Magdeburg Hemispheres

Product Code : EL-POM-10366

Specifications

How the Magdeburg hemispheres experiment is done

The experiment repeats, on a bench scale, the seventeenth-century demonstration by Otto von Guericke in the town of Magdeburg. With air both inside and outside, the pressures on the two cups balance and they separate easily. Once the air inside is pumped out, only the atmosphere pushes on the outer surfaces, and the force holding the cups together is atmospheric pressure multiplied by the cross-sectional area of the sphere, F = P x pi r^2.

With a perfect vacuum, a 75 mm pair would need a pull of roughly 450 N to separate, and a 62 mm pair about 300 N. A school pump removes most but not all of the air, so the real force is lower, yet it is still easily felt by students.

1. Smear a thin film of vacuum grease on the rims so that the two cups seal when pressed together.
2. Join the hemispheres with the stopcock open and connect the stopcock to a vacuum pump with rubber pressure tubing.
3. Pump out the air, then close the stopcock and disconnect the pump.
4. Ask two students to pull on the handles and feel the force needed to separate the cups.
5. Open the stopcock to let air back in; the cups now come apart without effort.

Key features

• Two concave hemispherical cups that seal together at the rim
• Choice of 62 mm or 75 mm diameter
• Available in brass or aluminium
• Handles for a firm pull on each half
• Stopcock that holds the vacuum after the pump is disconnected

Documentation and supply

Most Lab Exports products carry a one-year manufacturer warranty.

Lab Exports manufactures the Magdeburg hemispheres at its works in Laxmi Nagar, Delhi, and supplies it to schools, colleges and universities in India and 60+ countries, handling the export documents for each shipment. More about the company is on the About Lab Exports page.

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The full range is in the Properties of Matter section of the Physics Lab range.

Frequently asked questions

What do Magdeburg hemispheres demonstrate?

They demonstrate atmospheric pressure: once the air between the cups is removed, the pressure of the outside air holds them together.

Which sizes and materials are available?

The hemispheres are made in 62 mm and 75 mm diameter, in brass or aluminium.

What else is needed for the experiment?

A vacuum pump, such as the Lab Exports air pump with aluminium plate or the diaphragm vacuum pump, connected to the stopcock with rubber tubing.

What is the price of the Magdeburg hemispheres?

Prices are not published on the website. Add the Magdeburg hemispheres to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-POM-10366 and the quantity, to receive a quotation.

Does Lab Exports manufacture the Magdeburg hemispheres?

Yes. Lab Exports manufactures the Magdeburg hemispheres at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-POM-10366.

Request a quote

Email [email protected] with the house code EL-POM-10366 and the quantity, or add the Magdeburg hemispheres to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.