8.3.2.1 Sun as Energy Source
Explain how the combination of the Earth's tilted axis and revolution around the sun causes the progression of seasons.
Recognize that oceans have a major effect on global climate because water in the oceans holds a large amount of heat.
Explain how heating of the Earth's surface and atmosphere by the sun drives convection within the atmosphere and hydrosphere producing winds, ocean currents and the water cycle, as well as influencing global climate.
Overview
MN Standard in Lay Terms
The earth's climates and weather patterns are the result of uneven heating of the earth's surface by the sun. The tilted axis of the earth means that different areas receive a different amount of solar radiation throughout the day and the year, producing seasons. This energy from the sun is absorbed and re-radiated by the various surfaces of the earth. The resulting differences in temperature drive convection in both the atmosphere and the oceans, which allows the heat to be transferred to other areas of the earth.
Big Idea
3.1 The four major systems of Earth are the geosphere, hydrosphere, atmosphere, and biosphere. The geosphere includes a metallic core, solid and molten rock, soil, and sediments. The atmosphere is the envelope of gas surrounding Earth. The hydrosphere includes the ice, water vapor, and liquid water in the atmosphere, the ocean, lakes, streams, soils, and groundwater. The biosphere includes Earth's life, which can be found in many parts of the geosphere, hydrosphere, and atmosphere. Humans are part of the biosphere, and human activities have important impacts on all four spheres.
3.2 All Earth processes are the result of energy flowing and mass cycling within and between Earth's systems. This energy is derived from the sun and Earth's interior. The flowing energy and cycling matter cause chemical and physical changes in Earth's materials and living organisms. For example, large amounts of carbon continually cycle among systems of rock, water, air, organisms, and fossil fuels such as coal and oil.
3.3 Earth exchanges mass and energy with the rest of the Solar System. Earth gains and loses energy through incoming solar radiation, heat loss to space, and gravitational forces from the sun, moon, and planets. Earth gains mass from the impacts of meteoroids and comets and loses mass by the escape of gases into space.
3.6 Earth's systems are dynamic; they continually react to changing influences. Components of Earth's systems may appear stable, change slowly over long periods of time, or change abruptly with significant consequences for living organisms.
3.7 Changes in part of one system can cause new changes to that system or to other systems, often in surprising and complex ways. These new changes may take the form of "feedbacks" that can increase or decrease the original changes and can be unpredictable and/or irreversible. A deep knowledge of how most feedbacks work within and between Earth's systems is still lacking.
3.8 Earth's climate is an example of how complex interactions among systems can result in relatively sudden and significant changes. The geologic record shows that interactions among tectonic events, solar inputs, planetary orbits, ocean circulation, volcanic activity, glaciers, vegetation, and human activities can cause appreciable, and in some cases rapid, changes to global and regional patterns of temperature and precipitation.
5.3 Water's unique combination of physical and chemical properties are essential to the dynamics of all of Earth's systems. These properties include the manner in which water absorbs and releases heat, reflects sunlight, expands upon freezing, and dissolves other materials.
Earth Science Literacy: The Big Ideas and Supporting Concepts of Earth Science.
MN Standard Benchmarks
8.3.2.1.1 Explain how the combination of the Earth's tilted axis and revolution around the sun causes the progression of seasons.
8.3.2.1.2 Recognize that oceans have a major effect on global climate because water in the oceans holds a large amount of heat.
8.3.2.1.3 Explain how heating of the Earth's surface and atmosphere by the sun drives convection within the atmosphere and hydrosphere, producing winds, ocean currents and the water cycle, as well as influencing global climate.
