Magdeburg Spheres: Difference between revisions

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Please read the Physical Demonstration section of the [[Demonstration Safety]] page before performing this demonstration.
Please read the Physical Demonstration section of the [[Demonstration Safety]] page before performing this demonstration.
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== Demonstration ==
== Demonstration ==


# Steps for the demonstration.
;Presentation (Stage):
# Be sure to clarify on steps about any safety equipment needed.
# Show the two halves of the Magdeburg sphere, and that they don't stay together well when you press them into each other. Open the valve on the side of the sphere, and hook it up to the vacuum pump.
# Make sure steps can be understood by a first-time reader.
# Use the vacuum pump to suck the air out of the sphere, and close the valve on the sphere before turning off the pump. Detach the sphere from the pump, and show that you can no longer pull it apart.
# Ask for two volunteers, and have them each take a handle on the Magdeburg sphere. Have them tug at the sphere to try to open it again, but they can't! Take the sphere from them, and then open the valve to let air back inside. It falls right open!


== Why This Works ==
== Why This Works ==


===Short Explanation===
The Magdeburg sphere was first created by Otto von Guericke, and demonstrated publicly in 1654 in Magdeburg, Germany. He developed the sphere as a way to demonstrate how strong ''Air Pressure'' can be, which is the pressure we experience from the air around us at all times. By hooking the sphere up to a vacuum pump, we are able to remove almost all of the air inside the sphere, making a ''Vacuum'', or an empty space inside. Since there is nearly no air inside the sphere, and there is a lot of air outside the sphere, the pressure outside the sphere will be much greater than inside. This means that, as hard as anyone tries to pull the two halves apart, the air outside the sphere will push ''even harder'' to keep the sphere shut!
This is where you would provide a basic, easy-to-understand explanation of the demonstration. Try not to use too much "Science Jargon", and if needed add any explanation tips, like comparing the demo to something kids are familiar with.
 
===Full Explanation===
This is where you will explain the demonstration in full, and provide all additional information that pertains to the demo. Unlike the short explanation above, this should be worded so someone who is familiar with the topics might understand it. If needed, you can provide equations and citations for additional sources of information on the topic. This is also where you will find some answers for trickier questions, such as "How does a plane fly upside-down?" for the Bernoulli's Principle demo. If you want to add a floating box for equations, copy the following:
 
{| class="wikitable" style="color:black; background-color:#ddd; text-align: center; margin: auto"
| This will give you
| a floating box.
|-
| The box will be
| centered for you.
|}


== Additional Information ==
== Additional Information ==


* Any extra tidbits that do not fit into other sections
* This demonstration pairs well with the [[Crush The Can]] and the [[Marshmallow Smashies]] demonstrations.
* This demonstration is a part of the (insert [[Stage Show]] here)
* This demonstration is a part of the [[Pressure Show]]
-->

Latest revision as of 20:21, 1 September 2016

Physics: Vacuums, Air Pressure
Grade Range: Elementary School, Middle School, High School
Format: Hands-on, Stage

The Magdeburg spheres are a classic demonstration for introducing vacuums and air pressure. They are a fun demonstration for older audiences, especially when you have two strong students try and fail to pull the sphere open!

Materials

  • Magdeburg Spheres
  • Vacuum Pump

Safety Precautions

Please read the Physical Demonstration section of the Demonstration Safety page before performing this demonstration.

Demonstration

Presentation (Stage)
  1. Show the two halves of the Magdeburg sphere, and that they don't stay together well when you press them into each other. Open the valve on the side of the sphere, and hook it up to the vacuum pump.
  2. Use the vacuum pump to suck the air out of the sphere, and close the valve on the sphere before turning off the pump. Detach the sphere from the pump, and show that you can no longer pull it apart.
  3. Ask for two volunteers, and have them each take a handle on the Magdeburg sphere. Have them tug at the sphere to try to open it again, but they can't! Take the sphere from them, and then open the valve to let air back inside. It falls right open!

Why This Works

The Magdeburg sphere was first created by Otto von Guericke, and demonstrated publicly in 1654 in Magdeburg, Germany. He developed the sphere as a way to demonstrate how strong Air Pressure can be, which is the pressure we experience from the air around us at all times. By hooking the sphere up to a vacuum pump, we are able to remove almost all of the air inside the sphere, making a Vacuum, or an empty space inside. Since there is nearly no air inside the sphere, and there is a lot of air outside the sphere, the pressure outside the sphere will be much greater than inside. This means that, as hard as anyone tries to pull the two halves apart, the air outside the sphere will push even harder to keep the sphere shut!

Additional Information