Hat on or off? Right or left hand? What if it gets dirty? These are some typical questions people have about customs and rules surrounding the American flag. No worries. In honor of the 200th anniversary of "The Star-Spangled Banner", the song that became our national anthem, intern Talia Berday-Sacks shares some pointers about proper flag etiquette with objects from our collections.

First off: are there any official flag rules?

Yes and no. The U.S. Flag Code is a set of rules (not a law) for civilian flag use that was published on June 14, 1923, (Flag Day!) and adopted by Congress in 1942. The U.S. Flag Code set forth prohibitions on what were deemed disrespectful uses of the flag and included official rules on proper conduct during flag ceremonies, flag display, and flag maintenance.

Patriots Text Book. In the 1920s, when the U.S. Flag Code was created, teaching respect for the flag was considered an essential part of "Americanization," the process of assimilating immigrants into loyal, English-speaking citizens.

Disrespecting and desecrating the flag used to be a federal crime, but with the 1989 case of Texas v. Johnson, the U.S. Supreme Court ruled that flag anti-desecration laws violated the First Amendment right to freedom of speech. Today, the U.S. Flag Code is purely advisory. This explains why companies today can legally use images of the flag to advertise their products. Even without official flag rules, people still believe in treating the American flag with great respect and honor.

Cigar box label: Some of the earliest court battles over flag desecration focused on tobacco and alcohol advertisements, which were criticized for linking the flag to immoral habits.

In this 1911 postcard created by the National American Woman Suffrage Association, the stars on the flag represent states that have voted for suffrage. Throughout American history, many interest groups have used flag imagery to promote their cause.

Guidelines for flag etiquette

The salute: World War II changed how Americans saluted the flag during the recitation of the Pledge of Allegiance. Children used to be taught to salute their right hand to the forehead and then to extend the right hand out toward the flag. Because this salute closely resembled the Nazi one-armed salute, this American salute was replaced in 1942. Now the custom is to put the right hand over the heart.

Image of soldier saluting the flag. Note the forehead salute. Pete Claussen Collection of American Flag Magazine Covers, Archives Center, National Museum of American History.

In rain or shine: According to the U.S. Flag Code, "The flag should not be displayed on days when the weather is inclement, except when an all-weather flag is displayed." Since so many flags today are made of synthetic materials like nylon, the flag can be displayed in practically any weather without fear of damage.

Day or night: Although it is customary to display the flag from sunrise to sunset, the U.S. Flag Code mentions that the flag can be displayed 24 hours a day "if properly illuminated during the hours of darkness."

Laws and presidential proclamations have authorized the constant flying of the flag at the U.S. Capitol Building; the White House; the U.S. Marine Corps War Memorial in Arlington, Virginia; Baltimore's Flag House Square and Fort McHenry National Monument and Historic Shrine; the National Memorial Arch at Valley Forge in Pennsylvania; the town green of Lexington, Massachusetts; and points of entry that are open 24/7.

Hats: Today, this is up to you. Here's what the U.S. Flag Code advises: "When not in uniform men should remove their headdress with their right hand and hold it at the left shoulder, the hand being over the heart. Persons in uniform should remain silent, face the flag, and render the military salute."

Removing one's hat before the flag, although advised by the Flag Code, depends on the circumstances. In this 1932 photograph by Addison Spurlock, church members participating in a group baptism on the Potomac River wear hats while standing under many American flags. Scurlock Studio Records, ca. 1905-1994, Archives Center, National Museum of American History.

Retiring the flag: What do you do with a damaged or worn-out flag? According to the U.S. Flag Code, "The flag, when it is in such condition that it is no longer a fitting emblem for display, should be destroyed in a dignified way, preferably by burning."

Special flag retirement ceremonies have been developed by organizations. The American Legion, for example, holds an "Unserviceable Flags Ceremony" which is officiated by a Sergeant-at-Arms, Commander, and Second Vice Commander and includes formal requests that a flag "honorably retired from further service" before the flag is dipped in kerosene and burned.

The U.S. Scouting Service Project has the practice of cutting the flag into smaller pieces, with special care taken not to cut the blue star field. Scouts then build a wood fire and maintain a vigil until all the flag fragments are then burned.

The American flag often appears at moments of patriotic celebration, but its use is generally guided by the Flag Code. These children in the early 20th century pose with a flag and other star-spangled decorations. This image is from the Faris and Yamna Naff Arab-American Collection, Archives Center, National Museum of American History.

