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Sailing Away
Eratosthenes
The Seasons
100
The part of a ship that remains visible longer as it sails away.
What is the top or sail?
100
Eratosthenes observed a difference in this phenomenon that supported a round Earth on a tilted axis.
What are shadows.
100
This hemisphere receives more radiation from Sol during the Summer Solstice.
What is the Northern Hemisphere?
200
The "line" where the Earth appears to meet the sky/
What is the horizon?
200
The angle at which Sol's radiation strikes the Earth is called this.
What is solar incidence?
200
These lines run from West to East and measure the distance to the North or South of the Equator.
What are lines of latitude?
300
The point of view from which something is viewed.
What is perspective?
300
Although areas near the equator receive more intense radiation, areas closer to the poles can have greater areas illuminated. State the name for this phenomenon.
What is beam spreading.
300
The points in the Earth's revolution around the Sun when day lengths are the same in the Northern and Southern hemisphere.
What are equinoxes?
400
Increasing this allows an observer to see much farther on a curved Earth.
What is elevation or altitude?
400
Eratosthenes was attempting to measure this by comparing differing shadow lengths at different latitudes at different times of the year.
What is the circumference of Earth?
400
Increasing this measurement decreases solar incidence.
What is latitude?
500
Double Jeopardy: Write an explanation for why you are able to see a greater distance from a lighthouse, crow's nest, widow's walk, etc. on a curved Earth.
What is the change in perspective allows us to see over the horizon for a greater distance. The curvature of the Earth increases the distance across the surface between two points compared to the actual distance.
500
Double Jeopardy: If there are 800 kilometers between 2 columns which cast a shadow with 7 degrees difference in angle, what is the circumference of the Earth measure in kilometers? (You may round to the nearest 1000km.)
What is 41,000km?
500
Double Jeopardy: Write an explanation for the cause of seasons on Earth.
The declination of Earth is 23.5 degrees. As Earth orbits the Sun, this declination causes a difference in solar incidence to result in the Northern and Southern hemispheres depending on which hemisphere is oriented towards the Sun. This effect is increased because the curvature of the Earth prevents much of Sol's radiation from reaching the poles when the Northern or Southern hemisphere is tilted away from the Sun and causes more solar radiation to reach the poles when they are tilted towards the Sun. This causes weather patterns which produce seasonal variation in climate.