Posted on 1 Comment

The Astronomy of Easter

He is not here: for He is risen! – Matthew 28:6

Every Christian knows that Jesus was crucified in Jerusalem at the time of the Passover, and in this way became the perfect Passover sacrifice, “the Lamb of God which taketh away the sin of the world” (John 1:29). Since the early centuries of the church, Christians have honored the death and resurrection of Jesus in the celebration of Easter. And while the observance of Easter has changed over the centuries, it is based on the Hebrew Passover.

Hebrew Roots

We read in the Book of Exodus how the LORD used Moses lead the Israelites out of Egypt. In Exodus 12, the LORD sent the final plague, smiting the firstborn of all Egypt. The Israelites were saved by sacrificing a lamb and covering their doorframes with its blood, so that the LORD would “pass over” the house and not smite the firstborn of Israel. And the LORD commanded that the Israelites remember the Passover in a seven day feast….

And this day shall be unto you a memorial; and ye shall keep it a feast to the LORD throughout your generations; ye shall keep it a feast by an ordinance for ever. – Exodus 12:14.

The LORD instructed Israel as to when the Passover should be kept:

In the first month, on the fourteenth day of the month at even, ye shall eat unleavened bread, until the one and twentieth day of the month at even. – Exodus 12:18.

In the lunar calendar, the New Moon is the first day of the new month. The Full Moon is at mid-month, the fourteenth day of the month. So Israel was instructed to celebrate the Passover on the Full Moon of the first month. The LORD even tells us the name of the month….

Observe the month of Abib, and keep the passover unto the LORD thy God: for in the month of Abib the LORD thy God brought thee forth out of Egypt by night. – Deuteronomy 16:1

The word “Abib” means “sprouting” or “budding” and is the first month of Spring, falling among our months of March and April. Abib is the only month of the year named by God in the books of Moses.

The Bible doesn’t clearly indicate the calendar method used to keep track of Passover and other Hebrew holidays. However, for centuries the Jewish calendar has been based on the well-known 19 year cycle of the Sun and Moon. God in His providence established that 235 cycles of the Moon’s phases is nearly equal to 19 solar years. This means that every 19 years, the Moon’s phases will recur on the same dates of the solar year.

This 19 year “luni-solar” cycle was the basis for the calendar used in Babylon. In the west, its discovery is attributed to the Greek philosopher Meton, who may have learned it from the Babylonians. The 19 year cycle was generally well known and understood in antiquity, and was apparently used by the Persian rulers of Babylon after the restoration of Israel.

It appears that the modern Jewish calendar was directly influenced by the Babylonian calendar. In addition to using the 19 year cycle, the modern Jewish calendar uses months with names nearly identical to the Babylonian names. In the books of Nehemia, Ezra and Esther (which record events after the Babylonian exile) you can find the month names “Sivan,” “Elui,” and “Adar,” nearly the same as their Babylonian counterparts.

Most notable is the month “Nisan,” the first month of Spring, corresponding to the Mosaic month of “Abib.” In the modern Jewish calendar, Passover occurs on the fourteenth day of Nisan. The Jewish historian Flavius Josephus, writing in about 90 A.D., gives us an astronomical reference for the month of Nisan….

In the month of Xanthicus, which is by us called “Nisan,” and is the beginning of our year, on the fourteenth day of the lunar month, when the Sun is in Aries (for in this month it was that we were delivered from bondage under the Egyptians, the law ordained that we should every year slay the sacrific which I before told you we slew when we came out of Egypt, and which was called the Passover;….)

In the time of Josephus, the Sun was in the constellation Aries at the time of the Vernal Equinox, the first day of Spring in the northern hemisphere. And so in the traditional Jewish observance, the Passover feast begins with the Full Moon during the month of the Equinox.

What’s in a Name?

The early church celebrated Passover in a similar manner to Jewish observances, though the customs changed over time. But our Christian Easter observance is still based on the Hebrew passover observance. For example, many churches observe the solemn, penitent “Holy Week” observance before Easter, based on the seven-day Feast of Unleavened Bread.

Many people today argue that “Easter” is really a pagan holiday, with bunnies and eggs symbolizing heathen fertility rites, not the resurrection of Jesus. Entire books have been written to show that the name “Easter” is derived from the name of the Babylonian fertility goddess “Ishtar” or “Astarte.” Eggs and bunnies are clearly not of Biblical origin. But the name issue is mostly a matter of the semantics of the English language since other European languages paint a different picture.