The Essentials
Ron Tandberg, cartoonist
Structure of the Earth System
Global patterns of atmospheric movement influence local weather. Oceans have a major effect on climate, because water in the oceans holds a large amount of heat. (9F)
Earth In the Solar System (Unifying Concepts)
Most objects in the solar system are in regular and predictable motion. Those motions explain such phenomena as the day, the year, phases of the moon, and eclipses.(2)
The sun is the major source of energy for phenomena on the earth's surface, such as growth of plants, winds, ocean currents, and the water cycle. Seasons result from variations in the amount of the sun's energy hitting the surface, due to the tilt of the earth's rotation on its axis and the length of the day. (2)
- AAAS Atlas:
The Physical Setting: Weather and Climate
Benchmarks of Science Literacy
B. The Earth: By the end of the 8th grade, students should know that:
Everything on or anywhere near the earth is pulled toward the earth's center by gravitational force. 4B/M
Water evaporates from the surface of the earth, rises and cools, condenses into rain or snow, and falls again to the surface. The water falling on land collects in rivers and lakes, soil, and porous layers of rock, and much of it flows back into the oceans. The cycling of water in and out of the atmosphere is a significant aspect of the weather patterns on Earth. 4B/M7*
Thermal energy carried by ocean currents has a strong influence on climates around the world. Areas near oceans tend to have more moderate temperatures than they would if they were farther inland but at the same latitude because water in the oceans can hold a large amount of thermal energy. 4B/M9*
The temperature of a place on the earth's surface tends to rise and fall in a somewhat predictable pattern every day and over the course of a year. The pattern of temperature changes observed in a place tends to vary depending on how far north or south of the equator the place is, how near to oceans it is, and how high above sea level it is. 4B/M12**
The number of hours of daylight and the intensity of the sunlight both vary in a predictable pattern that depends on how far north or south of the equator the place is. This variation explains why temperatures vary over the course of the year and at different locations. 4B/M13**
The earth has a variety of climates, defined by average temperature, precipitation, humidity, air pressure, and wind, over time in a particular place. 4B/M14**
Misconceptions
- Seasons are caused by the earth's distance from the sun.
- Clouds block wind and slow it down.
- Cold temperatures produce fast winds.
- Infrared is "heat radiation," not light.
- Infrared is the only type of light that, when absorbed, causes objects to heat.
- Infrared light is not a kind of heat.
- Heat is a substance which can be added to or removed from an object. Heat makes things rise.
- Cold is the opposite to heat.
- The greenhouse effect is caused when gases in the atmosphere behave as a blanket and trap radiation which is then re-radiated to the earth.
- Absorption by the glass in greenhouses is the main factor responsible for higher temperatures inside.
- Global warming and the greenhouse effect are the same thing.
- The greenhouse effect is bad and will eventually cause all living things to die.
Children's misconceptions about weather: A review of the literature.
Additional discussion on common misconceptions about climate and heat transfer
Vignette
Funny Water
In this example, Mr. B makes his plans using his knowledge and understanding of science, students, teaching, and the district science program. His understanding and ability are the results of years of studying and reflection on his own teaching. He usually introduces new topics with a demonstration to catch the students' attention. He asks questions that encourage students to develop understanding and designs activities that require students to confirm their ideas and extend them to situations within and beyond the science classroom. Mr. B encourages students to observe, test, discuss, and write by promoting individual effort as well as by forming different-sized groups of students for various activities. Immense understanding, skill, creativity, and energy are required to organize and orchestrate ideas, students, materials, and events the way Mr. B. does with apparent ease. And Mr. B. might repeat an activity five times a day, adapting it to the needs of different classes of students, or he might teach four other school subjects.
[This example highlights some components of Teaching Standards A, B, D, and E; Professional Development Standard C; 5-8 Content Standard A and B; Program Standards A, B, and D; and System Standards D.]
Mr. B. was beginning a unit that would include the development of students' understanding of the characteristic properties of substances such as boiling points, melting points, solubility, and density. He wanted students to consolidate their experiences and think about the properties of substances as a foundation for the atomic theories they would gradually come to understand in high school. He knew that the students had some vocabulary and some notions of atomicity but were likely not to have any understanding of the evidence of the particulate nature of matter or arguments that support that understanding. Mr. B. started the unit with a study of density because the concept is important and because this study allowed him to gather data on the students' current understandings about matter.
As he had done the year before, he began the study with the density of liquids. He knew that the students who had been in the district elementary schools had already done some work with liquids and that all students brought experience and knowledge from their daily lives. To clarify the knowledge, understanding, and confusion students might have, Mr. B. prepared a set of short exercises for the opening week of the unit of study.
For the first day, he prepared two density columns: using two 1-foot-high, clear plastic cylinders, he poured in layers of corn syrup, liquid detergent, colored water, vegetable oil, baby oil, and methanol. As the students arrived, they were directed into two groups to examine the columns and discuss what they saw. After 10 minutes of conversation, Mr. B. asked the students to take out their notebooks and jot down observations and thoughts about why the different liquids separated.
When the writing ceased, Mr. B. asked, ''What did you observe? Do you have any explanations for what you see? What do you think is happening?" He took care to explain, "There are no right answers, and silence is OK. You need to think." Silence was followed by a few comments, and finally, a lively discussion ensued.
