Greenhouse Effect: Does the Physical Characteristics of Surface Materials Affect Climate?
What You Need to Know
The atmosphere is the layer of air surrounding Earth. Air is a mixture of gases in Earth's atmosphere. Weather is atmospheric conditions over a short time, such as air temperature and humidity. Climate is the average weather in a region over a long period of time. Energy is the ability to cause something to move or change. Radiation is a type of energy that travels in waves, without physical substance. Solar energy is radiation energy from the Sun. The Sun emits different types of radiation, such as visible radiation (the light you can see) and infrared radiation (heat energy you can't see). The greenhouse effect is the heating that occurs when gases in the atmosphere allow sunlight to pass through to Earth's surface but trap infrared radiation leaving from Earth's surface.
How Does the Greenhouse Effect Work?
Earth's atmosphere acts as an insulator. This means it is like a blanket that helps keep Earth's heat from escaping into space. This blanket of air allows sunlight to pass through to Earth. Some of the sunlight that hits Earth's surface is reflected back into space. The sunlight that is absorbed by surface materials causes the materials to increase in temperature. The warm surface gives off heat in the form of infrared radiation. Gases in the atmosphere absorb this heat. In turn, the heated gas particles also give off infrared radiation, some of which is sent back to Earth. This back-and-forth heat transfer is called the greenhouse effect, and the gases that absorb the heat, mainly carbon dioxide and water vapor, are called greenhouse gases.
What Does This Have to Do with Surface Characteristics Affecting Earth's Climate?
The greenhouse effect is responsible for the temperature of Earth and of the lower atmosphere. The amount of heating and cooling is influenced by different factors, but the physical characteristics of Earth's surface are the most important. This is because how the surface absorbs, reflects, and radiates radiation determines how much heat is produced. For example, sunlight falling on a white, slick glacier surface is strongly reflected back into space, resulting in minimal heating of the surface and the lower atmosphere. On the other hand, sunlight falling on dark, rough desert soil is strongly absorbed and results in significant heating of the surface and the lower atmosphere.
In a desert, where there is very little water vapor in the atmosphere, the nighttime temperature can be as much as 80° F (26° C) lower than daytime temperatures. Without the protection of the atmosphere, some places on Earth would be about 176° F (80° C) during the day and –220° F (–140° C) at night.
Real-Life Science Challenge
Life on Earth could not survive without the greenhouse effect. But is the increased production of greenhouse gases from the burning of fossil fuels causing global warming? Some say it is, but others say it isn't. The problem is that records of the weather have not been thoroughly kept for a long enough period of time to determine if there really is global warming, which would be a permanent warming change in the climate of every region on Earth. More time is needed to determine if a period of increasing warm weather is permanent or temporary.
Now, start experimenting with how the physical characteristics of surface materials affect climate.
- Glass, much like greenhouse gases, allows sunlight to pass through but traps infrared radiation.
- Design an experiment to test the effects of surface materials with different physical characteristics, such as colored soils, dry and wet soils, grass, green or dry leaves, or different types of coverings such as plastic or aluminum foil.
- Design a way to measure the temperature, such as by putting a thermometer inside a closed glass container. Where is the best place to put the thermometer?
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.