Lee's And Charlton's Apparatus
Product Code : EL-H-10400
Quick answer: Lee's and Charlton's Apparatus measures the thermal conductivity of thin layers of poor conductors such as card, glass or ebonite. A thin specimen is placed between a brass steam chest and an 11 cm brass slab hung by three strings; steady temperatures and the slab's cooling rate give K. Lab Exports manufactures it in Delhi for colleges and universities.
Specifications
| Item | Specification |
|---|---|
| Brass slab | Cylindrical, 11 cm diameter, 10.5 mm thick, radial thermometer hole |
| Suspension | Three strings from a stout annular ring |
| Steam chest | Brass hollow cylinder, 4.5 cm deep, same diameter as the slab, with inlet and outlet tubes |
| Stand | Heavy retort stand |
| Alternative slab | Iron cylindrical slab of the same size |
| Thermometer | Not included |
How the Lee's disc experiment is done
Lee's method finds the thermal conductivity of a poor conductor in two stages. First, a thin disc of the specimen is sandwiched between the steam chest and the brass slab until the temperatures of the chest (T1) and the slab (T2) are steady; the heat flowing through the specimen then equals the heat the slab loses to the air. Second, the slab alone is warmed a few degrees above T2 and its cooling rate dT/dt at T2 is found. Neglecting edge losses, K = m c (dT/dt) x / (A (T1 - T2)), where x is the specimen thickness and A its area.
- Hang the brass slab by its three strings from the annular ring on the retort stand and lay the specimen disc on it.
- Place the steam chest on the specimen, insert thermometers to read the chest and slab temperatures, and pass steam through the chest.
- Wait until both readings are steady and record T1 and T2.
- Remove the specimen, warm the slab directly against the chest to about 10 deg C above T2, then let it cool alone, noting its temperature every 30 seconds.
- Plot the cooling curve, find the slope at T2 and calculate K.
Key features
- Cylindrical brass slab, 11 cm in diameter and 10.5 mm thick, with a radial thermometer hole
- Slab hung on three strings from a stout annular ring so it sits level
- Brass steam chest 4.5 cm deep with inlet and outlet tubes, matched to the slab diameter
- Heavy retort stand to support the assembly steadily
- Iron slab of the same size available as an alternative to brass
Documentation and supply
Installation instructions and a manual are supplied with the apparatus. Most Lab Exports products carry a one-year manufacturer warranty.
Lab Exports manufactures the Lee's and Charlton's apparatus at its works in Laxmi Nagar, Delhi, and supplies it to 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 Heat products
- Searle's Thermal Conductivity Apparatus (EL-H-10399)
- Joule's Calorimeter (EL-H-10401)
- Linear Expansion Apparatus (EL-H-10398)
- Callendar and Barne's Apparatus (Continuous Flow) (EL-H-10402)
- Pyrometer (EL-H-10397)
- Constant Level Tank (EL-H-10403)
The full range is in the Heat section of the Physics Lab range.
Frequently asked questions
What does Lee's and Charlton's apparatus measure?
The relative thermal conductivity of thin layers of poorly conducting materials, by the steady-state disc method.
What size is the brass slab?
The slab is cylindrical, 11 cm in diameter and 10.5 mm thick. An iron slab of the same size is also available.
Is a thermometer included?
No. The apparatus is supplied without thermometers; they can be added to the same enquiry.
What is the price of the Lee's and Charlton's apparatus?
Prices are not published on the website. Add the Lee's and Charlton's apparatus to the Enquiry Cart with the Add To Cart button on this page, or email [email protected] with the house code EL-H-10400 and the quantity, to receive a quotation.
Does Lab Exports manufacture the Lee's and Charlton's apparatus?
Yes. Lab Exports manufactures the Lee's and Charlton's apparatus at its works at 11/315, Lalita Park, Laxmi Nagar, Delhi 110092, under house code EL-H-10400.
Request a quote
Email [email protected] with the house code EL-H-10400 and the quantity, or add the Lee's and Charlton's apparatus to the Enquiry Cart with the Add To Cart button on this page. Tender buyers can also see the Tenders and OEM page.