It's pretty
How do you get the colors to stay apart?
Like the ones on top are lighter or something like that.
The top looks like water.
I think the bottom liquids are heavier; they sink to the bottom.
It separated into different layers because each has different densities and they sit on top of each other.
"What do you mean by density?" asked Mr. B.
It's how packed the particles are.
This one is thick so it's on the bottom. This one is thinnest.
Doesn't oil have lighter density than water?
If we put a thicker liquid in, it would go to the bottom.
There's more of this one that's on the bottom.
The atoms in some are heavier than the ones in others.
Mr. B. realized how many different ways the students explained what they saw, for example, thickness and thinness, heaviness and lightness, more and less, different densities and atoms. The discussion gave him a sense for what the students were thinking. It was clear to him that the investigations he had planned for the following weeks to focus more closely on density would be worthwhile.
Mr. B. divided the class into seven groups of four the next day. On each of the group's tables were small cylinders. Mr. B warned the students not to drink the liquid. Each group was to choose one person to be the materials manager and one to be the recorder as they proceeded to find out what they could about the same liquids used the day before (all of which were available on the supply table). Only the materials manager was to come to the supply table for the liquids, and the recorders kept track of what they did. Forty minutes later, Mr. B. asked students to clean up and gather to share their observations.
Every group identified some of the liquids. The water was easy, as was the vegetable oil. Some students knew corn syrup, others recognized the detergent. Several groups combined two and three liquids and found that some of them mixed together, and others stayed separate. Some disagreements arose about which liquid floated on which. Mr. B. suggested that interested students come back during their lunch time to try to resolve these disagreements. One group replicated the large cylinder, shook it vigorously, and was waiting to see whether the liquids would separate. Mr. B. asked that group to draw what the cylinder contents looked like now, put it on the windowsill, and check it the next day.
Mr. B. began the third day with a large density column again. This time he gave a small object to each of four students-a piece of wood, aluminum, plastic, or iron. He asked the class to predict what would happen when each of the four objects was released into the column. The students predicted and watched as some objects sank to the bottom, and others stopped somewhere in the columns.
"What do you think is going on?" asked Mr. B. "How can you explain the way these objects behaved? I don't want answers now," he went on, "I want you to try out some more things yourselves and then we'll talk.'' He then divided the class into four groups and gave each a large density column with the liquid layers. The students worked in their groups for 30 minutes. The discussion was animated as different objects were tried: rubber bands, a penny, a nickel, a pencil,
When we dropped something lighter in, it stopped near the top.
The rubber band is lighter than the paper clip. The paper clip is heavy so it drops down.
The rubber band has buoyancy, if you know what that means.
The nickel went all the way to the bottom because it's heavier, but the pencil wouldn't go into the last layer because it was too thick. The pencil is wood and it's lighter; the nickel is silver and it's heavier.
The nickel is denser than the pencil.
Mr. B. listened to these observations and encouraged the students to respond to one another. Occasionally he asked for a clarification-"What do you mean by that?" "How did you do that?" His primary purpose was to hear the students' ideas and encourage them to explain them to one another.
The next day he began the last of the introductory experiences. When the students came in, Mr. B. asked them to divide into their four groups and go to the tables with the density columns. Beside each column were several pieces of wood of different sizes. Students were to think and talk about what the pieces might do in the column, try them out, have more discussion, and write down some of their ideas in their science notebooks.
When enough time had passed, Mr. B. called the groups together and asked for some volunteers to read from their notebooks. Some students were struggling with what they had seen:
They stuck in the middle of the column.
The pieces are not the same weight. The bigger ones are heavier. I don't know why they all stopped in the middle.
Others seemed to understand. One student read,
If you have a block of wood and cut it into millions of pieces, each piece would have the density of the original block. If that block of wood weighed one gram and you cut it into a million pieces the weight would change. But no matter how many times you cut something, the density will not change.
When this statement was read Mr. B. asked how many people agreed with it. Most students quickly asserted "yes." But how sure were they? Mr. B. pulled out a piece of wood larger than any of those that the students had tried. "What would happen if this piece of wood were dropped into the column?" Some students said immediately that it would stop where the smaller pieces had. Others were not quite so sure. This piece was quite a bit bigger. One student asked for a show of hands. Twelve students thought this big piece of wood would sink farther and 16 thought it would sink to the same level as the others. Mr. B. dropped it in. It stopped sinking where the others had. There were a few "yeahs," a few "what's," and some puzzled looks.
