Students will certainly investigate how different surfaces of the earth reflect and also absorb heat and apply this understanding to real-world situations.

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Learning Objectives

Students will recognize that the physical qualities of the Earth"s surface affect the way that surface absorbs and also releases warmth from the Sun.

Next Generation science Standards

Disciplinary core Idea MS & HS PS4.B - Electromagnetic RadiationDisciplinary main point Idea MS & HS ESS2.D - Weather and ClimateScience and also Engineering exercise 2 - Developing and also Using ModelsScience and also Engineering exercise 4 - examining and Interpreting DataPerformance Expectation MS PS4-2 - Develop and use a design to define that waves room reflected, absorbed, or sent through assorted materials.

Materials

For a course demonstration or because that each team that students:

Three pie pans or dishesDark potting soilLight-colored sand or perliteWaterThree thermometersReflector desk lamp with incandescent light bulbWatch v a 2nd hand

For every student:

Graph paperColored pencilsHeating and Cooling Data Tables (See the "Student" tab that this activity.)

Preparation

Print the Heating and also Cooling Data Tables uncovered in the "Student" tab ~ above this activity page. This activity can it is in done as a class demonstration or in groups that 3-4 students. If you room doing it together a demonstration, you"ll need one collection of materials and graph document and data tables for each student. If the task will be done in small groups, each team will need supplies. Check the light bulbs come ensure they create heat. Usage incandescent light bulbs rather of LED or CFL bulbs. 

Directions

Introduce the activity.Help students think about what they already know around how the color and type of material affects how warm it it s okay in the sunshine. For example, questioning students, "When that is a warm day, what color shirt would certainly you wear to keep cool and why? and"During the summer, what would certainly it feel choose to to walk on asphalt or gravel v no shoes?"Explain that, in this activity, lock will discover how different varieties of surfaces found at the Earth"s surface ar (such as sand, soil, and water) warmth up once the Sun"s energy reaches them, and how they cool down once out that the sunshine.Note that this experiment uses materials to design sunshine and Earth materials. Display students the materials and also explain how each relates come the planet system. (The lamp to represent the sun in this model. The sand represents beaches, sand dunes, and also rocks. The potting soil represents large areas of soil outdoors. And also the water to represent lakes, rivers, and the ocean.)Fill the pie pans come the very same level, one v dark soil, one v light sand, and also one through water. (If small groups room doing this task on their own, distribute gives to students.)Place the pie pans on a table or desk and position the lamp about 12 inches over them. (Do not turn on the desk lamp yet.)

Place a thermometer right into each pie pan, with the bulb just under the surface of the substance (soil, sand, or water) in the pan.Provide students v data tables and explain exactly how the tables relate to the experimental design.Have students document the temperature right prior to they rotate on the desk lamp (Time=0), entering the number right into their data table.Turn top top the lamp and instruct students to document the temperature every minute in the three pie pans for ten minutes.After ten minutes, rotate the desk lamp off and also instruct students to proceed recording temperatures every minute for ten minutes.Have college student graph the temperature data making use of graph paper and fancy pencils. Have actually students compose a subtitle for your graph that defines how the three various materials change in temperature over time.If several teams performed the experiment at the very same time, have teams compare their graphs as they talk about findings.

Optional Extension:

Have college student design and conduct their own research right into the influence of surface on temperature comparing planet surfaces that interest them (such together colored soils, dry and wet soils, grass, dry leaves, or different types of coverings such together plastic or aluminum foil). Have students to compare the data with these brand-new surfaces contrasted to the offered surfaces (water, irradiate soil, dark soil). Keep in mind that the data may not be similar due to variations in speculative design, together as differences in light bulb temperature and also height the the lamp.

Observations and also Questions

Which product absorbed much more heat in the first ten minutes?Answer - Dark soil (dark-colored surfaces absorb most of the radiation rather of reflecting)Which material shed the most warmth in the critical ten minutes?Answer - Dark soil (the surface ar that absorbs the most heat, additionally emits the most heat)Imagine the it"s summer and also that the sunlight is shining on the ocean and on a stretch the land.Which will warmth up more during the day?Answer - The floor heats up much more than the ocean throughout the day. The darker-colored surface, the land, absorbs an ext of the Sun"s radiation contrasted to the very reflective surface ar of the ocean.Which will cool much more slowly in ~ night? Explain.Answer - The s will cool much more slowly in ~ night due to the fact that surfaces the reflect many the radiation will additionally emit much less radiation (analogous to inquiry 2)Imagine 3 cities in the desert, all at around the exact same altitude and also latitude. I m sorry city would certainly likely have actually the highest possible average summer waiting temperature and also why?

One city (A) is surrounding by a dark-colored rocky surface.

Another city (B) is surrounding by a light-colored sandy surface.

The third city (C) is developed on the leaf of a large man-made desert lake.

