The larger SONICA ultrasonic cleaners have proved paramount for washing
glassware at school science and chemistry laboratories.
At the Gonzaga Institute in Milan, an 18-litre cleaner enables students to wash
the instruments used in lessons and experiments both thoroughly and fast.

Prof. Domenico Fraccalvieri, Science teacher and Laboratory Teaching Assistant in both the Laboratories of Chemistry and Physics at Gonzaga Institute in Milan tell us how they are using Ultrasonic Cleaning Technology inside their laboratories.

Istituto Gonzaga (see Fig.1-3) was founded in 1906 by the religious congregation of the “Brothers of the Christian Schools”, founded in 1680 by St. John Baptist de La Salle universal educators’ patron. The High Schools of Istituto Gonzaga guarantee a high quality and complete educational path (arts, science, humanities) aimed to that breadth of thought which is a peculiar heritage and legacy of our civilization and of the high school tradition by itself.

At the High Schools’ scientific laboratories, we tested the ultrasonic bath SONICA 4300ETH S3 (18 liters).
The main application of this machine is the washing of both laboratory glassware and
support tools used for teaching laboratories purposes of both Sciences (Chemistry, Biology and Earth Sciences) and Physics.
In particular some experiences of Chemistry, carried out by more classes in a short
sequence, have the problem of both a large amount of tools to be washed and different kinds of chemicals to be removed.
Moreover, the tools have to be quickly reused by the next classes.
As an example, an experience to study the solubility of different solid compounds with
different liquid solvents involves the use of about 90 test tubes for each class using
both organic and inorganic solvents and both hydrophilic and hydrophobic solids compounds.
In this case, by using the ultrasonic washing machine we were able to wash more
than 60 test tubes in 5 minutes, directly into their test tube rack.
In the case of test tubes, another successfull apllication was the complete removal of both stains and spots of iron hydroxide by coupling the use of ultrasonic washing machine and an acid detergent.
In the laboratory of Physics the complete removal of vegetable oils residues poured into graduated cylinders (experiments to study the motion of bodies) was not an easy task.
By using the ultrasonic washing machine also this operation was successfully accomplished coupling ultrasounds and high temperature (40°C).Finally an interesting application was the washing of an instrument to study the communicating
vessels (see Fig. 2) .

This tool (c.a. 60 years old) is particurarly delicate and by hand washing it is virtually impossible to remove the oil residues in the narrow brassy joints.

Even in this case by using the ultrasonic washing machine we obtained a satisfactory cleaning of glass vessels and we also cleaned the brassy sections.
Therefore, the final judgment is positive and the main advantages are:

• a faster washing of the laboratory glassware;
• the ability to clean not hand washable tools.

Prof. Domenico Fraccalvieri
Science teacher and Laboratory Teaching
Assistant in both the laboratories
of Chemistry and Physics
Istituto Gonzaga, Milano

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