The Hebrew word for “Passover” is “pesach.” In Greek, the translated word is “pascha.” Throughout church history, this name has been associated with the feast of Christ’s resurrection. This name of this feast is translated in the following ways in the languages of the traditionally Christian nations of Europe:

Spanish = Pascua

Italian = Pasqua

French = Paque

Russian = Pascha

Swedish = Pask

Norwegian = Paske

Dutch = Pasen

However, in the English language, the feast of Christ’s resurrection is commonly called “Easter.” For example, in Acts 12:4 in the King James Bible, the word “Easter” is given as a translation of the word “pascha.” If you read old-fashioned English writings, it’s not uncommon to see the Easter feast called “The Pasch” (pronounced “pask”) and Jesus often figuratively referred to as “the paschal lamb” and so forth. However, the word “Pasch” is out of style in our shallow generation of English speakers.

It appears that the word “Easter” is derived from the name of an old Anglo-Saxon fertility goddess associated with the east, who had a springtime festival. The German word is “Ostern,” and since the Anglo-Saxons were originally a Germanic tribe, it’s pretty clear that the words are related. While old habits apparently die hard in the English and German languages, it’s pretty clear that most traditionally Christian nations name the Pasch as the proper name of the feast of Christ’s resurrection.

The Reckoning of the Pasch

In the early days of the church, Christians kept the Pasch in the same manner as the Jews, beginning on the 14th of Nisan. But as time went by, Christianity developed distinctive observances that differed from Jewish practices.

In the church at Rome, it became customary to celebrate the Pasch on the Sunday following 14 Nisan, in order to commemorate Jesus’s rising on the first day of the week. This became a controversy in the late Second Century. Victor I, the bishop of Rome, argued that the churches of Asia Minor should follow the Roman practice, rather than celebrate the Passover on 14 Nisan in the Jewish manner.

Since the early centuries, the Christian churches used the official Julian civil calendar of Rome to calculate the date of the Pasch. Since it was not always easy to know the date of the Equinox, calendar tables were prepared years in advance. The Roman method of calculating is explained here by the English scholar, the Venerable Bede, who wrote a definitive work on the subject around 700 A.D.:

The beginning of this month ought to be observed according to this rule: so that the fourteenth Moon of Easter never precedes the vernal equinox, but correctly appears either on the equinox itself (that is March 21) or after it has passed.

In the early centuries, during persecution by the Roman Empire, Christianity was a loose collection of local churches each led by an independent bishop. Since there was no central authority, not every local church agreed with the Roman method. For centuries, the various churches squabbled about the correct time for celebrating the Pasch.

A concord was finally established at the Council of Nicaea in 325 A.D. The Council of Nicaea is best known for establishing and affirming the doctrine of the Trinity. Other proclamations were made, including the method of calculating the date of Easter. The synodical letter of the Nicene council reported….

We further proclaim to you the good news of the agreement concerning the holy Easter…. all our brethren in the east who formerly followed the custom of the Jews are henceforth to celebrate the said most sacred feast of Easter at the same time as the Romans….

The council emphasized that Easter should never occur during the Passover, due to antagonisms toward the Jewish people and some apparent inconsistencies in the Jewish calendar.

In this way, the Council of Nicaea established a common celebration of the Pasch. In the centuries following Nicaea, the church became increasingly uniform in other doctrines and practices, and centralized in authority. Nevertheless, the issue of Easter had come up again and again throughout church history, and there remain differences to this day.

A Slight Problem

As established by Julius Caesar, the solar year was reckoned as 365 days with an extra day added during a “leap year” every four years. In this way, the natural period of the seasonal year was understood to be 365 1/4 days in length. As explained by the Venerable Bede….

The Sun’s year is complete when it returns to the same place with respect to the fixed stars after 365 days and 6 hours, that is a quarter of a whole day.

By this reckoning, the time from one Vernal Equinox to the next should have been 365 days, 6 hours. However, it was not known to either Julius Caesar or the Venerable Bede that in fact the solar year was precisely 365 days, 5 hours, 48 minutes and 42 seconds. As a result, the time from one Vernal Equinox to the next was overestimated by 11 minutes and 18 seconds.