Answer - City A will certainly likely have actually the highest average air temperature because it has the darkest floor surface. Darker land surfaces absorb higher amount the radiation and this absorption leader to rise in the temperature.

The Earth"s surface ar tends to lose warmth in winter. I m sorry of the above cities would have actually the warmest average winter temperature? Why?Answer - City C (large man-made desert lake).A great reflector (desert lake) is a negative absorber (and a negative emitter) the radiation.Since the sun is around 93 million mile from the earth and space has no temperature, how do we obtain heat indigenous the Sun?

Background

Heat Transfer

Of the energy that get the earth from the Sun, a tiny amount is absorbed by the atmosphere, a larger amount (about 30%) is reflected earlier to room by clouds and also the Earth"s surface, and most of that is absorbed at the planet surface and then released as heat. 

Energy is transferred in between the Earth"s surface and also the atmosphere in a selection of ways, including radiationconduction, and convection. The graphic listed below uses a camp range to summary the miscellaneous mechanisms of warmth transfer. If you to be standing next to the camp stove, you would be warmed through the radiation emitted by the gas flame. A section of the radiant energy generated by the gas flame is soaked up by the frying pan and also the pot that water. By the process of conduction, this power is transferred with the pot and also pan. If you reached for the metal handle of the frying pan without using a potholder, you would burn her fingers! as the temperature that the water in ~ the bottom that the pot increases, this class of water moves upward and also is changed by cool water descending native above. Thus convection currents the redistribute the newly acquired power throughout the pot space established.

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As in this simple example utilizing a camp stove, the heating of the Earth"s atmosphere requires radiation, conduction, and also convection, all emerging simultaneously. A basic tenet of meteorology is the the sunlight warms the ground and the ground warms the air. This activity focuses on radiation, the process by i beg your pardon the sun warms the ground. Power from the sunlight is the driving force behind weather and also climate.

Radiation

What perform trees, snow, cars, horses, rocks, centipedes, oceans, the atmosphere, and you have in common? each one is a source of radiation to part degree. Most of this radiation is invisible to humans yet that does no make it any type of less real.

Radiation is the transport of power by electromagnetic tide motion. The transport of energy from the Sun across nearly empty an are is achieved primarily by radiation. Radiation wake up without the joining of a physics substance together the medium. The sun emits countless forms that electromagnetic radiation in varying quantities.

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About 43% of the total radiant energy emitted indigenous the sunlight is in the visible parts of the spectrum. The mass of the remainder lies in the near-infrared (49%) and also ultraviolet section (7%). Much less than 1% the solar radiation is emitted together x-rays, gamma waves, and also radio waves.

A perfect radiating body emits power in all feasible wavelengths, but the wave energies space not emitted equally in every wavelengths; a spectrum will show a distinct maximum in power at a details wavelength depending upon the temperature the the radiating body. Together the temperature increases, the maximum radiation occurs at shorter and much shorter wavelengths. The hot the radiating body, the much shorter the wavelength of best radiation. For example, a really hot metal rod will certainly emit visible radiation and also produce a white glow. Top top cooling, it will certainly emit more of its energy in longer wavelengths and will light a reddish color. Eventually, no light will certainly be provided off, but if you place your hand close to the rod, the infrared radiation will certainly be detectable together heat.

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The amount of energy took in by things depends top top the following:

The object"s absorptivity, which, in the visible selection of wavelengths, is a duty of that color The soot of the radiation striking the object

Every surface ar on planet absorbs and also reflects energy at varying degrees, based on its color and texture. Darker-colored objects absorb more clearly shows radiation, conversely, lighter-colored objects reflect more visible radiation. 

Albedo

Albedo is the lot of power reflected by a surface ar without being absorbed. Things with high albedo shows the bulk of the radiation while an object with low albedo reflects only a small amount of incoming radiation but absorbs the bulk of the radiation.

Think about being outside and also how various materials reflect or absorb the incoming radiation. White-colored surfaces together white repaint reflect many of the radiation and therefore the albedo worth is about 1. Dark-colored surface such together gravel and also asphalt absorb many of the radiation and also have short albedo values closer to 0. This likewise explains why darker-colored surface have greater temperatures. Because that example, in summer black color asphalt roads can be scorching hot. As urban grow, and asphalt, concrete, and also dark roofs change the vegetation, these urban surfaces absorb—rather than reflect—the Sun"s heat, resulting in surface temperatures and also urban air temperatures to rise. This is known as the urban warm island effect. 


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The city that Phoenix, Arizona, has made an effort to paint an ext roofs white to combat the urban warm island effect. The aerial view of Phoenix illustrates the various land surface such as water (river located at bottom that image), soil and rock (brown), vegetation (green), structures with white roofs, roads, and also an airport (lower right).Credit: Google Earth