Pendulum Bobs or Spheres
Product Code : EL-POM-10362
Quick answer: Pendulum bobs or spheres are solid turned metal balls with a small hook for suspension, made in 12, 18 and 25 mm sizes in brass, aluminium, copper, zinc, iron and lead. They are used for simple pendulum experiments and for density and specific gravity comparisons. Lab Exports manufactures them in Delhi for schools, colleges and universities.
Specifications
| Attribute | Detail |
|---|---|
| Shape | Solid turned spheres with suspension hook |
| Sizes | 12 mm, 18 mm, 25 mm |
| Materials | Brass, aluminium, copper, zinc, iron, lead |
| Purchase options | Full set or individual pieces |
| Custom options | Other sizes and materials, including non-metals, on demand |
How the bobs are used
In the simple pendulum experiment a small, dense bob hangs on a light thread, and the period of small swings is T = 2 pi sqrt(L / g), where L is measured from the point of suspension to the centre of the bob. A spherical bob makes that centre easy to locate: add the radius to the thread length. Timing 20 oscillations at several lengths and plotting T^2 against L gives a straight line of slope 4 pi^2 / g, from which g is found.
- Tie the hook of the bob to a light, inextensible thread and clamp the thread between split cork pieces.
- Measure the thread length and add the radius of the bob to get L.
- Displace the bob through a small angle and release it without pushing.
- Time 20 oscillations, find T, and repeat for other lengths.
Swinging bobs of the same size in different metals shows that the period does not depend on the mass of the bob, while the denser metals keep swinging longer against air resistance. The same spheres serve for density measurements, using V = (4/3) pi r^3.
Key features
- Solid turned spheres, so the centre of mass lies at the geometric centre.
- Small hook on each bob for suspension.
- Three sizes: 12 mm, 18 mm and 25 mm.
- Six metals: brass, aluminium, copper, zinc, iron and lead.
- Available as a full set or as individual pieces, with custom sizes and non-metals on demand.
Documentation and supply
Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the pendulum bobs 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.
Related Properties of Matter products
- Metal Cubes (EL-POM-10361)
- Air Pump (Vacuum Pump with Aluminium Plate) (EL-POM-10363)
- Metal Cylinder (EL-POM-10360)
- Bell Experiment Apparatus (EL-POM-10364)
- U-Tube Manometer on Stand Table Model (EL-POM-10359)
- Portable Diaphragm Type Vacuum Pump cum Air Compressor, Oil Free, Light Weight (EL-POM-10365)
The full range is in the Properties of Matter section of the Physics Lab range.
Frequently asked questions
What sizes of pendulum bob are available?
12 mm, 18 mm and 25 mm.
Does the mass of the bob change the period of a pendulum?
No. For small swings the period depends only on the length and g, which is why bobs of different metals give the same period at the same length.
What is the price of the pendulum bobs?
Prices are not published on the website. Add the pendulum bobs to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-POM-10362 and the quantity, to receive a quotation.
Does Lab Exports manufacture the pendulum bobs?
Yes. Lab Exports manufactures the pendulum bobs at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-POM-10362.
Request a quote
Email [email protected] with the house code EL-POM-10362 and the quantity, or add the pendulum bobs to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.
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