The umbral shadow can produce the following eclipses: This means that, on their journey through space, both objects produce all 3 types of shadows.ĭepending on which shadow type is involved, we can experience 3 different types of solar eclipses and 3 different types of lunar eclipses on Earth: Umbra Eclipses The Sun is a very large light source, its diameter exceeding that of both the Earth and the Moon. Our solar system resembles the set-up of the last experiment. You have just entered the basketball's antumbra. A ring of light will appear around the ball as the outer rim of the lamp comes into view. At some point, the basketball will appear smaller than the lamp. However, as you move away from the ball, its apparent size decreases. You are within the umbra, and the lamp is invisible. As long as you are fairly close to it, the ball's apparent size exceeds the lamp's apparent size. Imagine once more that you are looking at the lamp from behind the ball. In this experiment, the light source is another round lamp, but this time it has twice the ball's diameter. Rule: If the diameter of the light source is larger than the diameter of the object, a 3rd type of shadow appears where the cone-shaped umbra ends: the antumbra. If the diameter of the light source exceeds that of the object, an antumbra appears. You are standing on the side of the ball exactly opposite to the light source, facing it, so the order is: light source – basketball – you. Both the light source and the basketball are at the same height as your head. So imagine that you are in a windowless room with 1 light source and 1 round object that casts a shadow, say, a basketball. However, their absolute size is irrelevant, so a basketball illuminated by a large lamp produces the same shadows as the Moon illuminated by the Sun. The number and types of shadows created by an opaque object depend on its size in relation to the size of the light source. To understand why the Earth and the Moon have 3 types of shadows, let's start on a smaller scale. The umbra is the shadow's dark center portion, while the penumbra and the antumbra are different types of half-shadows. The type of eclipse we experience depends on the type of shadow that is involved. A solar eclipse may be total, partial, or annular a lunar eclipse may be total, partial, or penumbral. However, there are different types of solar and lunar eclipses. If the Moon's shadow falls on Earth, we get to see a solar eclipse the Earth's shadow falling on the Moon results in a lunar eclipse. The Moon's umbra, penumbra, and antumbra. Business Date to Date (exclude holidays).Reviewed in the United States □□ on 10 December 2011 Nice Style, Easy to Install, Needs to Be Wider A gloss white or other would be a nice addition to the product line. Overall, I like the folding hooks and the ease of install, but they could really use more spacing between each hook and maybe some additional colors instead of just natural. It they were about 6-7" apart, it would be much better. The hooks are only about 3-4" apart, so it is not pratical to hang too many bulky items (see my picture posted to this review), even with my kids small jackets and backpacks. My only gripe would be that it is pretty small. These screw into the wall and provide a much stronger base to mount the hooks onto. For the other hanging mount or if you can't find a stud, use a "wall gripper" type of anchor. With folding the hooks in and out, hanging and removing backpacks, coats, whatever, I can see the wall anchors working loose pretty quickly. Although it comes with wall anchors, if you can grab at least one stud, I would highly advise it. They include the screws plus wall anchors, so it is ready to go right out of the box. It doesn't match our decor, but I'll take function over form any day. I like the fact that the hooks fold in so that they don't protrude into the hall when not in use during the day, so I can move in and out of the hall freely without having to avoid getting caught by the hooks. I was looking for a coat hook for my kids backpacks and coats (ages 5 & 7) for our hallway by the back door.
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