1. Calendars
1. How many months are in a year? How many days? Most people would quickly answer that a year has 12 months
or 365 days. If you had asked these questions a couple of thousand years ago, however, you would have received
all kinds of different answers. This is because almost every civilization had its own way of measuring the passing
days. The 365-day calendar that much of the world uses today, the Gregorian calendar, was not invented until
1582.
2. Today we know that the Earth revolves around the Sun. The time it takes Earth to make one revolution, known as
a year, takes exactly 365 days, 5 hours, 48 minutes, and 46 seconds. People in ancient times did not even know
that the Earth was circling the Sun, however, let alone how long it took. What they did know was that every 29½
days, the moon passed through a cycle in which it changed shape. Early civilizations like the Babylonians,
therefore, designed calendars based on the moon.
3. There was just one problem with this system. Twelve moon cycles add up to only 354 days. A calendar based on
the moon would work fine for the first few years, but eventually it would get out of step with the changing
seasons. To correct this problem, ancient kings often randomly inserted an extra handful of days or even an extra
month into certain years. As you can imagine, this caused a lot of confusion!
4. The Roman calendar is a good example of how early calendars failed to match the changing seasons. It had ten
months, or 304 days. The Romans seem not to have worried too much about the extra 61 days, until a Roman
ruler named Numa Pompilius added the months of January and February. This made the Roman year 355 days
long. Numa also ordered that a month called Mercedinus be inserted into the calendar every other year.
5. By the time of Julius Caesar, the Roman calendar was about three months ahead of the seasons. Winter officially
began in September, and fall started in July. In 46 B.C. Caesar asked an astronomer named Sosigenes to make the
calendar more accurate. The result was that Caesar ended up making the year 12 months long. Each month had
either 30 or 31 days, except for February, which had 29 days. In order to catch up with the seasons, Caesar
ordered that the year 46 B.C. would have 445 days.
6. The Romans called 46 B.C. “the year of confusion.” However, they showed that they appreciated Caesar’s efforts
by renaming the month they called Quintilis in his honor, calling it “July” for Julius. The month after July, which
had been known as Sextilis, was later changed to August to honor the Emperor Augustus Caesar. According to
legend, Augustus was unhappy that July had 31 days while his month, August, had only 30 days. So he moved a
day from February to make August as long as July.
7. The calendar that Caesar had designed was called the Julian calendar. It was used in many places for more than
1,500 years. However, the Julian year of 365¼ days was 11 minutes and 14 seconds longer than the time it
actually took Earth to circle the Sun. By the year 1580, these minutes had added up to ten days, once again
making the calendar slightly out of step with the seasons.
8. In 1582 Pope Gregory XIII established the Gregorian calendar to correct the mistakes caused by the Julian
calendar. He dropped ten days from October that year and ordered that every fourth year February would have an
extra day.
9. The Gregorian calendar matches the solar year very accurately. It is just 26.3 seconds longer than the time it takes
Earth to circle the Sun. Those 26.3 extra seconds each year will eventually build into days that will throw the
calendar off. Still, it is our best bet until someone invents a calendar that is exactly the length of the solar year.

2. Liang and Bao
1. Liang was standing in the hallway when she saw her younger brother, Bao, coming out of the earth science
classroom. He didn’t see her at first, and when he did, he looked embarrassed that she knew that he had stayed
late to get extra help. Although they rarely talked about it, Liang knew Bao was having trouble understanding
earth science, and the final was in a few days. Liang also knew how much it meant to him to do well on the test,
but science was difficult for Bao.
2. Liang thought about her brother a lot. He was good at English and especially at writing. He loved to write stories
about things that were happening and then have them printed in the school newspaper. He was the youngest
person on the newspaper staff, and that was quite an honor. No one was sure why Bao was so talented in
English—certainly his mother and father had no idea—but for as long as he could remember, he wanted to be a
journalist. He hoped someday to be a foreign correspondent, traveling to faraway places and covering exciting
stories. Liang remembered Bao as a child frequently reading and writing things, even before she was interested in
doing so.
3. But now, Liang was worried about Bao and how he was doing in earth science. She had never had a problem with
any kind of science course. She excelled at chemistry, which she was taking this term, and hoped one day to be a
science teacher. She was three years older than Bao, and she felt much more secure than he did because she had
more experience. She had had her problems in school but worked hard and mastered difficult subjects like
English. While writing was second nature to Bao, Liang had to work hard at it, but she was able, through revising
and revising, to create a thoughtful and sound paper when she needed to do so.
4. Even though they sometimes disagreed about things, Liang and Bao were very close. They enjoyed the same
movies and music, and they were both excellent runners. But there was something that kept Bao from feeling
comfortable about asking his sister for help. He was very proud, and he felt he should be able to do everything on
his own, just like Liang.
5. Liang was sure that if she helped him review the material, he would be able to master it. She knew she was a
teacher at heart, and she felt frustrated that he didn’t want her to help him in spite of the many times she offered.
She decided that she had to figure out a way to make Bao want her to help him. Later that day, Liang and Bao
were walking home together, and Liang decided to approach her brother in a new way.
6. “Bao, I have a paper due by the end of the week, and I wondered if you could take a look at what I’ve written so
far and give me some advice.”
7. Bao was surprised because he had never heard his sister ask him for help at doing anything—more often she was
asking him if he needed help. He had always thought that Liang was independent and able to do anything she
wanted. Bao was pleased that she would call on him since it made him feel important, a new role for him.
8. “Sure, I’ll look at what you have done so far when we get home. What’s your topic?” he asked.
9. “It’s a report on Herman Melville, the American writer,” she answered, “You know he wrote Moby Dick, about
the search for the white whale.”
10. Moby Dick was one of Bao’s favorite novels, and Liang knew that. She also knew that Bao knew a lot about
Herman Melville, so she thought he might like the opportunity to help Liang with her paper. She was right. Bao
said he would read through her first draft when they got home. He was excited by the prospect of Liang needing
his help.
11. Later he read Liang’s draft and realized that it was very good, but he thought he should make some
recommendations anyway. He asked himself why his sister would ask for help when she didn’t really need any.
12. Bao found Liang in the kitchen, reading a book. He turned to her and said, “I think your paper is very good, but if
you made an outline of what you want to say, and then make some other little changes, it would be even better.”
Bao started to bubble over with other kinds of suggestions, and then he stopped and looked more closely at what
Liang was reading. “I’ve always loved earth science,” Liang said to Bao. “I just wanted to review some of the
material—I’ve forgotten a lot since I took it in my freshman year, and if I want to be a science teacher, I should
keep reviewing all aspects of science.”
13. Bao smiled to himself as he began to realize what Liang was trying to do. His sister’s motives were a bit
transparent, but he thought, if she wants to help me that much, I guess I should let her.
14. “Would you mind if I reviewed the material with you too? I’m a little confused about some of the things that we
are required to know,” he asked his sister, who smiled and nodded yes.
15. “Pull up a chair,” she said.
16. Several days later, the final exam was over, and Bao was pleased with his grade. He went to his sister and thanked
her. “You went to a lot of trouble for me.
Thanks. It means a lot,” he told her.