We might be tempted to say that this is a tiny amount, what difference can 11 minutes make over the span of a year? Very little difference, but over a century of time, it can add up. This minor annual discrepancy amounts up to about three extra days every 400 years. And over many centuries, the accumulated days became considerable.

In the time of Caesar, the Vernal Equinox occurred on March 24. By the time of the Council of Nicaea, the Equinox was arriving on March 21. Throughout the Medieval period, the Equinox was arriving earlier and earlier. Consequently, the date of Easter was arriving earlier and earlier. Given enough centuries, Easter would regress backward through the calendar and begin to approach Christmas!

By the 1500s the Julian calendar had slipped 10 days from the Council of Nicaea, and the Equinox was arriving on March 11. Calendar reform became a topic for discussion among church authorities, in part because the nature of the problem was poorly understood. The revolutionary work of Mikolaj Kopernik (a.k.a. “Copernicus”) was inspired by the effort to reform the calendar. In 1543 he wrote….

When the Lateran Council was considering the question of reforming the Ecclesiastical Calendar, no decision was reached, for the sole reason that the magnitude of the year and the months and the movements of Sun and Moon had not yet been measured with sufficient accuracy.

(Of course, Kopernik’s solution included the novel idea of placing the Earth in orbit around the Sun, but that’s another story.)

The final solution was adopted 40 years later, in 1582. Upon consulting with the learned astronomers of the time, Pope Gregory XIII issued a proclamation that restored the calendar….

So thus that the Vernal Equinox, which was fixed by the fathers of the Nicene Council at March 21, is replaced on this date, we prescribe and order that there is removed, from October of the year 1582, the ten days which go from the 5th through the 14th inclusively. The day which follows the 4th, when one traditionally celebrates St. Francis of Assisi, shall be the 15th.

In this way, the Equinox once again arrived on March 21, as it had in 325 A.D. To accommodate future drift in the calendar, Gregory made the following provision….

Then, lest the Equinox recede from March 21 in the future, we establish that a bissextile (a.k.a. “leap year”) shall be inserted every four years (as with the present custom), except in centennial years…. Thus, the years 1700, 1800 and 1900 will not be bissextile, and then, as with the habit with which we are accustomed, the year 2000 will have a bissextile intercalation day, as the day February 29, and that the same order of intermittent intercalations in each four hundred year period will be preserved in perpetuity.

And so Gregory established that three out of four centennial years would not be leap years, so as to drop three days from every 400 years, and thus maintain the predictable order of Easter and the seasons. Remarkably, Gregory looked ahead from the Middle Ages to our lifetimes to establish that the year 2000 would be the first centennial leap year in 400 years. Sadly, our generation is so ignorant of classical astronomy that February 29, 2000 came and went with little or no notice, in the media or otherwise.

Gradual Acceptance

The reformed Gregorian Calendar was immediately adopted in October, 1582 throughout the Roman Catholic nations of Europe. But the Protestant and Eastern Orthodox nations resisted this “popish innovation.” One early Protestant proponent of the new calendar was the astronomer Johannes Kepler. In 1597, he argued with his superiors that it was “small-minded to demonstrate Protestant independence of thought by protesting against a most useful reform introduced by the Catholic Church.”

For a century and a half thereafter, the nations of Europe maintained an awkward system of keeping two dates for every notable event, one in the “Old Style” of the Julian Calendar, and another in the “New Style” of the Gregorian Calendar. For example, one might notice that George Washington’s birthday is sometimes given as “February 11, 1732 O.S., February 22, 1732 N.S.”

Over time, the Protestant nations gradually accepted the Gregorian Calendar. In 1752, England finally adopted the New Style, and its American colonies followed at the same time. Here’s how it was reported in “Poor Richard’s Almanack” by “Richard Saunders,” a.k.a. Benjamin Franklin….

…the King and Parliament have thought fit to alter our Year, by taking eleven days out of September, 1752, and directing us to begin our Account for the future on the first of January…. wishing withal, according to ancient Custom, that this New Year (which is indeed a New Year, such an one as we never saw before, and shall never see again) may be a happy Year to all my kind Readers.

Nowadays, the Gregorian Calendar has become the civil calendar that regulates the affairs of the entire secular world, including nations far and wide that have no historical Christian roots.

