The Reasons for the Seasons By Allegra Dickson
Vocabulary of the Seasons: 1. Axis- a line from the North Pole to the South Pole which is the fxed point around which the Earth rotates. The axis of the Earth is tilted 23.4 degrees and causes the seasons to change. 2. Orbit- Earth's orbit is it's elliptical path around the run. A complete orbit is the completion of a year. 3. Ellipse- a circle stretched out in one direction. The earth's orbit is an ellipse. 4. Prediction- a educated guess about what will happen in the future. 5. Observation- watching and taking note of things that happen around you.
...continued 6. Direct Sunlight- when the sun is directly above a certain part of the earth, they experience more intense heat.(summer) 7. Indirect Sunlight-when the sun hits a certain part of Earth on an angle, they experience less intense heat. (winter) 8. Equator- an imaginary line that divides the earth I half, North and South. 9. Northern Hemisphere- the area of the earth that is North of the Equator. 10.Southern Hemisphere- the area of Earth that is South of the Equator. 11. Equinox- happens twice a year, during Spring and Fall, when Earth's axis is tilted neither toward nor away from the sun. 12. Solstice- happens twice a year, during Winter and Summer, when the sun has reached either its northern or southern most position relative to Earth.
Emily and Jimmy were good friends. One day in September after school, they were playing outside. Emily stopped and wondered. What are you thinking about, Emily? Jimmy asked. Why do you think it gets cold when school starts? Emily asked. What do you mean? Asked Jimmy. Well, in the beginning of the school year, we can still wear shorts and tshirts. Then, when Halloween comes it gets a little bit colder and we need to wear warmer clothes.
Oh yeah! And during Christmas time we all need to wear hats, scarves and gloves because it's much colder outside. You know what else? It gets darker, faster too! Jimmy continued. Yeah, I know what you mean. When my mom picks me up from my friends' houses it feels like it's night time because it's dark! My favorite time of the year is the spring time when it gets warmer again! Then the sun stays out longer and I can wear shorts again!
So then what makes the seasons change? Jimmy thought for a moment, Maybe it has to do with time. Like, if you spend just enough time, a buzzer goes off somewhere. That means it's time to change seasons Emily and Jimmy looked at each other for a few seconds and began to giggle. Haha! I don't think that the seasons are on a timer that has a buzzer. And if they did have a buzzer, who would be in charge of changing the seasons? Emily said. She was right, the seasons are not controlled by anyone.
Hmm.. I know! Maybe it has something to do with how far away the Sun is from Earth throughout the year! Emily exclaimed. What do you mean, throughout the year? Jimmy asked her. Well, the Sun is the center of our Solar System, which means that all the planets orbit around it. So maybe when Earth orbits the sun, there are times when the Sun is farther away. That would be Fall and Winter.
Yeah! Maybe that's it! And when the Sun is closest to Earth, that's when we have Spring and Summer! Jimmy agreed. Suddenly, a voice spoke out that was not Jimmy or Emily. Now just a minute there kids, that's not why the seasons change. Emily and Jimmy looked around the backyard, but couldn't see anyone around them. The shrugged their shoulders in confusion. Look up here! said the voice.
Jimmy and Emily looked up to fnd that the sun was talking to them! Hi there, Jimmy and Emily. I was up here listening to you two talking about what causes the seasons to change. I want to help. Let me start by telling you that a great place to start is with predictions. Let me ask you a question. Would you believe me if I told you that I, the Sun, am actually closest to Earth on January 4th of each year? No way! That wouldn't make sense with our prediction that the Sun has to be farther away from Earth during Fall and Winter. Jimmy said.
It's actually true, said Sun, When Earth makes its orbit, or path, around me, the Sun, it is closest to me during the winter time. Let me explain by showing you Earth's orbit. Wait, Earth doesn't travel around the Sun in a circle? Emily asked. No, it doesn't. In fact, Earth travels around the Sun in a shape that it called and ellipse. An ellipse is close to the shape of a circle, but it isn't the same. It looks like a circle that's been a little stretched out in on direction, said Jimmy. That's what an ellipse is, Jimmy! Great observation
What's that line going diagonally through the earth? Asked Emily. Great question, Emily, replied the sun, I was just getting to that. Earth orbits, or revolves, around me on its axis. The axis is an imaginary line from the North to the South Pole and it shows that Earth is slightly tilted as it travels through it's orbit. Well, what does that have to do with the seasons? Jimmy asked. Earth orbits on its axis and that determines how much direct sunlight each part of the earth receives. If the earth didn't orbit on its axis, then we wouldn't have seasons. We would have the same weather conditions all through the year, Sun answered. Okay, so during the winter, what does the earth look like? The axis of the earth stays pointing in the same direction throughout its orbit around the sun. Because of this, certain parts of the earth receive different kinds of sunlight at a specific time.
