(peppy music) (upbeat music) Hi.

I'm Courtney Cochran, and I would like to read the book Clang Ernst Chladni's Sound Experiments.

This book is written by Darcy Pattison and illustrated by Peter Willis.

In the year 1806 Ernst Florens Frieddrich Chladni locked the door of his house in Wittenberg, Germany, climbed into his spacious carriage and left town.

It would be four years before he returned.

Chladni was a scientist who studied sound.

Unlike many scientists at the time, Chladni didn't work for a university.

Instead, he traveled because he earned money by entertaining people with his sound experiments.

Chladni traveled in the Netherlands and Brussels for two years.

In 1808, Chladni moved on to Paris, France There he met with French scientists who admired his work.

The French scientists especially liked his 1802 book, Die Akustik, or The Acoustics.

The book explained the science of sound and sound waves.

However, the book was written and Chladni's native German language.

French scientists encouraged Chladni to translate the book into French.

But Chladni had two problems.

First, he needed enough money to live on while he did his work.

Second, he needed someone to make sure his French was correct.

Chladni's friends, the French scientists decided to help with both problems.

At 7 p.m. on a Tuesday evening in February 1809, a carriage pulled up to the Tuilerie Palace in Paris, France.

This was home of the notorious Napoleon Bonaparte, Emperor of the French people.

Perhaps Emperor Bonaparte would help fund Chladni's book.

When Chladni entered, Napoleon welcomed him.

He introduced Chladni to his wife, his mother, his uncle and his assistant.

Quickly, Chladni set up his equipment.

First, he entertained them by playing the clavicylinder, a musical instrument he had invented.

It looked something like a piano, but pianos create sound by hitting wires of different lengths.

Instead, the clavicylinder made a sound by rotating a glass cylinder.

When he pushed a key on the keyboard, a bar moved forward to touch the cylinder.

The bar vibrated and made a sound.

Chladni played some musical pieces on the clavicylinder.

It pleased everyone.

Napoleon asked if he could play the clavicylinder.

Chladni agreed, but he suggested that it should be played softly because of the glass cylinder.

Instead, Napoleon banged to the keyboard!

Fortunately, the clavicylinder didn't break.

Napoleon whispered to one of the French scientists, Could I see the inside of the clavicylinder?

Chladni overheard the Emperor's question.

He answered, The instrument is still a secret.

He wouldn't allow anyone to look inside because he was afraid someone might steal his invention.

Next, Chladni planned to demonstrate sound experiments.

Sound waves are hard to study because they can't be seen.

Early in his career, Chladni studied how sound was created by vibrating strings of a musical instrument.

Next, he studied how fast sound waves moved through the air of a pipe organ.

His most famous experiments, though, were how sound traveled through solids, such as metals or glass.

Chladni started his sound experiment for the Emperor by centering a brass plate onto a single support.

Sand was sprinkled over the plate's surfac He used a violin bow to stroke the side of the brass plate.

As the sound wave traveled through the plate, it made the brass vibrate.

The vibrations pushed the sand around.

Sand gathered in places where the brass plate was not vibrating.

Very low sounds made simple shapes.

Very high sounds made complex shapes.

The audience was fascinated by the sound wave figures in the sand.

Napoleon knew that mathematics can explain science.

He asked Chladni to explain the mathematics of how sound waves travel through solids.

While Chladni understood some of it, he didn't have the full mathematical explanation.

The next morning, Napoleon sent Chladni a gift of 6000 francs to translate his book into French.

It was enough for Chladni to live comfortably for several years while he worked on the French version of his book.

The French language was difficult for Chladni to write about sound.

For example in German, he could write schall (ring out or peal), klang (clang or clink) and ton (resound).

But French only had one word for sound, son.

French scientists helped Chladni with the language.

His new book, Traite d'acoustique, or Treatment of Acoustics, was published in French in November, 1809.

In the opening, Clhladni, he wrote this dedication: Napoleon, the Great deigned to accept the dedication of this work after having seen its fundamental experiments.

Science historians say Chladni's book was revolutionary.

It created a new field of scientific study the study of sound or acoustics.

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