This interactive activity speeds up the process of incubation by allowing you to go through all the days at one sitting. If your students care for their eggs – by turning them every day, and by monitoring the incubator humidity – they will be rewarded at the end with a video of a chick hatching.



Birds lay eggs in a variety of sizes. This activity gives students experience with the relative sizes and volumes of the eggs.

(a) Begin by giving groups of students a large hard-boiled chicken egg and a tape measure. Ask them to measure the approximate length and width (distance across the egg when looking down at it) of their eggs. Compare the answers in the class and discuss what we would expect as a "typical" size of a chicken egg. Then ask students to create an egg model using Play-Doh or modeling clay that is about the same size and shape as the chicken eggs. Place the model eggs on a scale to find their approximate weight. This weight, which is based on its volume, will serve as a baseline for comparing the volumes of several other bird eggs.

(b) The table contains the average lengths and widths of five bird eggs:

Bird Name



Canada Goose















In groups, have the students create clay or Play-Doh models of each of the bird eggs. Students should account for the general egg shape and its measurements when constructing the models. Point out that some eggs are very spherical, while others are more "pointy"; however, this activity is intended merely to approximate the size and shape of several eggs.

Have students make predictions about the volume of the eggs. For example, they might try to guess how the volume of a Canada goose egg compares to that of a robin egg or how many times greater the volume of a turtledove egg is than that of a hummingbird egg. They can also compare the volume of a chicken egg to the volume of the eggs of other birds. The weight of each model is proportional to its volume (e.g., an egg's clay model that weighs twice as much as another requires twice as much material, so it has twice the volume). Students should weigh each of the models and compare the weights to determine the relationships between volumes, checking their predictions.

(c) Students can conduct additional experiments. For example, the ostrich lays an egg that is 15 to 21 cm long and 10 to 15 cm wide. How many hummingbird eggs could fit inside an ostrich egg? Use a scatterplot to find out if a relationship exists between the lengths and widths of bird eggs. Students can also find the volumes of chicken eggs by measuring the volume of water that the egg displaces. Another method is to pierce the ends of a raw egg with a pin and "blow out" the contents. Either measure the contents blown out, or cover one hole with tape and refill the egg with water, whose volume can then be measured.

Teacher Notes

Typical chicken eggs, classified "large" in the grocery store, will measure about 5.7 cm long and 4.4 cm wide.

(b) Each group might construct several of each kind of clay "egg" and then distribute them among the groups so that every team does not have to make all six models.

(c) The volume of an ostrich egg can be estimated by thinking of it as a sphere with a diameter of 15 cm. In this example, V = (7.5)3 = 1770 cm³. The diameter of a hummingbird egg is 1 cm, so its volume would be estimated as V = (0.5)3 = 0.524 cm³. Therefore, the volume of the ostrich egg is nearly 3400 times that of the hummingbird! The points in the scatterplot are roughly linear, so there is a relationship between the lengths and widths of eggs of birds of different species.

This activity was modified from National Council of Teacher's of Mathematics


To look at live egg development in your class, the following, links you to a unit developed by teachers at R. K. Rutheford School. It includes introductions for building your own incubator.

  Hunters & Hunted
  What's for Lunch?
  How's the Water
  Beaks are Tools
  Backyard Birdfeeder
  Shapes & Sizes
  Lift Off
  A Big Enough Wing
  Migration Hopscotch
  Sing Out Loud
Virtual Incubator
  Dance of Love
  On the Egg
  Becoming a Bird
  The Big Deal: The Feather
  Dead or Alive
  Are Birds Dinosaurs?

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