This teaching box will help your students understand how conservation of energy determines the average temperature of a planet, including Earth. These activities also illustrate how the greenhouse effect prevents our home planet from becoming a frozen ball of ice!

Teaching Boxes are collections of classroom-ready and standards-aligned activities, content, and multimedia that build student understanding of science, technology, engineering, and math.

Teaching Box Group

Overview

UCAR Center for Science Education Teaching Boxes are themed collections of classroom-ready educational resources to build student understanding of science, technology, engineering, and math (STEM). Resources highlighted within teaching boxes are from various science education programs and all have been vetted by the UCAR Center for Science Education team.

• Topic: Planetary Energy Balance and the Greenhouse Effect
• Level: Middle and high school
• How to use this resource: Each tab correlates with a part of the scope and sequence for this topic and includes links to activities, background content, and multimedia resources. Select resources within each tab that are best suited for your students to meet the learning goals. (There are often more resources linked within each section than you will need.)

Using some simple physics and math, students can determine the theoretical average global temperature of a planet. When one performs this calculation for Earth, the calculated temperature is well below the freezing point of water. Clearly, there is something missing from this theory-based calculation. The missing piece is the greenhouse effect, which raises Earth's temperature to a level that supports life. This teaching box provides resources to help you and your students learn about Earth's theoretical temperature and the extra warming provided by the greenhouse effect. Here's an overview of the topics of each of the tabs in this teaching box:

Albedo tab

Bright surfaces reflect away most of the sunlight that strikes them. Dark surfaces absorb light and consequently warm up. "Albedo" is the scientific term for the lightness or darkness of a surface. An understanding of the concept of albedo is a prerequisite to performing calculations of theoretical temperature presented in the "Planetary Energy Balance" tab later in this teaching box.

Any object with a temperature above absolute zero gives off energy as electromagnetic radiation. When sunlight shines on a planet, the planet warms... and gets rid of excess heat by emitting infrared "light". The law of energy conservation tells us that the incoming sunlight and outgoing infrared must balance out. Physicists use a hypothetical object called a blackbody radiator to calculate energy balances and temperature in cases like this. The Blackbody Radiator tab explains how the Stefan-Boltzmann law allows us to calculate the temperature of objects. This section is also a prerequisite for the calculations in the "Planetary Energy Balance" tab.

Planetary Energy Balance tab

Using some simple physics and math, students can determine the theoretical average global temperature of Earth. This section also provides some computer-based simulations that "do the math" for you, if you'd rather not have your students perform the calculations themselves. The bottom line is that Earth would be very cold and rather inhospitable to most life if there was no greenhouse effect. This tab sets the stage for study of the greenhouse effect in the remaining two tabs of this teaching box.

Greenhouse Effect tab

Without the greenhouse effect, Earth would be quite cold and a rather unpleasant place to live. This tab provides several resources, including videos, that explain the greenhouse effect. It also directs you to a couple of computer-based simulations that allow your students to experiment with the greenhouse effect.

Energy Budget tab

This optional section is an extension of the concepts covered in the Greenhouse Effect tab. There are several versions of an atmospheric energy budget diagram available online. The diagram presents a more detailed look at the greenhouse effect and the path of energy through our planet's atmosphere.

Science Education Standards

NGSS Crosscutting Concepts

• Energy and matter: Flows, cycles, and conservation. Tracking fluxes of energy and matter into, out of, and within systems helps one understand the systems’ possibilities and limitations.
• Stability and change: For natural and built systems alike, conditions of stability and determinants of rates of change or evolution of a system are critical elements of study.
• Systems and system models: Defining the system under study - specifying its boundaries and making explicit a model of that system - provides tools for understanding and testing ideas that are applicable throughout science and engineering.
• Cause and effect: Mechanism and explanation. Events have causes, sometimes simple, sometimes multifaceted. A major activity of science is investigating and explaining causal relationships and the mechanisms by which they are mediated. Such mechanisms can then be tested across given contexts and used to predict and explain events in new contexts.
• Scale, proportion, and quantity. In considering phenomena, it is critical to recognize what is relevant at different measures of size, time, and energy and to recognize how changes in scale, proportion, or quantity affect a system’s structure or performance.

NGSS Practices

• Using mathematics and computational thinking
• Developing and using models
• Analyzing and interpreting data
• Constructing explanations

NGSS Disciplinary Core Ideas

• PS3.A: Definitions of Energy
• PS3.B: Conservation of Energy and Energy Transfer
• ESS2.A: Earth's Materials and Systems
• ESS2.D: Weather and Climate
• ESS3.D: Global Climate Change
• ESS3.A: Natural Resources
• ESS3.C: Human Impacts on Earth Systems