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Teachers and technicians are in awe of the PASCO Diffusion Cloud Chamber as demonstrated by Helen Rose, Laboratory Manager and Technician Professional Development Leader, at the National STEM Learning Centre

Dedicated to providing high-quality support to educators, STEM Learning is the UK’s largest provider of education and careers support across science, technology, engineering and mathematics (STEM) disciplines. Delivering bespoke CPD courses for both teachers and technicians, STEM Learning has a very active role in enhancing the teaching and learning of STEM subjects and is considered one of the top advisory bodies within UK education.


Traditionally, cloud chamber demonstrations have been known to be a nuisance. With cumbersome setup methods, a great deal of organisation and planning has been required to successfully deliver this demo on a given day. One of the biggest challenges is the sourcing, handling and storing of dry ice: a hazardous substance with a short shelf life. Unable to store dry ice in a freezer (following CLEAPSS guidelines), this needs to be sourced at a time close to the delivery of the demo, leaving very little room for error. The use of dry ice for cloud chambers perpetuates running costs and preparation times that ultimately shroud this activity in a negative light.

Helen Rose
The PASCO Diffusion Cloud Chamber, as demonstrated by Helen Rose, Laboratory Manager and Technician Professional Development Leader, at the National STEM Learning Centre


As a previous School Science Technician, Helen was all too familiar with the struggles associated with traditional cloud chambers. During her role at the STEM Centre, Helen came across the PASCO diffusion cloud chamber and it opened her eyes as to how effortlessly this demo could be run with a Peltier-based system. With no dry ice requirements, radioactive processes can be demonstrated with ease, offering an avenue to change educators’ perceptions towards this curriculum-relevant demo.


“As soon as I saw the PASCO cloud chamber in action, I knew it was something that I wanted to share with the rest of the teaching community. It’s so easy to set up and it begins working very quickly, with clear tracks visible in around 10 minutes. The cloud chamber really is one of my favourite pieces of Physics equipment. We’ve had our set for eight years now and they’ve all been very reliable, living up to the high standard that you’d expect from PASCO. I recommend this cloud chamber during my CPD sessions predominantly because of the ease of preparation: it is poles apart from the laborious dry ice versions, and really nothing can go wrong with the PASCO setup, and so teachers and technicians can confidently provide this demo time and time again, with little to no notice.

We either use ours with a red tip thorium welding rod to show alpha and beta radiation, or without a source to show cosmic rays. With the large viewing chamber, the tracks are very visible, and in light of the current COVID crisis, I’m also recommending the use of a visualiser with the apparatus, to maintain social distancing rules within the classroom/laboratory. Although it is more expensive than some other versions, I’d say it is excellent value for money and budget well spent as schools will get their money back within 1-2 years from the savings on dry ice costs.

It is easily the best cloud chamber I’ve ever seen and worked with.” – Helen Rose , Laboratory Manager and Technician Professional Development Leader at the National STEM Learning Centre 


The Diffusion Cloud Chamber is used to view high energy alpha particles, lower energy beta particles, and electrons produced by gamma rays interacting with gas molecules. The Chamber allows for the viewing of cosmic rays without the need for dry ice or external illumination. Explore the PASCO Scientific Diffusion Cloud Chamber more here.