The Eastern Orthodox church still retains the Julian Calendar for regulating its church calendar. By the 21st century, the seasons have slipped 13 days from the time of Nicaea. So the Vernal Equinox is now arriving on March 8, O.S. The Eastern church celebrates Christmas on December 25 as reckoned by the Julian Calendar, which is January 7 on the Gregorian Calendar.

One principle objection of the Eastern Orthodox church is that the Gregorian Calendar did not reiterate the Nicene prohibition against celebrating Easter after the Jewish Passover. As a matter of fact, we can witness this now in the year 2003. This month, Passover is on April 17, and the Gregorian Easter in on April 20. However, the Orthodox Easter is one week later, on April 27, in accordance with the decree of Nicaea.

So ironically, 1700 years after the Council of Nicaea established a common celebration of Easter, there is still disagreement over this very issue.


Jay Ryan is the author of Signs & Seasons, an illustrated, Biblically-centered homeschool curriculum for Classical Astronomy. He is also the creator of the Classical Astronomy Update, an email astronomy newseltter especially for Christian homeschoolers.  Visit his website at ClassicalAstronomy.com.

Source: http://www.homeschool-articles.com/the-astronomy-of-easter/

Posted on 3 Comments

Learning Simple Machines: 4 Tricks to Help Your Children

What exactly are simple machines? How do they work? And how do you make learning simple machines easy for your children? Learning simple machines can be accomplished by using common examples to help your child comprehend these basic scientific concepts. Hand tools, silverware, even parts of the human body can all be considered simple physical machines.

Any physical machine makes work easier to accomplish. To a scientist, work is the amount of force (a push or a pull) used along the distance upon which the force acts, or the product of force and distance. For work to be done in a scientific sense, the object must move in the same direction in which the force acts. As you carry a heavy stack of books across the room, you do not do work on the books, since motion and force act in different directions. The motion is in the horizontal direction, along the floor, while the force is straight up, acting against the weight of the books. When you lift the stack of books straight up, you do work on the books, since the applied force and the direction of motion are the same. If you carry the books up or down a flight of stairs, then you do work on the books along the height of the stairs.

Simple, physical machines make work easier by multiplying either the force on the object or the distance involved. A see saw does work on the people sitting on either end. Have you ever changed your position on one end of a see saw to allow a small child sitting on the other end to go up and down? You adjusted one part of a lever to allow it to do work, that is, to lift up the people on each side easier. Learning simple machines is as easy as you and your child experimenting with this concept using a ruler, a pencil, and a few coins. Place the ruler across the pencil at a right angle to the pencil and at the middle of the ruler. Place one coin after another on alternating ends of the ruler and at different distances from the pencil until the ruler balances on the pencil. What do you notice about the types of coins you use? How far away are the coins from the pencil? How many coins do you place on each side of the ruler?

Depending upon your reference, simple machines can be classified into many categories, but the two basic groupings are levers and inclined planes. A lever has two sections, or lever arms, which move around a fixed point called a fulcrum. Levers may include an automobile jack, wheelbarrow, see saw, broom, shovel, or a human’s forearm. An Inclined plane is a ramp or slanted surface along which a force moves an object to different elevations. Two inclined planes placed back to back, form a wedge that is used to split things apart. Inclined planes include staircases, screws, mountain roads, and a human’s front teeth.

Most ordinary hand tools are composed of simple, physical machines. A pen or a pencil is a lever. A door knob that turns is a lever, both for pulling or pushing the door and the door knob itself. A nut cracker is a lever. A wall light switch is a lever. A crowbar is a lever. The length of a nail is a lever, while its pointed tip is an inclined plane. The length of a table knife is a lever and its blade is an inclined plane. A fork is a lever and so is a spoon. The tines on most forks end in points, therefore they are inclined planes. A hand-operated pencil sharpener is a combination of levers and inclined planes. Examine a pair of scissors closely. Can you find these simple machines? The lengths of the blades and handles are levers. The tiny post the levers turn around is a wheel and axel and also a lever. The blades are inclined planes. One edge of each blade is narrower than the other, forming a miniature ramp. By identifying these common items children are learning simple machines without even realizing it.

You can use every day examples to aid your children in learning simple machines. They can help explain what simple machines are and how they function. With practice children can distinguish physical objects as simple machines and determine how they operate. Simple physical machines can be located in the kitchen, in the garage, in the toolbox, and even in the human body.


