The wheels on the bus aren’t the only things that go around and around! The doors to some buildings do the same thing. What are we talking about? Revolving doors, that is!

Chances are you’ve been through a few revolving doors in your lifetime. They’re very common in large buildings and other places with a lot of foot traffic. You may have seen them at an office building or a shopping mall.

We’ll even bet that the first time you encountered a revolving door you went around and around a couple of times before passing into or out of the building. Didn’t you? Admit it!

And why not? Revolving doors are different and kind of fun. Would you like to have a revolving door on your house? What about your school?

Revolving doors consist of three or four doors — often called wings or leaves — that are spaced an equal distance from each other around a center shaft. They rotate in a circle inside of a cylinder. The cylinder can be small, with just enough space for one person between wings, or it can be large enough to allow several people or even strollers or luggage racks to fit between wings.

The revolving door was invented in 1888 by Theophilus van Kannel from Philadelphia, Pennsylvania. An old urban legend holds that revolving doors were invented to prevent horses from entering buildings. Although that’s funny, it’s not true.

Revolving doors were invented because they have many advantages compared to traditional hinged doors. For example, revolving doors are more energy efficient than regular doors. When you open a regular door, a large amount of air can escape.

Revolving doors limit the amount of air that escapes as the wings rotate through the cylinder. In this way, drafts are reduced and heating and cooling costs are minimized.

Revolving doors also allow more people to enter and exit buildings more quickly. Using a revolving door, people can enter and exit a building at the same time. Regular doors force one person to wait while the other passes through.

Architects like revolving doors because they enhance the entrances of buildings. Not only do they reduce the amount of street noise heard by those inside, they also eliminate the annoying sound of slamming doors.

38 Join the Discussion

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  1. I always try to get my sister stuck in revolving doors when there’s no one else at the store. It’s really fun! I think tomorrow’s WONDER will be about Water Roller Coasters!!!

    Emily =)

    • Hi Emily! We care about all our Wonder Friends and would not want anyone to get hurt. We know that siblings like having fun together but safety is always important, especially when going through revolving doors! :)

      We think you have a SUPER guess for tomorrow’s wild Wonder! Thank you for WONDERing with us today! :)

    • Hi there, Maddison! We are SUPER glad you are learning about revolving doors and doing some WONDERing on your own! Even if your city does not have revolving doors readily available, it’s great that you can still learn about them and why they are so SUPER! Thank you for commenting today– we love great Wonder Friends like you! :)

  2. I really like revolving doors, I once went in one when I was in a hotel at Orlando. It was really fun there, and I’m going back there on my birthday. Oh, and if you spin the revolving door very fast, you can make a funnel of wind. :-)

    • WOW, Carlos, you are one lucky duck! How exciting that you discovered revolving doors in Orlando– and you get to visit again to celebrate your birthday! We think that is SUPER, just like you! :)

    • What a great question, Wonder Friend! We always want to be careful going through doors of any kind, so it’s important to pay attention and stay alert! These doors are energy efficient and, when used properly, are great for getting lots of people in and out of buildings quickly! Thank you for your comment today! :)

  3. Wow I loved that wonder! I wish I had a revolving door in my house! I used to always go around and around in a circle with revolving doors! Reading this wonder it made me think about what the were used for so I looked it up and it said that they were used for conducting traffic in very busy cities and towns!!

    • WOHOO, Kate! We love your enthusiasm for WONDERing with us– and we are so EXCITED that you did some more research on your own. Revolving doors are really great in big cities, and also for keeping inclement weather outside and warm, dry climates inside of big buildings. Great job WONDERing on your own– we think you’re SUPER! If we could, we would give you a great big high five! :)

  4. I have always wondered why there was such a thing as revolving doors! I just thought they were for fun and never thought that it was for many other purposes! When I went to the hospital, there was enough room for three people and a wheelchair! I always go round and round when I am in a revolving door! They are just so fun!

    • Happy Wednesday, Gracie! We LOVE that you learned something new about about revolving doors. How AWESOME that they are purposeful and fun, too! What a STELLAR combination! :)

      We love all the connections you’ve made to this Wonder– we are looking forward to WONDERing with you again! :)

  5. Hello! This is Mr. Morrison’s 3rd Grade class- Jacksonville, Fl. We were wondering how people in wheelchairs get inside of revolving doors?

    Hope to hear from you soon.

    • What a GREAT thing to Wonder about, Mr. Morrison’s third grade students! How interesting that you asked that question, because another Wonder Friend, Gracie, mentioned large revolving doors at hospitals! In her comment above, she mentions a set of revolving doors that were large enough to fit a wheelchair and three other people!

      Just like buildings, revolving doors come in all sizes. When a building’s revolving door does not allow enough room for someone using a wheelchair, a stroller or another type of walking aid, there is a door that swings open available. This is to accommodate those using a walking aid and it is also part of the fire safety plan, too!

      Thank you for posing such a WONDERful question, Wonder Friends! :)

  6. I think revolving doors are awesome. I remember going through one in Chicago. It was a first for me and I loved it! Thanks for the Wonder today. I enjoyed it!!

    • Hi Sir Mack Daddy! Fortunately, there is almost always another door available to you in addition to the revolving door! Have a WONDERful day! :)

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Have you ever wondered…

  • Why are there revolving doors?
  • Who invented revolving doors?
  • Do revolving doors help save energy?

Wonder Gallery

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Try It Out

Open the door to new adventures as you check out one or more of the following activities with a friend or family member:

  • Do you have revolving doors at your house? For most of you, the answer is probably “no.” However, some of you may live in large apartment or condominium buildings that have revolving doors. Wherever you happen to live, spend some time today examining your doors. Are they all the same? Or are some different than others? Some of you may find storm doors on the exterior of the house. These doors are likely quite different than the interior doors in your house. You may also have some sliding glass doors if you have a patio. Have fun taking a closer look at the doors you use every day!
  • Ask an adult to help you examine all the doors in your house for energy efficiency. Do any of them have seals that need to be fixed? Do they open and close easily? If you notice any problems, do what you can to fix them. Have an adult help you by showing you how to make minor repairs to doors. You never know when the simple repairs you make could save your family money on heating and cooling expenses!
  • Ready to use your imagination? Imagine that you’re on a field trip to Planet Wonderopolis. Upon arrival at the Visitor’s Center, you notice that the only way in is through a gigantic revolving door. There’s nothing ordinary about this revolving door, though. It’s magic! When you walk through it, you don’t enter a building. Instead, you enter a random Wonder of the Day that comes to life before your very eyes! You can play this imagination game with your friends. Pretend to walk through a revolving door. When you come out, have your friends select a random number between 1 and 1341. Then head to Wonderopolis to check out the Wonder of the Day with the number they selected. You never know where the Wonderopolis Magic Revolving Door will take you!

Still Wondering

Check out Science NetLinks’ Earth Hour resources to explore the ideas of light pollution, energy conservation and global climate change in the classroom.

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