history of oceanography Flashcards
what is the degrees of latitude
line goes from left to right (measures north to south)
what is the degrees of longitude
line goes from top to bottom (measures east to west)
what is 1 degree of latitude
130km wherever you are on the planet
what is 1 degree of longitude
130km – the 1 degree compresses and becomes smaller as you move you move north or south of the equator
what is 0 degree of longitude
datum point
what does Polynesian map 1500BC show
direction of winds, wave patterns (crossing lines) + islands
- When waves hit land they diffract and bend around them – interference patterns
- become apart of research done today
what is the old technique for Navigation in latitude and what does it look at
using your hand and stars to look at distance between horizon + polaris in the sky – get indication of how far north or south you are
- north (+), south (-)
what is the new method for Navigation in latitude and what does it look at
sextance - measure angles of things from the horizon
Latitude = angle between horizon + the sun at midday
how to use time to do longitude navigation and how did it come about
The Longitude Act 1714 - John Harrison’s sea clock
- Use sextance to determine when the sun is at its highest point in the sky
- Based on that you know when its midday where you are + what time it is in Grenich – use difference in time to calculate how far the earth has spun in that period
- 1 hour = 15 degrees of longitude – allows to accurately pinpoint where you are on the chart
who was involved in the classical era of tides
Aristole
Pytheas of Massalia
The Venerable Bede
Simon Stevin
Isaac Newton
what did aristole discover in the classical era
Noted semi-diurnal tidal variation - Suggested this was due to weather
what did Pytheas of Massalia discover in the classical era
Travelled into the North Atlantic - Observed changes in tidal variation in different places
what did The Venerable Bede discover in the classical era
Author of the Ecclesiastical History of the English People - Reported that tidal heights and times vary between places
what did Simon Stevin discover in the classical era
Dutch scientist - Explained the timing of tides using the phases of the moon
what did Isaac Newton discover in the classical era
Author of Philosophiæ Naturalis Principia Mathematica
Explained tides using gravitation (moon pull)