how to measure the moon's shadow

A Solar eclipse occurs when the Moon passes between the Earth and the Sun and casts a shadow in the Earth’s surface. How big is the shadow of the moon on the Eath’s surface? – The general understanding of an eclipse is a celestial body obstructed by the shadow of another celestial body. So, technically an eclipse is the blocking of light from one celestial body when it crosses the shadow ot another celestial body. A lunar eclipse occurs when Earth’s shadow falls on the Moon and blocks the Moon’s light.

The understanding of this defintion confirms to the general definition of an eclipse. But technically, solar eclipse is a special form of grafting, where a larger celestial body passes in front of a smaller celestial body. So is the moon bigger than the Earth or the Sun? The size is based on the perspective of the image generated due to the influene of distance.

A solar eclipse is a phenomenon that ocurs when the Moon passes between the Earth and the Sun. When the moon covers all the sun except the appearance of the sun’s outer ring, the phenomenon is a total solar eclipse.

A total solar eclipse occurs depending on the distance between these three celestian bodies, the Earth moving in its orbit around the Earth so that at one moment where the Mooin covers the entire sun then that is a total solar eclipse, if only part ot it is only a solar eclipse not total.

figure a total solar eclipse

Alhtough it rarely occurs, a total solar eclipse can be predicted every 18 months or about one or two years that will occur somewhere on the Earth’s surface. The nature school has been practiced how to make a model solar eclipse.

Then what is the size of the Moon’s shadow on the Earth’s surface when a total eclipse occurs. In thsi project, the Nature School will practice how to measure the shadow of the mooin during a total solar eclipse.

Learning Objective

The Learning objective of this project is to model the size of the Moon’s shadow during a total solar eclipse.


sheet of white copy paper

drawing compass





1. Fold the paper in half, long sides together.

2. Unfold the paper. Draw two arcs centered at opposite ends of the fold. One arc should have a 2-inch (5-cm) diameter and the other a 6-inch (15-cm) diameter. Label the larger arc “Sun” and the smaller arc “Earth.”

3. Using the pencil and ruler, draw two lines from where the fold line touches the surface of the Earth to the top and bottom edge of the Sun.

4. Lay the penny between the lines connecting the Earth and the Sun. Move the penny between the lines until you find the place where the penny fits snugly between the two lines.

5. Draw a circle around the penny and label it “Moon.”

6. Draw two horizontal lines from the Earth to the Sun so that they touch the top and bottom edges of the Moon.

7. Using the pencil, label the areas between the Moon and the Earth “Penumbra” and “Umbra.” Shade the umbra and penumbra as shown.

figure how to measure moon's shadow size


Shaded areas are formed between the Moon and the Earth. Only a small part of the dark shaded area touches the Earth.


A solar eclipse is when the Moon passes between the Sun and Earth. During a total solar eclipse, as demonstrated in this experiment, the Moon’s shadow reaches the surface of Earth and the Sun’s light is totally blocked for observers in the umbra (the inner, darker part of a shadow) of the Moon’s shadow, partially blocked for observers in the penumbra (the outer, lighter part of a shadow), and not blocked at all for observers outside the shadow. Because the Earth rotates, the Moon’s shadow sweeps a narrow path across the Earth’s surface.