Bell Experiment Apparatus
Product Code : LSK-POM-11191
Bell Experiment Apparatus (SKU LSK-POM-11191) is a 2 litre bell jar with an electric bell hung from its rubber stopper, used to show that sound cannot travel through a vacuum as the air is pumped out. It is a classic sound demonstration for secondary school science and college physics. Made by Science Lab Supplies in its factory at Plot 448, HSIIDC Industrial Area, Saha, Ambala, India, the apparatus goes straight from the manufacturer to schools, colleges, tender contractors and distributors.
Specifications
The table lists the bell-in-jar unit's specifications one by one. In short, a 2 litre bell jar is closed by a rubber stopper carrying binding posts and connectors, an electric bell hangs inside from the stopper, and the bell runs on 3 to 6 volts from either a battery or a transformer.
| Specification | Value |
|---|---|
| SKU | LSK-POM-11191 |
| Bell jar capacity | 2 litre |
| Closure | Rubber stopper |
| Stopper fittings | Binding posts and connectors |
| Bell | Electric bell suspended from the stopper |
| Operating voltage | 3 to 6 V |
| Power source | Battery or transformer |
| Pump | For use with Air Pump (Vacuum Pump with Aluminium Plate) |
| Demonstrates | Sound cannot be transmitted through a vacuum |
| Manufacturer | Science Lab Supplies, Saha, Ambala, Haryana |
| Country of origin | India |
Applications and Experiments for the Bell Experiment Apparatus
With the bell ringing inside the jar, students hear the sound fade as the pump removes air and return when air is let back in. The set links directly to the Class 9 chapter on sound and is a clear piece of school physics lab equipment in India for teacher demonstrations.
- NCERT Class 9 (Sound): showing that sound needs a material medium, with the air removed by the Air Pump (Vacuum Pump with Aluminium Plate).
- Comparing loudness at stages of evacuation, measured outside the jar with a Digital Sound Meter.
- Wiring the bell to the binding posts from a battery or a low-voltage source such as the Multitap Transformer, which has a 3 V tapping.
- Discussing why the bell can still be seen vibrating while its sound is no longer heard.
Keep the supply within 3 to 6 volts and treat the evacuated jar as an implosion risk: use a safety screen and admit air slowly.
Standard Scope of Supply
Each apparatus comprises the 2 litre bell jar, the rubber stopper with its binding posts and connectors, and the electric bell suspended from the stopper. The vacuum pump and the battery or transformer are not part of the set and can be quoted with it on request.
Packing, MOQ and Lead Time
Request a quotation for one apparatus or for several to equip parallel sound demonstrations. Science Lab Supplies prices each quotation for the stated quantity and gives its packing and delivery time, and the matching air pump and a power source can be listed on it as well.
Holding an Importer-Exporter Code, Science Lab Supplies is able to ship to buyers in Qatar, Sri Lanka, Vietnam, Malaysia, Peru and Egypt. To price the bell experiment for your science department, message the team via the contact page, use the enquiry cart, or consult the lab tender page for tendered purchases.
Frequently Asked Questions
What voltage does the Bell Experiment Apparatus need?
The electric bell operates on 3 to 6 volts. It can be powered either by a battery or by a transformer connected to the binding posts on the rubber stopper of the jar.
Which pump should be used with it?
The apparatus is specified for use with the Air Pump (Vacuum Pump with Aluminium Plate), which removes the air from the jar so that the fading of the bell's sound can be heard.
Why does the bell become quieter as air is removed?
Sound travels as vibrations passed from particle to particle. As the pump lowers the amount of air in the jar, fewer particles carry the vibrations of the bell to the glass, so less sound reaches the class.
Where is the apparatus made?
Science Lab Supplies manufactures and assembles it at its own unit in Saha, Ambala, India, so buyers deal with the maker for price, packing and dispatch rather than with an agent.
Related Vacuum and Sound Apparatus
The vacuum and sound items below either produce the reduced pressure this demonstration needs or extend the same lessons on air pressure and the behaviour of sound, and each can be priced on the same quotation as the bell experiment.
- Bell Jars — vacuum demonstration unit for use with a hand pump or an electric vacuum pump.
- School Vacuum-Pump Set — bell-jar set listed for vacuum fountain, evaporation icing and sound demonstrations.
- Microscale Vacuum Apparatus with Hand Pump — lets students expand a balloon or boil warm water in a small bell jar.
- Hand Vacuum Pump with Pressure Gauge — pumps 15 ml per stroke and displaces up to 725 ml of air.
- Law of Reflection of Sound Apparatus — measures incident and reflected angles of sound off flat surfaces.
- Magdeburg Hemispheres — concave cups of 62 mm or 75 mm diameter with handles and a stop cock.
- Portable Diaphragm Type Vacuum Pump cum Air Compressor, Oil Free, Light Weight — low-vacuum pump for continuous running without oil vapour.
Browse the full Properties of Matter range, the Physics Lab range for bell jars and sound apparatus, or all physics lab equipment.
Last updated: 9 October 2026