Stand outside on a sunny day. Find your shadow.
What does your shadow look like? Is it all near your feet? Or does it stretch far away from you?
晴天站在外面，找你的影子。
你的影子是什么样的？它都在你脚边吗？还是它从你跟前伸得很远？
Your shadow does not look the same all day. Around noon, your shadow is short. In the early morning or afternoon, it looks very long. Your shadow changes as the time of day changes.
你的影子不是全天看起来都是一样的。中午，你的影子很矮。早上刚来到或下午快结束时，影子看起来非常长。你的影子随着这一天在变化。
Today we have clocks and watches to measure time. Long ago, people did not have these things. They measured time in other ways. One way was with shadows. They made timepieces called sundials.
今天，我们有钟表和手表来计时间。很久以前，人们没有这些东西，他们用别的方法来计时间。一种方法是用影子，他们做了计时器叫日晷。
A sundial has two main parts. The first part is a face marked with the hours. The second part is a pointer. The pointer casts a shadow on the face of the sundial.
一个日晷有两个主要部分。第一个主要部分是一张上面标有小时的表面。第二个主要部分是指针。指针在日晷的表面上投下影子。
How a Sundial Works
日晷怎样工作
A sundial needs sunlight to work. On a sunny day, the pointer on the sundial makes a shadow. The shadow falls on the sundial’s marked face. The mark tells what the time is.
日晷需要阳光才能工作。晴天，日晷上的指针投下影子。影子被投在日晷标了小时的表面上。标志显示几点。
To tell the time, the pointer must point north. The pointer also must tilt to get the most direct sunlight.
显示时间，指针必须指到北边。指针也必须倾斜。这样，阳光就能刚好照在指针上了。
Sundial Time
日晷时间
A sundial measures solar time. Solar means “of the sun.”
Solar time is not always the same as clock time. The number of minutes in a clock hour does not change. Each hour on a clock is 60 minutes long.
日晷计算太阳时间。Solar代表“太阳的”。
太阳时间不总是和钟表时间一模一样。钟表的一个小时里，分钟的数量不变。钟表上的每个小时都有60分钟。
Solar time is different. A solar hour has no minutes. There are always 12 solar hours between sunrise and sunset. However, the hours are longer in the summer than in the winter.
太阳时间是不同的，一个太阳小时没有分钟，日升和日落中间，总是有12个太阳小时。
无论怎样，小时在夏天时间比冬天时间更长。
Early Sundials
早期的日晷
Who made the first sundials?
Long ago in Egypt, people built tall thin towers. Like the pointer on a sundial, the tower cast a shadow. The shadow showed when it was morning and when it was afternoon.
谁制造了第一批日晷？
很早以前，在埃及，人们建造了又高又瘦的塔。就像日晷上的指针一样，塔投下影子。影子展示什么时候是早上，什么时候是下午。
The Egyptians made the first sundials with round, flat faces. Later, Greeks and Romans made sundials in many shapes and sizes.
埃及人做了第一批日晷，它们有着又圆又扁的表面。接着，希腊人和俄罗斯人做了许多形状和尺寸的日晷。
The Greeks made sundials shaped like bowls. The hour marks were in the hollow of the bowl.
Some Romans had sundials that were very small. They carried these sundials in their pocket. Sort of like a watch!
The early Chinese also made sundials. Their sundials measured the lengths of shadows.
希腊人做了形状像碗的日晷。小时的标记在碗的里面。
一些俄罗斯人有非常小的日晷。他们把这些日晷放在口袋里，就像手表一样！
古代的中国人也做日晷。他们的日晷测量影子的长度。
Sundials Today
今天的日晷
You can still see sundials in many places. Some people put them in their gardens. Sundials can be found beside building and in parks.
你仍然在许多地方能见到日晷，有些人把它们放到花园里。日晷能在建筑物旁边和公园里找到。
A sundial works anywhere the sun shines. There is a sundial on the planet Mars! It was carried there by the Mars Surveyor Lander in 2002.
日晷只在太阳发光的地方工作。星球火星上有一个日晷，它是2002年被火星测量着陆器带到那儿的。