As a final teaser and check on students' understanding, Mr. B. brought out two transparent containers of colorless liquids. He asked the class to gather around, took a candle and cut two quite different-sized pieces from it. The students were asked to predict what would happen when the candle pieces were put in the liquids. Mr. B. dropped the pieces into the columns: In one container the big piece sank to the bottom; in the other, the small one floated on the top. Some students had predicted this result, saying that the bigger one was heavier and therefore would sink. Others were perplexed. The two pieces were made of the same wax so they shouldn't be different. Something was wrong. Were the two liquids really the same? Mr. B. removed the pieces of wax from the containers and reversed them. This time the little one sank and the big one floated. "Unfair," came a chorus of voices. "The liquids aren't the same."
Mr. B. had used water and isopropyl alcohol. But he noticed several students were willing to explain the sinking of the larger piece of candle and not the smaller by the difference in the size of the piece.
Mr. B. closed the lesson by summing up. They had seen the density column and worked with the liquids themselves; they had tried floating objects in liquids; they had seen the pieces of wax in the liquids. What was the explanation for all these phenomena? For homework that night he asked them to do two things. They were to think about and write down any ideas they had about what was happening in all these experiences. He also asked them to think about and write about examples of these phenomena in their daily lives. After the students shared some of their observations from outside the classroom, Mr. B. would have the students observe as he boiled water to initiate discussion of boiling points.
The understanding of energy in grades 5-8 will build on the K-4 experiences with light, heat, sound, electricity, magnetism, and the motion of objects. In 5-8, students begin to see the connections among those phenomena and to become familiar with the idea that energy is an important property of substances and that most change involves energy transfer. Students might have some of the same views of energy as they do of force-that it is associated with animate objects and is linked to motion. In addition, students view energy as a fuel or something that is stored, ready to use, and gets used up. The intent at this level is for students to improve their understanding of energy by experiencing many kinds of energy transfer.
Resources
Suggested Labs and Activities
From the NOAA
Effect of Radiation on Temperature Changes of Land and Sea
This is a common activity when studying heating of the earth. There are many variations that could be done with activity. The addition of a container with soil or sand would allow the difference between heating of continents and oceans to be noted as well. This can also be done with many smaller containers to involve more students in collecting data and for repeatability. (8.3.2.1.2, 8.3.2.1.3)
A Science Netlinks lesson plan that incorporates a National Geographic online interactive addressing the reason for seasons. (8.3.2.1.1.)
A slightly more advanced and more inquiry based activity on understanding seasons and differences in temperature. (8.3.2.1.1, 8.3.2.1.2, 8.3.2.1.3.)
Instructional suggestions/options
Students can now consolidate their prior knowledge of the earth (as a planet) by adding more details (especially about climate), getting a firmer grasp of the geometry involved in explaining the seasons and phases of the moon, improving their ability to handle scale, and shifting their frame of reference away from the earth when needed. An inevitable paradox of the large scales involved is that an ocean that is difficult to imagine being 7 miles deep also can be considered a "relatively thin" layer on the earth's surface. Students should exercise their understanding of the paradox, perhaps by debating provocative questions such as "Is the ocean amazingly deep or amazingly shallow?"
Gravity, earlier thought of as acting toward the ground, can by now be thought of as acting toward the center of the spherical earth and reaching indefinitely into space. It is also time for students to begin to look at the planet's role in sustaining life-a complex subject that involves many different issues and benchmarks. In this section, the emphasis is on water and air as essential resources.
The cause of the seasons is a subtle combination of global and orbital geometry and of the effects of radiation at different angles. Students can learn part of the story at this grade level, but a complete picture cannot be expected until later.
Retrieved from: "Benchmarks On-Line"
Additional resources
A source for background information created specifically for teachers. The information is clear and concise and focused on this standard. (8.3.2.1.1, 8.3.2.1.2)
NSTA Science Objects are online interactive modules developed to increase teacher background knowledge.
Earth, Sun, and Moon: Our Moving Earth
Earth, Sun, and Moon: Earth's Seasons
Digital Library of Earth Systems Education DLESE's educational resources include lesson plans, scientific data, visualizations, interactive computer models, and virtual field trips-in short, any web-accessible teaching or learning material.
Vocabulary/Glossary
"Earth rotates on its axis and revolves around the Sun."