We hope that you bring your new flag knowledge and join the National Museum of American History on June 14, 2014, at 4 PM EDT to add your voice to the largest group sing of the national anthem in history as we celebrate the 200th anniversary of the nation's most iconic symbol: the Star-Spangled Banner. Or, join a singing party near you and tune in to sing along with the nation. Visit the Raise It Up! website to learn more.

Talia Berday-Sacks is an intern with the museum's Food History program.

Curator Judy Chelnick shares what we do know about the mysterious denture in the hopes of filling the gaps.

Here in the museum's Division of Medicine and Science, we're undertaking an inventory of the museum's dental collection, and we discovered one half of an interesting denture. The upper palate appears to be made of silver and it has eight porcelain or mineral tube teeth. Each tooth has a "central canal" which is secured to the palate with pins. Two teeth are missing.

The mystery denture in our collection

The museum's dental collection has dozens of dentures made from these exact materials. What makes this denture interesting are the two inscriptions: In pencil or ink on the top of the palate it reads, "FOUND AT SHILOH BATTLEFIELD"; and etched into the bottom of the palate "FOUND AT BATTLE OF SHILOH".

When curators like myself find a cool object like this, with little identifying information to place it in context, we immediately have a lot of questions. What information can we glean from this artifact? Was it really lost at the Battle of Shiloh? Who lost the denture? What do we know for certain about the denture?

The denture was given to the museum in 1969 by dentist D.L. Crowson of Petal, Mississippi. In a letter to Curator Audrey Davis, Dr. Crowson wrote, "I have no history on this denture except I was told by the person who gave it to me that it had been picked up on the Shiloh battlefield site".

When the Civil War began in 1861, there were few university-trained dentists on either side of the conflict. However, just as now, people suffered from tooth decay diseases that made dentistry as essential on the battlefield as on the home front. The surgical sets supplied to Union surgeons included dental tools for the extraction of teeth. Many of the soldiers who participated in the Battle of Shiloh had probably lost a tooth at some point in their lives, but false teeth would have been relatively rare, especially a denture of this quality.

"Found at the Battle of Shiloh"

Porcelain teeth were developed in 18th century Europe and brought to the United States in the early 19th century. The so-called "tube teeth," artificial teeth with a vertical hole in the center cemented to a metal post attached to the base of the denture, were developed in London around 1840 by Claudius Ash. Gold, silver, tin, lead, and eventually gutta-percha, a plastic cultivated from the sap of trees found in Malaysia, were also common materials used to form the palate in the 19th century. That being said, it is possible that this denture was worn during the war, but how can we know for sure?

Technology has given us some new tools to test our objects without harming them in order to do some material forensics. Here at the National Museum of American History's Object Conservation Lab, Conservator Beth Richwine uses an X-Ray Fluorescence (XRF) Spectrometer to determine the elemental composition of different materials. We took the denture to the lab to have Richwine analyze the metal content of the palate.

Conservation Lab Conservator Beth Richwine uses an X-Ray Fluorescence (XRF) Spectrometer

The XRF found the palate was composed of silver, copper, lead zinc, and bismuth. The analysis showed that the palate was probably an alloy known as German silver, predominantly coin-grade silver, but mixed with small amounts of lead, tin, zinc and bismuth. Richwine explained the trace materials would contribute to the malleability of the metal during processing. "This makes sense because they very well could have been added to the mix to help with the forming process of the palate," she reported. German silver was developed by a German industrial chemist named E. A. Geitner in the early 19th century and was often used in dental applications throughout the 1800s.

Therefore, it is very possible, given the materials and its construction, that the denture is from the time of the Civil War.

But questions remain: Who might have worn this, and how did they lose it? In this period, only the well-off could afford dentures, especially those with a high silver content. So we have to assume the owner was probably an officer, someone with the means to purchase dentures. When the average person lost a tooth, they went without; the unfortunate person walked around with a gaping hole.

Despite all of our evidence, we still do not know for sure if the denture was lost at the Battle of Shiloh and are still left with some unanswered questions. We would love to find a diary entry or letter from the time in which someone mentions dropping their denture on the battlefield to solve our mystery, but so far none has turned up. There is also the grisly possibility that this denture was removed from a corpse, but the high casualties (around 3,400 Americans died at Shiloh) make even this theory a difficult avenue for research.

What do you think? Have we missed an angle? Is there any information you can add to help us solve the mystery of the Shiloh denture?

Judy M. Chelnick is the curator of medical and dental instrumentation in the Division of Medicine and Science at the National Museum of American History. Check out some highlights in our dental history collection in this post by Curator Katherine Ott.