## Celebrate Leap Day – The FUN Science of Telling Time!

Thirty days hath September…but why on earth does February have 29 every four years?

This year is a leap year, making the length of the 2012 calendar 366 days, instead of the normal 365.  Every four years an extra day is added to the month of February, but have you ever wondered why this happens?  In celebration of 2012 being a Leap Year, we invite you to hop back in time with us for a brief history of our modern day calendar and discover the FUN science of telling time!

The calendar is supposed to match the solar year, in other words, the length of time it takes for the Earth to orbit the Sun once. But things aren’t quite that simple. It actually takes Earth 365 days, 5 hours, 48 minutes and 46 seconds to complete its orbit (about 365 1/4 days). Those extra hours gradually add up so that after four years the calendar is out of step by about one day.  Adding a day every four years allows for the calendar to match up with the solar year again.

However, because the solar year isn’t exactly 365 days, even adding a leap day every four years means that the calendar is still out of step by 11 minutes and 14 seconds each year. Over the course of 400 years this would add up to three extra days. In order to solve this problem it was decided to leave out the leap year three times every 400 years. So the new rule was, a century year (1600, 1700, 1800, etc..) would only be a leap year if it was evenly divisible by 400.  This means that the year 2000 was a leap year, but 2100 will not be.

Phew! So, who figured all this out?

The Egyptians were the first people to think of adding a leap day to the calendar. Later, the Romans copied the idea and in 1582 Pope Gregory XIII reformed the Julian Calendar (introduced by Julius Caesar in 45 BCE). By Pope Gregory’s time, the calendar had drifted 14 days off track. He neatly solved this by wiping ten days off the calendar, telling everyone that the day after October 4th was going to be October 15th. Bad luck for people with birthdays during that time, including famous scientist Sir Isaac Newton. His birthday according to the Julian calendar, used during the year of his birth, was Christmas Day, 1642. However, once the Gregorian Calendar went into effect,Newton’s birthday changed to January 4th, 1643.

The early roman calendar originally began the year in the month of March. It consisted of ten months, each lasting about 30 days, ending with December. This ten month calendar completely left out the winter months.  It is thought that the two extra months, January & February, were added sometime around 715-673 BCE. This would have made February the last month of the year, which might explain why a leap day was added to that month. Later, it was decided to start the year with January.

Other nations have different leap year rules and different methods of keeping their calendar in line with the solar year.  Countries may have a day, or in some cases a month, that gets added every few years in order to balance the time. The Chinese, for example, add a month about every three years, whereas in the Islamic Hijri Calendar a day is added 11 times during a 30-year cycle.

It can be pretty confusing keeping track of our modern day calendar, but just remember…

Thirty days hath September,

April, June and November;

All the rest have thirty-one

Save February, she’s alone

Hath eight days and a score

Til leap year gives her one day more!

Did You Know?

There is a tradition that women are allowed to propose marriage to men on leap days! One day in the 5th century, St. Bridget complained to St. Patrick about the unfairness of the system which only allowed men to propose, so he decided to let women do the asking once every four years!  Today, we refer to this special day as Sadie Hawkins Day!

FUN BrainPOP Video about leap year

Leap Year 2012

Take The Leap: FUN Leap Year Quiz!

Happy Leap Day!

## Happy Birthday Benjamin Franklin!

The Lightning Rod

When most of us think about Benjamin Franklin and his inventions, we think about a man running around outside during a thunderstorm with a kite. Ask any child and they will be quick to tell you that Benjamin Franklin invented electricity but the fact of the matter is, Franklin didn’t invent electricity, he simply figured out how the transfer of electricity works by inventing the lightening rod. During that time, in the 1700s, fires were commonplace as a result of lightning strikes. His simple lightning rod helped to channel that power away from the houses and buildings, and to a grounded source.

Bifocals

Were you aware that Ben Franklin also invented bifocals? As Franklin got older, he realized that his vision had started to decline. The inventor turned to science to find a solution for the uncomfortable task of switching between glasses for close-up reading and distance viewing. In 1784, Franklin discovered his solution with a pair of engineered eyeglasses he dubbed “double spectacles. Franklin had his optician take the lenses from his two sets of glasses, cut the lenses in two horizontally, and then mount them back into the frames. The optician placed the lens for close work at the bottom and the lens for distance at the top. Traditional eyeglasses simply correct vision for one distance, but the invention of the bifocal allowed for two corrective powers to be used in each lens, thus eliminating the need to switch between.

Odometer

Benjamin Franklin did not always work as an inventor. As a matter of fact, he once served as the postmaster general. In an effort to figure out the best route for delivering mail, he invented a simple odometer which allowed measurements between two areas when it was attached to the delivery carriage. Today, the odometers used in automobiles are much more complex.

The Gulf Stream

Did you know that Ben Franklin was the first scientist to study the Gulf stream? The Gulf stream is a powerful, warm current in theAtlantic Ocean. Those of us who live along the coast are familiar with what the Gulf stream is but very few of us realize the fact that Benjamin Franklin is one of the men that helped map it out. It was known that sailing from the United  States to Europe took less time than traveling in the other direction. This fact fascinated Benjamin Franklin so he took the time to map out the Gulf stream by measuring current depths and wind speed in order to come up with one of the first, accurate concept drawings of the phenomenon.

The Franklin Stove

The Franklin stove was a concept that was thought up by Benjamin Franklin in order to help individuals use less wood, while still producing more heat. Since wood fires accounted for a lot of the heat during that time, having a more efficient way of receiving that heat was welcomed by almost everyone. Something that is interesting about this particular invention is the fact that he turned down a patent for this concept. He wanted it to be available for everybody and was not interested in making a profit from it.

Today, young scientists are looking to the stories of Franklin’s experiments and his inventions and finding their own scientific inspiration. The Franklin Institute is a great resource for information on Benjamin Franklin. You can visit this website to find instructions for experiments with electricity, air, heat, and even the Glass Armonica. Find your own inspiratin and spark your imagination with even more experiments including how to build your own Leyden Jar!