape? 2
Web Search
How do you define surface area? How is surface area different from area? What does a “square unit” mean? 3
Image Search
Find an image that helps you visualize how to find the surface area of a square using square units. Why would it be hard to use this strategy for a circle? 4
Besides counting square units, what is the shortcut way of finding the surface area of squares and rectangles using multiplication? Why wouldn’t this work for circles? 5
What information would you need to have in order to find the surface area of a sphere or cylinder? What do these terms mean?
You can ask the students verbally or let one of them come up and insert the answer or show how they got it. This way, you also have a record that you can keep as a class and share with parents, others.

7. How would you find the surface area of Lake Magadi?1
Map Search
Find Lake Magadi on a map. How would you describe its shape?
(Possible queries: “Bing/Maps: Lake Magadi”, “Bing/Images: map of Lake Magadi”).
Example found here:
Students may describe its shape as ovular or may break the lake down into other shapes that are found within it (for example, a sideways rectangle with some rounded edges, or small cylinders stacked on top of each other). They should feel free to think creatively about how they would describe it.

8. How would you find the surface area of Lake Magadi?2
Web Search
How do you define surface area? How is surface area different from area? What does a “square unit” mean?
(Possible queries: “what is surface area?”, “define: surface area”, “understanding surface area”, “what is a square unit?”).
From
Surface area is the area of a given surface. Roughly speaking, it is the "amount" of a surface (i.e., it is proportional to the amount of paint needed to cover it), and has units of distance squared. Surface area is commonly denoted for a surface in three dimensions, or for a region of the plane (in which case it is simply called "the" area.
And
Square units have four equal sides, the same as any other square. The length of those sides is equal to one unit of length. For example, 1 square inch has a side of an inch and a square centimeter has a side of a centimeter.

9. How would you find the surface area of Lake Magadi?3
Image Search
Find an image that helps you visualize how to find the surface area of a square using square units. Why would it be hard to use this strategy for a circle?
(Possible queries: “surface area of squares for kids”, “finding the surface area of a square”, “understanding surface area for kids”).
From
Students should look at an image like the one on this website to visualize how square units added together make up the surface area of this square. They should then visualize what it would look like if they were to put a circle over it (or cut out a circle from the square). Why would this make it harder to count square units? Students should recognize that the circular lines would cut many of these squares into pieces and these square units would become fractions instead of wholes.

10. How would you find the surface area of Lake Magadi?4
Web Search
Besides counting square units, what is the shortcut way of finding the surface area of squares and rectangles using multiplication? Why wouldn’t this work for circles?
(Possible queries: “for kids, how to find surface area”, “how to find surface area of a square”, “how to find surface area of a rectangle”).
From
The surface area is the total exposed area inside a given boundary. We write area in units squared. Here is an example of surface area using a square:
(See: From
This square is 4 units long on each side. The surface area is the number of square units that fit into the square. As shown in the picture, the surface area of this square is 16 total square units. With a rectangle and square we can also get the surface area by multiplying width (W) x length (L). Let's try that and see if we get the same answer: Area = W x L Area = 4 x 4 Area = 16 Note: if the units were feet for this problem, the answer would be 16 feet squared. Not just 16 feet. When we give the answer for surface area we used squared to indicate that it's a surface area and not just a straight line.
Students should recognize that this formula would not work for circles because circles don’t have a width and a length. Other measurements would have to be used.

11. How would you find the surface area of Lake Magadi?5
Web Search
What information would you need to have in order to find the surface area of a sphere or cylinder? What do these terms mean?
(Possible queries: “for kids, finding surface area of sphere”, “for kids, how to find surface area of cylinder”
From
What is a sphere?: A sphere is a three dimensional version of a circle, like a basketball or a marble. The definition of a sphere is "every point that is the same distance from a single point called the center." In order to calculate the surface area and volume of a sphere we first need to understand a few terms: Radius - The radius of a sphere is the distance from the center to the surface. It will be the same distance for a sphere no matter where it is measured on the surface.
Diameter - The diameter is a straight line from one part of the surface of the sphere to another that goes through the center of the sphere. The diameter is always twice the distance of the radius. Pi - Pi is a special number used with circles and spheres. It goes on forever, but we will use an abbreviated version where Pi = We also use the symbol π to refer to the number pi in formulas.
Surface Area of a Sphere: To find the surface area of a sphere we use a special formula. The answer to this formula will be in square units. Surface Area = 4πr2
This is the same as saying: 4 x 3.14 x radius x radius
Example problem: What is the surface area of a sphere that has a radius of 5 inches? 4πr2 = 4 x 3.14 x 5 inches x 5 inches = 314 inches2
Information for a cylinder can be found from the same website, on this page:

12. How would you find the surface area of Lake Magadi?
This slide is a chance to summarize the information from the previous slides to build your final answer to the question. It is not important that students look up the information required to solve for the exact surface area of the lake, but should instead consider how they would go about this. It may help to refer to the map of Lake Magadi and conclude what various surface area formulas could be used to find the answer. They may speculate, for example, that they could make part of the lake into a rectangle, multiply width and length to find the surface area of that, and then break down the smaller parts into different shapes, and, using the appropriate formulas, find those surface areas and add it all together. The question serves as an opportunity for students to conceptualize three-dimensional shapes and surface area, as well as gain an understanding of square units.