M5.2 Flashcards
Who was Eratosthenes?
Eratosthenes was a Greek mathematician, astronomer, and geographer known for calculating the Earth’s circumference.
What method did Eratosthenes use to estimate the Earth’s circumference?
He used the angle of the sun’s rays at two different locations and the distance between them.
What was the approximate value of the Earth’s circumference calculated by Eratosthenes?
Eratosthenes estimated the Earth’s circumference to be about 39,375 kilometers (24,901 miles).
True or False: Eratosthenes was the first person to suggest that the Earth was round.
True.
What is the Doppler effect?
The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source.
Fill in the blank: The Doppler effect is commonly observed in _____ and _____ waves.
sound; light
Who is credited with the discovery of the Doppler effect?
Christian Doppler.
What happens to the pitch of a sound as the source moves towards an observer?
The pitch increases.
What is the significance of the Doppler effect in astronomy?
It helps in measuring the speed of stars and galaxies moving towards or away from the Earth.
True or False: The Doppler effect can only be observed in sound waves.
False.
Who discovered oxygen?
Joseph Priestley.
What year did Joseph Priestley discover oxygen?
1774.
What was the name of the gas that Priestley initially referred to as ‘dephlogisticated air’?
Oxygen.
Fill in the blank: Priestley’s discovery of oxygen was significant for _____ and _____ science.
chemistry; respiratory
What experiment did Priestley conduct to isolate oxygen?
He used a magnifying glass to focus sunlight on a sample of mercuric oxide.
True or False: Joseph Priestley was also a noted theologian.
True.
What did Priestley’s work contribute to the understanding of combustion?
He showed that oxygen is essential for combustion.
What is the relationship between the Doppler effect and redshift?
Redshift is a phenomenon related to the Doppler effect, indicating that an object is moving away from the observer.
What scientific principle did Eratosthenes’ work on Earth’s circumference help establish?
The principle of geometry and the concept of a spherical Earth.
Fill in the blank: The Doppler effect is important in _____ and _____ technology.
radar; medical imaging
What was one of the historical implications of Priestley’s discovery of oxygen?
It paved the way for the development of modern chemistry.
True or False: The measurements taken by Eratosthenes were based on assumptions that were later proven incorrect.
False; his measurements were remarkably accurate for his time.
What kind of waves does the Doppler effect apply to?
It applies to all types of waves, including sound, light, and electromagnetic waves.
Who were some of the contemporaries of Joseph Priestley in the field of chemistry?
Antoine Lavoisier and Henry Cavendish.