During the Winter, the North Pole is tilted further away from me. So when I give off light and heat to the earth, the North Pole receives it on an angle and not directly. What's the difference between direct sunlight and receiving sunlight on an angle? asked Jimmy. Good question. When your part of the earth receives direct sunlight, that's when you experience warm weather, or Summer. When you receive sunlight on an angle, that's called indirect sunlight. That's when you experience colder weather, like you do in Fall and Winter. Take a look at the fashlight diagrams to see what I mean about direct and indirect sunlight.
When the Northern Hemisphere experiences Summer (direct sunlight), the Southern Hemisphere experiences Winter (indirect sunlight). So if we take another look at Earth's Orbit, we can see that the way the earth is tilted in its orbit determines the change of the seasons. For example, during our Summer season, Earth's North Pole is tilted toward the sun. That's when the Northern Hemisphere experiences direct sunlight, and Summer. Northern Hemisphere? What's that? Emily asked. Earth is split in half by the Equator, and imaginary line. This line divides the Earth into North and South, known as hemispheres, replied the sun. And the axis divides the earth into East and West! Jimmy exclaimed. That's right, Jimmy! You both live in the Northern Hemisphere and Western Hemisphere.
Okay, so that's how the seasons change, but how do you explain why the days are shortest in the winter and longest in the summer? Asked Jimmy. Oh yeah! I forgot about that! Emily cheered. I'm glad you asked, replied the sun. The tilted axis is also the reason why we have more hours of daylight in Spring and Summer and less during Fall and Winter.Since the sun is closest to Earth during the winter, when the North Pole is tilted away from the sun, the sun sits lower in the sky. That's why we have shorter days. In fact, the closer you live to the North Pole, the shorter your days are during Winter. During the summer, the sun is up higher in the sky. Because the sun is higher in the sky, you receive direct sunlight for a longer amount of time. This is why days are longer and hotter during Summer, answered the sun.
23.5 degrees is how much the Earth is tilted. Autumnal Equinox is another way of saying Fall. Vernal Equinox is another way of saying Spring. The word, 'Equinox' means that the earth's axis is tilting neither toward nor away from the sun. This is was causes the in-between weather during fall and spring. It's not too hot or too cold. Also, Equinox means equal in latin. The term is also used because around the this time, the hours of day and night are approximately equally as long. Wow, so it's kind of the opposite of what we thought, said Emily, that was kind of silly of us. As I said before, this goes for both you and Jimmy, the best way that we learn is by testing out our predictions. You both made a prediction based on your observations. Scientists do the very same thing when they study the world. It's how we learn!
Wow! We learned so today! I can't wait to go back to school and tell everyone how the seasons work! Our teacher will be so impressed! Emily was so excited that her question had been answered, and by the Sun too! What more could she have asked for? Yeah, well we better get in our playing time now! The days are getting shorter! Joked Jimmy. Jimmy and Emily, I am so glad that I helped you today! I'll just be up here watching over you until I set. Have fun! Jimmy and Emily played until sunset and went inside for dinner, when they explained what they had learned to their parents.
Standards: Grades 3-5 A. 3.3. Broad Concept: Objects in the sky move in regular and predictable patterns. As a basis for understanding this concept Students: Observe and describe the apparent motion of the sun and moon over a time span of one day. Using a globe, demonstrate how the Earth rotates on its axis every 24 hours, producing the night- and-day cycle. B. 4.1 Broad Concept:Scientifc progress is made by asking relevant questions and conducting careful investigations. Explain how scientifc thinking can be distorted by strong feelings, and explain why and when it is appropriate or necessary to separate emotions from the reasoning process. C. 5.5 Broad Concept: Students should relate to the earth as a planet in our solar system. Students should be able to : Describe the Earth as part of a system called the solar system, which includes the sun (a star), planets, comets, asteroids, and many moons. 5.5.2. Recognize that the Earth is the third planet from the sun in our solar system. 5.5.3. Demonstrate how the Earth orbits the sun in a year s time, and Earth rotates on its axis about once every 24 hours.