4: Sun Path
- Page ID
- 162996
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Lab Overview
In this lab you will use a Celestial Sphere model to explore the path of the sun for observers at different latitudes at different times of the year. You will focus on where the sun rises and sets (if at all), how long the sun is above the horizon (hours of daylight), and differences in the actual path of the sun, including its altitude at local noon.
Lab Goals
As a result of this lab, you should be able to:
- Identify how latitude and seasons (time of year) affect the rise and set azimuth of the sun
- Identify how seasons and latitude affect the hours of daylight
- Identify how latitude and seasons affect the overall path of the sun in the sky
Equipment and Setup
This lab requires the following equipment on each table.
- Celestial Sphere Model that you can manipulate
Submission Instructions
Submit a brief lab report that includes the following sections:
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Results
Include drawings of the sun path as viewed from the celestial sphere models and tables of data for sun measurements at different times of the year.
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Discussion
Use the CER format to identify multiple patterns relating the sun position and sun path during the day from different latitudes at different times of the year.
Using a Model Celestial Sphere
Background Information
Recall that you can set the latitude of the observer’s horizon by adjusting the latitude value to be at the top of the sphere. You can also use patterns relating the altitude of Polaris and/or the angle of the celestial equator to set the latitude.
There is a sun model on the sphere. Adjust the sun to match the month of the year that you want to model. You can create a sun path by starting the sun on the Eastern horizon, placing a dry erase marker on the celestial sphere at the sun location. Rotate the sphere and watch the sun rotate as well. Keep the marker at the spot on the Eastern horizon so that a curve is traced out as you rotate the celestial sphere.
Once you have your path drawn, you can measure that path. The celestial sphere has curves that resemble longitude with 1-hour spacings. Using these markings, you can estimate how many hours the sun is above the horizon.
Sun Path Instructions
- Adjust the angle of the Earth to represent the observable sky for a person who is at each of the following locations:
- 40o N
- 40o S
- Equator
- North Pole
- South Pole.
- Use different color markers to identify the sun path for the following months on the 21st of each month. If you finish all locations early, go back and add in the missing months:
- March
- June
- September
- December
- Record the rise and set azimuth for each path. If the sun never rises or never sets, write N/A.
- Measure the declination and the altitude of the sun at local noon.
- Measure the number of hours of daylight for each path
- Draw the paths on the Horizon Diagram Sketch
Discussion Questions
- Are there any months that have the same values for rise/set azimuth or sun declination?
- What affects sun declination more? Latitude or time of year (month)?
- Are there any months when the latitude does not significantly affect the rise and set azimuth?
- Are there any months when the latitude does significantly affect the rise and set azimuth?If so, what patterns do you notice about those azimuth values?
Discussion
Your discussion should make evidence-based claims about patterns, models, or other insights from your experiment. You likely have identified multiple claims that you can make and should write a separate (3-5 sentence) paragraph for each claim. Each paragraph should be organized in a Claim-Evidence-Reasoning format:
- Claim: A succinct articulation of a pattern or concept that you can support with data/observations.
- Evidence: A sentence or two that selects and summarizes measurements, descriptions, or patterns from your lab. Be as clear as possible. You might want to add labels or color-coding to your models to make it easy to refer to specific parts or components.
- Reasoning: Explain how the specific evidence you selected supports/justifies your claim. Imagine you are explaining it to someone who is not in this lab so they do not have the background information that you have.
Sun Path Question: How does the time of year affect the path of the sun at different locations on Earth?
- Discuss all of your ideas, then organize them into multiple small patterns.
- Write a CER for each small component of your answer to the overall question.