Big Ideas in Earth Science

Don Duggan-Haas, PRI

Sarah R. Miller, Deposit High School


“If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generations of creatures, what statement would contain the most information in the fewest words?” (Feynman, 1963)

What is a Big Idea?

A big idea is not simply a topic that typically appears in textbooks, but a key concept that cuts across all topics within a discipline. “A big idea can be described two ways: as involving an enduring principle that transcends its origins, subject matter or place in time; and as a linchpin idea – one crucial to a student’s ability to understand a subject” (Wiggins & McTighe, 1998 p. 113). Furthermore, big ideas require uncoverage – a sustained inquiry with breadth and depth. A novice and an expert may both understand a big idea, but they likely understand it in different ways and to different degrees. A defining set of big ideas can be identified that encompasses all that is important to understand within a particular discipline. For any field, the set of ideas should be manageable – five or six or seven – so that it provides focus and cohesion.

Why seek out Big Ideas?

We are in pursuit of Big Ideas because they provide a framework for inquiry-based science, are essential for understanding, are enduring and cut across the Earth Science curriculum which encompasses geology, meteorology, oceanography and astronomy.

How are Big Ideas uncovered?

Big Ideas should fulfill the following criteria.

- Does the idea cut across the Earth science curriculum?
- Is it an idea that students will hold onto?
- Is the idea essential to understanding a variety of topics?
- Is the idea one that requires uncoverage?
- Is the entire Earth Science curriculum represented by these ideas?

An example of a Big Idea

“I believe it is the atomic hypothesis (or the atomic fact, or whatever you wish to call it) that all things are made of atoms—little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied” (Feynman, 1963).

What are Big Ideas for Earth Science? 

The Earth is a System of Systems.

The Earth System is composed of and part of a multitude of systems, which cycle and interact resulting in dynamic equilibrium (though the system evolves). The Earth is also nested in larger systems including the solar system and the universe.  However there is an inherent unpredictability in systems, which are composed of an (effectively) infinite number of interacting parts that follow simple rules. Each system is qualitatively different from, but not necessarily greater than the sum of its parts.

The Flow of Energy Drives the Cycling of Matter

The Earth is an open system. The constant flow of solar radiation powers much of Earth's ocean and atmospheric processes on the surface of the system, flow of heat from inside the Earth from radioactivity drives plate tectonics. Energy flows and cycles through the Earth system. Matter cycles within it. Cycling is largely driven by the interaction of the differential distribution of solar radiation and internal heat, and gravity. Convection drives weather and climate, ocean currents, the rock cycle and plate tectonics.

Life, Including Human Life, Influences and is Influenced by the Environment.

Photosynthetic bacteria released free oxygen into the early oceans and atmosphere, making Earth habitable for later animals.  Humans have changed the lay of the land, altered the distribution of flora and fauna and are changing atmospheric chemistry in ways that alter the climate.  Earth system processes affect where and how humans live. For example, many people live in the shadow of volcanoes because of the fertile farmland found there, however they must keep a constant vigil to maintain their safety. The human impact on the environment is growing as population increases and the use of technology expands. 

Physical and chemical principles are unchanging and drive both gradual and rapid changes in the Earth system.

Earth processes (erosion, evolution or plate tectonics, for example) operating today are the same as those operating since they arose in Earth history and they are obedient to the laws of chemistry and physics.  While the processes constantly changing the Earth are essentially fixed, their rates are not. Tipping points are reached that can result in rapid changes cascading through Earth systems. 

To Understand (Deep) Time and the Scale of Space, Models and Maps are Necessary.

The use of models is fundamental to all of the Earth Sciences. Maps and models aid in the understanding of aspects of the Earth system for which direct observation is not possible. Models assist in the comprehension of time and space at both immense and sub-microscopic scales.  When compared to the size and age of the universe, humanity is a speck in space and a blip in time.