Meera's daytime Moon

It was Makar Sankranti, and Meera was in Ahmedabad for the Patang Mahotsav, the International Kite Festival. Looking up at a sky full of kites, she noticed the Moon shining in the daytime!

She was surprised: she'd always thought the Moon came out only at night. It wasn't a full circle either, though that surprised her less, because she knew its shape changes from night to night.

It set her thinking. The Moon is a ball, and it shines by reflecting sunlight. So why don't we see the whole Moon every night? Could it be an eclipse? No: eclipses are rare and short, and the Moon's shape changes every month.

Find the pattern yourself (Activity 11.1). It works best if you start a month or more before you study this chapter. Begin at sunrise on the day after a full Moon, when the Moon is easy to spot low in the west.

Make a table like Table 11.1. Each day write the date, whether you saw the Moon at sunrise or sunset, and shade a circle to show the bright part you could see.

From the second day, also note:

• is the bright part bigger or smaller than yesterday?
• is the Moon closer to or farther from the Sun in the sky than yesterday?

After about 15 days you may not see it at sunrise any more, so carry on at sunset for the next 15 days.