- atmosphere - the gases that surround a planet
- axis - the tilted, imaginary line around which the earth rotates;
- climate - the average pattern of weather for a particular region; elements include precipitation, temperature, humidity, sunshine, wind velocity, and other measures of the weather.
- convection - the movement caused within a fluid by the tendency colder, denser material to sink under the influence of gravity causing the hotter and therefore less dense material to rise
- equinox - the two times each year when the earth's position relative to the sun results in equal length day and night
- heat - a form of energy associated with the motion of atoms or molecules and capable of being transmitted through solid and fluid media by conduction, through fluid media by convection, and through empty space by radiation
- hydrosphere - all the earth's water found in the oceans, glaciers, streams, lakes, the soil, groundwater, and in the air.
- ocean currents - the continuous movement of the oceans water caused by wind and temperature differences
- revolution - one full orbit of the earth around the sun
- seasons - times of the year that have predictable weather patterns and lengths of day; caused by the earth's tilted axis and position in relation to the sun
- solstice - the two times each year when the earth's position relative to the sun results in the longest and shortest days of the year
- water cycle - the continuous movement of water through the earth's hydrosphere
- wind - air moving due to pressure differences in the atmosphere
- A very basic explanation of why the earth has seasons written for middle school aged students. Could be used independently by students. (8.3.2.1.1.)
- A variety of animations covering a wide range of weather and climate related topics. Each has the animation with additional explanations. (8.3.2.1.1, 8.3.2.1.2, 8.3.2.1.3.)
- A very basic animation of the earth's movement around the sun showing the tilted axis. (8.3.2.1.1)
Social Studies:
Wind and water currents influenced trade routes and settlement in the past.
The relative warmth of some ocean waters influenced where people settled by causing more habitable climates.
Many mapping activities showing currents and wind patterns, as well as global temperatures and seasonal changes.
Assessment
Assessment of Students
Bibliographic Citation: Keeley, P, Eberle, F, & Dorsey, C. (2008). Uncovering student ideas in science: another 25 formative assessment probes. Arlington, VA: National Science Teachers Association.
"Summer Talk" In this probe, misconceptions and understanding of the factors that cause the seasons on earth are assessed.
Bibliographic Citation: Keeley, P, & Tugel, J. (2009). Twenty-five new formative assessment probes. Arlington, VA: National Science Teachers Association.
"Global Warming" Although global warming is not specifically mentioned in the 8th grade standards, it is a topic that is generally discussed and relevant as a current event.
Additional assessment items available with a free registration from AAS
Assessment of Teachers
How could you demonstrate the cause of the season's on earth?
The ocean's play a major role in global weather patterns and climates. What factor do the properties of water have in this role?
Convection is a process that is involved in many earth processes and cycles. What are several ways to help students to understand this important concept?
Differentiation
According to Lee & Buxton (2010), a couple of approaches are useful for assisting English Language Learners (ELLs): teach content while fostering language development and draw on the so-called "funds of knowledge," which are students' personal experiences from home or community. For additional details on this see the original NSTA News posting and the official NSTA position statement.
Lee, O., & Buxton, C.A. (2010, April). NSTA Report: Teaching science to English language learners.
English Language Learners. Official NSTA Position Statement.:
There are some excellent resources available for students to learn more about the ocean system and current research that is being done. There are also many student-focused websites about the polar regions and oceans. Students could also learn more about the causes of hurricanes and share this information as a brief presentation to the class.
The website has many for specific classroom suggestions for SpEd, ELL
Students with disabilities. Official NSTA Position Statement.
The causes of the seasons are addressed in many trade books at multiple reading levels and could be used to provide the big ideas on an accessible reading level. Doing hands on activities involving differential heating and taking measurements that can be graphed to show these ideas will help all students to understand. Drawing on students experiences with the phenomena in this standard will help to make the connections that may increase understanding.
Parents/Admin
Administrators
This standard is looking at the earth's climates and weather patterns on a global scale. Globes will be used to demonstrate the differential heating of the earth's surface and the effect of the earth's tilt. The lights may be off while students use globes and lamps or flashlights to explore these ideas. Students may be drawing on world maps to show the movement of ocean currents and wind patterns. Since density plays a role in understanding convection, the teacher may also include activities that reinforce physical science concepts of temperature and density of water and air.
Many families still have the nightly local news on each evening. The weather forecast is an opportunity for students to share what they have learned. They may be able to explain where different air masses have formed and how the distant ocean is impacting weather in Minnesota.