Grade Level: 5–8
Using the painting, Cakes by artist Wayne Thiebaud, students will learn and practice math concepts of volume and surface area. Then they will create a bold cake painting, either online or with classroom art materials.
American, born 1920
oil on canvas, 152.4 x 182.9 cm (60 x 72 in.)
National Gallery of Art, Gift in Honor of the 50th Anniversary of the National Gallery of Art from the Collectors Committee, the 50th Anniversary Gift Committee, and The Circle, with Additional Support from the Abrams Family in Memory of Harry N. Abrams
Have you ever seen a scene like this? What seems unusual about it? (Note the thin, delicate stands—almost like a circus performer balancing plates on a straw!)
Wayne Thiebaud, c. 1985–1986
©Wayne Thiebaud/Licensed by VAGA, New York, NY
American, born 1920
Eight Lipsticks, 1988
drypoint on Somerset Satin paper, 17.8 x 15.2 cm (7 x 6 in.)
National Gallery of Art, Gift of Kathan Brown
8. Thiebaud painted things other than food. He made still lifes of neckties, eyeglasses, lipsticks, even cows and dogs. He also painted large portraits of human figures, applying thick paint in bright colors against stark white backgrounds.
9. Thiebaud went on to paint cityscapes—from the steep hills of San Francisco to the colorful landscapes of the Sacramento Valley in California.
10. Wayne Thiebaud retired from full-time teaching in 1990. He lives in Northern California and continues to paint.
Begin by looking carefully at the painting Cakes by Wayne Thiebaud with your students. Display a copy of the painting and ask students:
Read the facts “Ten Things About Thiebaud” at the very beginning of the lesson and ask students what they learned about the artist that might help explain his painting.
Most of the cakes shown are the same geometric solid, a cylinder. Solid shapes such as cylinders have volume. In this case, the volume is the amount of cake inside.
Let's focus on the Valentine cake:
The baker sells it as a 10-inch cake. Which part of the cake measures 10 inches? (diameter)
To calculate the volume of this cake, use this formula: V = pi(r2)(h)
What measures do you need for this formula? (radius and height)
Since the diameter of the cake is 10", the radius (r) equals 5". The height of the cake (h) is 4.5". You can use 3.14 as an approximation for pi and calculate the volume of cake using V = pi(r2)(h).
Answer = 353.25 cubic inches
Now, how can we calculate the amount of frosting on the cake?
First, try to estimate the amount of frosting you think it will take to ice the cake. Here are your choices: 12 square inches, 50 square inches, 98 square inches, or 222 square inches. This is how to figure the answer:
The formula for the surface area of a cylinder is: 2(pi)(r2) + 2(pi)(r)(h), but the formula for the cake is: pi(r2) + 2(pi)(r)(h)
Why are they different? The cake is a cylinder, but the bottom is not frosted; so you only need to include the surface area of the top; so you don't need to double pi(r2).
Use what you know about the cake to calculate the surface area.
Answer: 222 square inches of frosting
Doesn't that sound like a lot of frosting for one cake? If you have ever frosted a cake, you know it takes only a cup or two of frosting to cover its surface. It is amazing that those cups contain frosting to cover several hundred square inches!
Use what you have learned to calculate the volume and surface area of this 8" cake. It is 4" high.
V = pi(r2)(h)
SA = pi(r2) + 2(pi)(r)(h)
Now that students are familiar with the painting, have them make their own boldly-designed cakes paintings. What type of cake do they like? What shape is their cake? round? rectangular? another shape? What colors are used for this type of cake? How would they decorate it?
Have students challenge their classmates with other math problems relating to the cakes in this painting. What about the ones that have already been cut into? How much cake and icing would a slice contain?