Fog City Science

Golden Gate Bridge Fog Horn

Golden Gate Bridge Fog Horn

It was a foggy day at the bridge today and our “iconic” fog horns were on all shift. Click here for a wonderful explanation of the speed of sound by Shawn Lani of the Exploratorium and a practical way that you can judge a distance in San Francisco by using the sound of the Golden Gate Bridge fog horns.

Listen to Jim Mcknight, Chief Electrician at the Golden Gate Bridge, talk to KCBS about operating the fog horns on the bridge: Golden Gate Bridge Foghorn Operator Enjoys Blasting Signature SF Sound

Click here for a San Francisco Chronicle newspaper article on the fog horns at the bridge.

Bridge Facts

Looking up the Main Cable at the North Tower“Steel Stretches! When an engineer makes that statement, his listeners are skeptical. But it does, according to the Bridge engineers. They will tell you that due to the constantly varying winds and temperature at the Bridge site, the Bridge is always moving. Take the cables for example. Engineers say if they were detached and laid out on the ground they would be 21 feet shorter than their hanging length. That measurement is the “stretch” caused by the immense load they support. These factors were an important element in the designing of the Bridge, and the elements enter into them…”
— Official souvenir program, Golden Gate Bridge fiesta : celebrating the opening of the world’s longest single span, San Francisco, California, May 27 to June 2, 1937 

The Outdoor Exploratorium in San Francisco has a telescope 2 miles away where you can see the Golden Gate Bridge rise and fall a total of 16 feet depending on the weather.

Here is a link to an online video that shows you the Bridge Thermometer in action.

Update to the Demolition of the 50th Anniversary Brick Walkway at the Golden Gate Bridge

Demolition of the 50th Anniversary Commemorative Brick Walkway.The removal of the commemorative bricks started today and it was a sad occasion for many employees and bridge visitors. Thousands of memories, stories and wishes were loaded into the back of a dump truck and disposed of as nothing more than rubble, a necessary byproduct of progress so that a new “visitor experience” can be constructed for this generation of Bridge Patron.

My heart goes out to the people who purchased these bricks. It is my understanding that the district is offering to send digital photos of individual bricks to anyone requesting them. A Google Earth application is also being developed that will show the pathway as it was before the demolition began today.

If you are interested in receiving a photo, send an e-mail to the district at and include any information you have about the individual brick.

The 50th Anniversary Brick Walkway at the Golden Gate Bridge will be gone by the end of this week

In 1987, as part of the 50th Anniversary Celebration of the Golden Gate Bridge, 7500 personalized bricks were sold to individuals and businesses. A walkway was then constructed at the southeast visitor plaza using these memorial bricks. Starting tomorrow, January 18th, 2012, this brick walkway will be torn out, the bricks discarded and the area brought into compliance with the Americans with Disabilities Act (ADA).

Here is an example of one brick that will disappear:

Janis Joplin was born on January 19, 1943 and 2 days from now, on what would have been her 69th birthday, her memorial brick will be gone. 8 years ago I met the gentleman who was the driving force behind this tribute. Until we met and talked I had not noticed this stone, and I had traveled over it many times. After our encounter I started paying attention to the names and inscriptions on the various bricks. Families, lovers, schools, Institutions and local Broadcast companies are all represented on this pathway.

The Golden Gate National Parks Conservancy is going to create a Commemorative Outdoor Recognition Panel with all 7,500 names engraved alphabetically into it. This will “commemorate these names for years to come and be easier to locate individual names listed.”

The deep-orange color of the bricks stretching out to the vista of the bridge compliments the International Orange color that is known around the world. It is a sight that I will truly miss. While I understand that it would be cost-prohibitive to save the existing bricks and that there is a need to eliminate steep grades for our visitors with disabilities I think that we have missed an opportunity to carry out both of these goals.

I am thinking outside the box here, but what if the bricks were replicated and put back in place on the new compliant walkway/plaza area? My idea is that a fundraising event could add to the number of 7500 old bricks by selling new bricks and expanding the walkway into the plaza surrounding the new exhibits. When setting a price on the new bricks, the cost of replicating the old bricks should be factored in. I think this would honor the original patrons and allow the disabled community to access the Public Area at the bridge.

This is just my opinion and not that of the GGBH&TD or anyone else who works there (to my knowledge).

138 Days to go until the 75th Anniversary of the Golden Gate Bridge!

Photo of Golden Gate Bridge from hillside above Ft PointThe 75th Anniversary celebration of the Golden Gate Bridge is in today’s news. In case you missed it, I have some links to the coverage:

The celebration will take place over two days, May 26th and 27th. I hope to see you there.

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