The Science of Doors

The other day, L was out back in his playhouse, and I noticed he kept opening and closing the shutters on the windows. He has been very interested in opening and closing other doors and cabinets around the house as well. So I decided to do some research on doors and hinges and simple machines. Hinges are actually in the wheel and axle category of simple machines.

eHow says in an article called The Types of Simple Machines Found in Your Home:

Wheels and Axles
Like a lever, a wheel works by rotating around a fulcrum; in this case, the axle. Cars, toys, fans and fishing reels all use wheels and axles. Door hinges are also an example of this device--the round part of the hinge is an elongated wheel. On interior doors, the side attached to the wall and the side attached to the door have multiple wheels that rotate around a common axle.

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  Air and Water says:

  Wheel & Axle The wheel and axle is made up of both a wheel and axle that will rotate together. The wheel and axle is similar to a lever except that the input energy is applied to the end of the wheel which is perfectly balanced around the hinge. The distance from the hinge to the item being pulled shows the mechanical advantage.
  
  Idaho Public Television says:
  Wheel and Axle:
  a wheel and axle has a larger wheel (or wheels) connected by a smaller cylinder (axle) and is fastened to the wheel so that they turn together. When the axle is turned, the wheel moves a greater distance than the axle, but less force is needed to move it. The axle moves a shorter distance, but it takes greater force to move it. Examples: Door Knob, Wagon, Toy Car
  
  
  

  

  
  
  Now, of course our babies and toddlers and even preschoolers are not quite ready to understand all this yet.  But it is important that we understand so that we can teach them properly when they start asking us questions. For the very young children who aren't talking yet, just allowing them to explore with opening and closing doors is good. Some doors close automatically and some don't. There are doors that slide, doors that revolve, and doors that lift. 
  

  

  
  
  For children who are a little bit older, encourage them to ask questions. An example is "Why do hinges creak?" Chances are, the children will come up with better questions than we can. The key is to allow them to do the research and show them how to find the answers on their own. Google is an excellent resource of course, but providing them with materials to do experiments on their own will make a far bigger impression on them. They will remember what they learned better if they learned it own their own by trial and error. 
  

  

  
  

  Here are some pictures of doors we found around the house and neighborhood. Just look around and I'm sure you will find a lot more doors than you thought you had!

  
  

  

  
  

  

  
  

  

  
  

  

  
  

  

  
  

  

  
  

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