Paper 1

Question 1

One of the causes of the EOT?

Answer 1

Eccentricity of Earths Orbit
Obliquity of Ecliptic

Question 2

Design a suitable observing procedure that will allow the observer to produce a series of measurements of the EOT at different points in the year.

Answer 2

Equation of Time is difference between Apparent Solar Time and Mean Solar Time
Apparent Solar Time can be found from a sundial or shadow stick
Mean Solar Time can be found from a clock
Effect of longitude on AST needs to be allowed for
Need to ensure no direct viewing of Sun
Easier to use MST as independent variable as it is easier to assess when it has reached a whole number of minutes(unlike AST).

Question 3

A total solar eclipse is only visible from a few places on Earth but a lunar eclipse is visible from a large proportion of the Earths surface?

Answer 3

Moon is much smaller than cone of shadow behind Earth in a lunar eclipse
Moon fits almost exactly into line of sight ‘cone’ of rays to Sun in a solar eclipse
Comparison of shadow areas on Earth’s surface (night hemisphere of Earth v. tip of shadow cone).