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This activity, similar to Activity 11.5, is to be set up by your teacher. A mirror can be used to project an image of the IVE Sun onto a wall. However, holding it at the correct angle D EEPER throughout a solar eclipse can be diﬃcult. To solve this, make a movable stand for the mirror. Use a hollow ball with a small hole, half-ﬁll it with sand (to keep it stable), and attach a small mirror (such as an embroidery mirror) to it. Place the ball on a circular ring, like an adhesive tape ring, so it can be turned around easily. Adjust it until the Sun’s image appears on a wall or screen. Fig. 12.15 shows this set-up where the mirror is ﬁxed to a green ball. Caution—This activity should be performed strictly under supervision of a teacher. Take care not to direct the reﬂected light beam in anyone’s eyes. People have observed eclipses and maintained records since ancienttimes.Whenthereasonsforeclipseswerenotknown,they feared the occurrence of eclipses. As you can imagine, something blocking the Sun, the main source of heat and light on the Earth, even for a brief period of time, would have been extremely concerning. Many superstitions were attached to solar eclipses in various parts of the world related to the activities that could not be carried out during eclipses—such as eating, cooking, or going out of home. But now that we know the reason why a solar eclipse occurs, we need not fear these events as long as we do not look at the Sun directly. In fact, scientists go around the world to observe the eclipses from wherever these are observable. The eclipses provide them an opportunity to study phenomena that cannot be observed otherwise. e d FASCINATING FACTS r AneclipseisknownasgrahaninSanskritandinmanyIndianlanguages. G Many ancient Indian astronomical texts provide calculations to c predict eclipses. The best known and most referred text is the Surya n c Siddhanta, which is written in the classical Sanskrit poetry tradition f in rhythmic shlokas. o o b 12.3.2 Lunar eclipse x T As the Moon revolves around the Earth, sometimes the Earth can y block the sunlight from reaching the Moon. This is known as a i i lunar eclipse. On such days, we see the Earth’s shadow falling on u the full disc of the Moon. Fig. 12.16 shows the arrangement of the C Sun, the Earth, and the Moon during a lunar eclipse. 182 Reprint 2026-27