READ: What is Science?

Sometimes learning about science is frustrating because scientific knowledge is always changing. But that’s also what makes science exciting. Occasionally, science moves forward in giant steps. More commonly, however, science advances in baby steps.

Giant steps in science may occur if a scientist introduces a major new idea. For example, in 1666, Isaac Newton introduced the idea that gravity is universal. People had long known that things fall to the ground because they are attracted by Earth. But Newton proposed that everything in the universe exerts a force of attraction on everything else. This idea is known as Newton’s law of universal gravitation.

Q: How do you think Newton’s law of universal gravitation might have influenced the advancement of science?

A: Newton’s law allowed scientists to understand many different phenomena. It explains not only why things always fall down toward the ground or roll downhill. It also explains the motion of many other objects. For example, it explains why planets orbit the sun. The idea of universal gravity even helped scientists discover the planets Neptune and Pluto.

Baby steps in science occur as small bits of evidence gradually accumulate. The accumulating evidence lets scientists refine and expand on earlier ideas. For example, the scientific idea of the atom was introduced in the early 1800s. But scientists came to understand the structure of the atom only as evidence accumulated over the next two centuries. Their understanding of atomic structure continues to expand today.

The advancement of science is sometimes a very bumpy road. New knowledge and ideas aren’t always accepted at first, and scientists may be mocked for their ideas. The idea that Earth’s continents drift on the planet’s surface is a good example. This idea was first proposed by a scientist named Alfred Wegener in the early 1900s. Wegener also proposed that all of the present continents had once formed one supercontinent, which he named Pangaea. You can see a sketch of Pangaea in Figure below. Other scientists not only rejected Wegener’s ideas, but ridiculed Wegener for even suggesting them. It wasn’t until the 1950s that enough evidence had accumulated for scientists to realize that Wegener had been right. Unfortunately, Wegener did not live long enough to see his ideas accepted.

Q: What types of evidence might support Wegener’s ideas?

A: Several types of evidence support Wegener’s ideas. For example, similar fossils and rock formations have been found on continents that are now separated by oceans. It is also now known that Earth’s crust consists of rigid plates that slide over molten rock below them. This explains how continents can drift. Even the shapes of today’s continents show how they once fit together, like pieces of a giant jigsaw puzzle.

CK-12 Foundation, Physical Science. http://creativecommons.org/licenses/by-nc-sa/3.0/