Lorie Moffat has 20 years of teaching experience in both public school classroom and science museum settings. Contact her about special summer online tutoring packages.

Source: http://www.homeschool-articles.com/learning-simple-machines-4-tricks-to-help-your-children/

Posted on

Teaching Children about the Four Kinds of Kinetic Energy

Your child comes home with questions about the different kinds of kinetic energy. So how do you distinguish between the many different types? You can use common examples to help your child understand the kinds of kinetic energy.

Kinetic energy, or the energy of motion, is the ability to do work. If you use a force across a distance, you do work in a scientific sense. If you slide a book across a table, you have used kinetic energy. The many kinds of kinetic energy include mechanical, electrical, radiant, and sound.

Four Kinds of Kinetic Energy #1- Mechanical kinetic energy is the most familiar and common example of kinetic energy. As an object moves, it has kinetic energy. In order to lift an orange over your head it takes a joule of work. Kinetic energy is measured in joules (rhymes with cool) or Newton-meters, with force measured in Newtons and distance measured in meters. A car accelerating at the same rate as a bicycle has more kinetic energy because it has more mass.

Four Kinds of Kinetic Energy #2– Electrical energy that moves through wires is measured in watts. A joule of work done in one second is a watt, which is named for James Watt, the inventor of the steam engine. Trains used to run using steam engines. If you lift a quarter-pound hamburger with cheese vertically, a distance of one meter in one second, you use a watt of power. Take a close look at a light bulb that is not in a lamp. You will see a number followed by “kw”, or kilowatts, on most light bulbs. Electric motors also have kilowatt ratings. A kilowatt is one thousand watts. Electrical power can also be described as the product of current, measured in amperes or amps, and potential, measured in volts.

Four Kinds of Kinetic Energy #3- Solar energy is the heat and light, or radiant energy produced by the sun. The sun does not burn like a fire does. Nuclear fusion creates the sun’s energy. Helium atoms are formed from lighter hydrogen atoms, in the process creating heat, light, and other particles.

Light energy is a form of radiant energy emitted by accelerating electric charges or the electrons of atoms. Light we see, or visible light, is a small portion of electromagnetic waves, which are partly electric and partly magnetic. Light moves through the vacuum of space or through a material as waves. A wave can be described as a back and forth motion or a vibration.

Light can also move as particles, or photons. Frequency measures how many complete vibrations occur in a given time period, usually a second. Hertz is the unit for frequency, named from Heinrick Hertz who demonstrated radio waves, a type of electromagnetic radiation in 1886. Electromagnetic waves range from the longest, radio waves, to the shortest, gamma rays. The lowest frequency of light that we can see is red and the highest is violet. AM radio waves are broadcast in thousands of hertz, or kilohertz. FM radio waves are broadcast in millions of hertz, or megahertz. Radar and microwave ovens operate in the gigahertz, or billions of hertz range. X-rays and even shorter gamma rays are used in chemotherapy. In a vacuum, all electromagnetic waves travel at the speed of light which is 300,000 km/s.

Heat energy is another form of radiant energy. If you have ever seen a shimmering effect above a paved road or parking lot on a hot day, you have seen heat waves. You can feel heat radiating from a candle flame, a fireplace, or a space heater. Most light bulbs heat up while they operate because the tiny wire inside each bulb, called the filament, heats up and glows.

Four Kinds of Kinetic Energy #4- Acoustic, or sound, energy begins with the vibration of an object. A guitar has strings that vibrate to produce sound. A clarinet has a vibrating reed while a trumpet has a vibrating column of air in the mouthpiece. The human voice has vocal chords. These vibrations start waves in the air. However, sound also needs something to move through, or a medium. There is no sound in outer space since there is nothing for it to travel through. Astronauts outside the space shuttle or the International Space Station use radio waves, a form of electromagnetic radiation, to communicate.

You can use common examples to explain the various kinds of kinetic energy to your child. The many forms of kinetic energy include mechanical, electrical, radiant (heat and light), and sound.


Lorie Moffat has 20 years of teaching experience in both public school classroom and science museum settings. Contact her about special summer online tutoring packages.

Source: http://www.homeschool-articles.com/teaching-children-about-the-four-kinds-of-kinetic-energy/