The instrument, named, `Instant Gas Set' is considerbaly time and cost- efficient, easy to handle and most importantly, prevents the release of the gas - which causes pollution and is a known cause of cancer - into the environment.

Kamlamkar felt the need to come up with a replacement, as during years of laboratory work, he noticed several drawbacks in the Kipp's Apparatus.

The apparatus, due to its size and method of operation, requires a large quantity of reagents for the production of gas. The requirement is about three to four litres of Hydrochloric (HCL) or Sulphuric acid (H2SO4) and half to one kg of ferrous sulphide (FeS). The quantity of gas formed at one go is also quite large, often not required for experiments in the laboratory.

Moreover, there is no externalcontrol on the reaction. To stop the reaction, the student has to close a valve. The reaction, however, continues for some time even after the valve is closed and the gas forms in the middle bulb creating pressure on the reagents, which then separate, stopping the reaction.

This method of stopping the reaction is considered the biggest achievement of the Kipp's Apparatus. However, it is at this point that its most serious flaw exists. As the apparatus is not air tight, there is leakage and the reaction continues, leading to continuous production of gas.

As the gas is produced in a large quantity, quite an amount of it escapes into the atmosphere when the students handle the apparatus. Many a time, the reaction process goes awry and several accidents have been recorded due to the overflow of the acid from the uppermost bulb of the apparatus. Also, when a student opens the valve the next day, the previous day's gas comes out forcefully, causing pollution.

The reaction waste collects in the bottom bulb andthere is need to wash the apparatus for further use, causing wastage of reagents. As the apparatus is costly (Rs 1,500), few small schools, particularly those in rural areas, can afford it.

On the other hand, the Instant Gas Set is a very simple apparatus, costing roughly Rs 20. It uses two glass tubes, about 50 cm in length, which are joined in a U-shape with a plastic tube about 4.5 feet in length.

It performs all the functions of the Kipp's Apparatus, but is more efficient. Moreover, the reaction can be stopped immediately by separating the reagents.

The quantity of reagents to be used is very less and can be adjusted according to the need (depending upon the number of students conducting the experiment). About 30-40 gms of FeS and 300-400 ml of HCL/H2SO4 is required for a batch of 40-50 students.

As the reagents are in a vertical column, the amount of FeS that is to be reacted with acid can be controlled. Similarly, the rate of reaction can be controlled. Thus, as against the Kipp's Apparatus, theexperiment can be conducted with full external control.

The reaction can be stopped in a jiffy. As the empty space in the gas-forming tube is very small, gas separates them out easily. Also, when the students handle the apparatus the next time around, a small amount of gas comes out, preventing release of extra gas in the environment. Due to the immediate stoppage of reaction and complete separation of reagents, there is no fear of acid overflow or gas leakage either.

An extra loop in the plastic tube at the base of apparatus is useful for saving the acid. The waste reagents, following the experiment, get collected in the U-loop and while washing the apparatus only a part of the acid is to be thrown away. Also, the amount of FeS required for preparation of gas could be pre-decided.

The apparatus has been selected by the All India Science Teachers' Association in its national screening of scientific models. It will now be forwarded to the National Council of Education, Research and Training, forinclusion in the school syllabus.