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Instruction Sheet

3B SCIENTIFIC® PHYSICS

U45054 Magdeburg Plates

7/03 ALF

Complete set of equipment for conducting Guericke’s

historical experiment to show the effect of atmospheric

pressure. The experiment can be performed as a dem-

onstration or as a student practical.

1. Safety Instructions

• Do not try to pry the two evacuated hemispheres

apart using tools.

• Do not try to separate the hemispheres using ropes

or similar, because when they do separate they can

turn into projectiles.

• Ample space should be left behind the persons try-

ing to separate the Magdeburg plates

• Do not use excessive force when connecting the

hose. Do not use any more force than you can gen-

erate from your fingers to connect the hose.

• When ventilating the hemispheres hold on tight to

the apparatus so that you can avoid any damage

from the hemispheres falling.

• Be careful not to scratch the inner surfaces of the

plates.

• To clean, only use warm water with a small amount

of washing-up liquid. Never use solvents.

Description, technical data

The Magdeburg plates kit consists of two transparent

acrylic plates with handles and a rubber sealing ring

to be placed between them. They can be pushed to-

gether with a coarse vacuum between them. Sealing

rings of two different sizes allow comparison between

the effects of atmospheric for two differing contact

areas. One plate is equipped with a flange for attach-

ing a plastic hose so that a vacuum can be generated.

Evacuation is performed using a simple hand pump.

This can be connected via a plastic-hose with a built-

in valve. An additional T-piece allows a pressure sen-

sor (e.g. U44220) to be connected for measuring pres-

sure in conjunction with a suitable interface (e.g.

LabPro U44000).

The advantage of the Magdeburg plates over the hemi-

spheres usually used in lessons is that, due to the flat

design, all forces act parallel to the plates allowing the

forces to be calculated easily.

Transparent acrylic plates: 13 mm x 97 mm Ø

Sealing rings: 5 mm x 85 mm Ø

inside

and 95 mm Ø

outside

5 mm x 50 mm Ø

inside

and 60 mm Ø

outside

2.1 Scope of delivery

2 Transparent acrylic plates with handles

2 Rubber sealing rings of different diameters

1 Hand pump in storage case

1 Hose with valve

1 Hose with T-piece and valve

1 T-piece

1 Spare hose connector

1 Hose with T-piece and valve

2 Hose with valve

3 Transparent acrylic plate with flange for hose attachment

4 Transparent acrylic plate

5 Rubber sealing rings

6 T-piece

7 Spare hose connector

8 Hand pump

7 8

Summary of content (3 pages)

PAGE 1
® 3B SCIENTIFIC® PHYSICS U45054 Magdeburg Plates Instruction Sheet 7/03 ALF 4 3 1 2 3 4 5 6 7 8 2 1 5 6 7 Hose with T-piece and valve Hose with valve Transparent acrylic plate with flange for hose attachment Transparent acrylic plate Rubber sealing rings T-piece Spare hose connector Hand pump 8 Complete set of equipment for conducting Guericke’s historical experiment to show the effect of atmospheric pressure. The experiment can be performed as a demonstration or as a student practical.
PAGE 2
3. Operating principle 1 A protective mantle of air called the atmosphere surrounds the earth. The air molecules like all other materials are subject to the force of gravity and thus become concentrated at the earth’s surface. The atmospheric pressure, which is exerted by the air mass, is highest at sea level and gradually decreases with increasing distance from the earth’s surface. Air pressure like any liquid exerts equal and constant pressure on all sides of an object.
PAGE 3
• • • • • • • Pump out the air between the plates. The force acting on the Magdeburg plates can be determined by the equation Force = Pressure x Area. It should be noted that some residual air remains between the plates that acts against the atmospheric pressure. This should be considered when calculating the force: Force = (Atmospheric pressure – Residual pressure) x Area Use the pressure sensor to work out the pressure due to the residual air between the plates.