Chapter 6, page 84
Hollow-sphere conception. Children with the hollow-earth conception think that the earth is
hollow like a jack-o’-lantern or a goldfish bowl. People live on the flat part at the bottom of the earth, as
shown in Figure 6.4c. We live not on the outside of the ball, but on the inside, in the middle of the ball.
Places such as the U.S. and China are on the flat surface on the inside. According to one idea held by
these children, the edge of the earth is high in the sky! (Vosniadou & Brewer, 1992, p. 564).
Interview:
Interviewer: Would you ever reach the edge of the earth
[if you kept walking and walking]?Commentary:Child: No, you would have to be in a spaceship if
you’re going to go to the end of the earth.The edge of the earth is the point marked
“edge” in Figure 6.4d. To get to that edge,
Interviewer: Is there an edge to the earth?
Child: No. Only if you go up.one must fly far up in a spaceship.The hollow earth conception was held by 10% of first graders, 20% of third graders, and 30% of fifth
graders. Most elementary school teachers have probably never imagined that some of their students think
that we live in the inside of a sphere, that there is a kind of sky-wall at the end of the earth, or that the edge
of the earth is high up in the sky!
Flattened-sphere conception. Children with this conception thought that the earth was round
like a thick pancake. In fact, the children explicitly said it was like a pancake. These children believe that
one can walk all the way around the earth—there is no edge to the earth. However, the earth is mainly flat
on the top and the bottom. This conception was held by 5% of the first graders, 15% of the third graders,
and none of the fifth graders.
Spherical-earth conception. The final conception of the earth’s shape was the conception of the
earth as a sphere, which is the scientific conception. Children with this conception believed that the earth
was round like a ball, that people do not fall off the earth because of gravity, and that people can travel all
the way around the earth. This conception was held by 15% of first graders, 40% of third graders, and
60% of fifth graders.
Why do children develop these conceptions of the earth’s shape? We have seen that children
develop five different conceptions of the earth’s shape. The flat-earth conception is prevalent among five-
or six-year-old children and then quickly become less common. Later, children tend to develop other
conceptions such as the dual-earth conception, the flattened-sphere conception, and the hollow-earth
conception. Only at about fifth or sixth grade do a majority of children develop the spherical-earth
conception.
How do these very different ideas arise? Parents and teachers do not intentionally teach children that
the earth is flat, that there are two earths, or that the earth is hollow. Then where do these ideas come
from? Vosniadou and Brewer noted that the initial idea that many children hold—the flat-earth
conception—is consistent with two important facts about the earth that young children are familiar with:
(1) the earth looks flat and (2) things fall downward. In fact, the flat-earth conception gives a very good
explanation of these facts. According to the flat-earth conception, the earth looks flat because it is flat.
And when we drop things, those things fall downward and hit the flat earth that we are standing on.
As children grow older, they begin to encounter new ideas presented by teachers, parents, and the
media. They hear that the earth is round. They see globes and pictures of the earth taken from space. But
these ideas do not make sense to most children, given the facts they know (the earth is flat, and things fall
downward). The earth cannot be round because it looks flat and because people would fall off the bottom
half of the ball. Faced with these new ideas, children develop new alternative conceptions to make sense of
what adults are telling them.