Hands-on physics experiments with SEN school

Prepared by Luke Smith, Joe Cregeen, Lauren Doyle and Martha Turvey

Activity details

Physics outreach with Exhall Grange special educational needs (SEN) school. General theme of ultrasound – demonstrations included an interactive session finding hidden voids in an aluminium block, playing with a Chladni plate, and a demonstration of a tornado in a box (with water mist generated ultrasonically to visualise the vortex). The aim of the visit was mostly as a fun day out, but with the teachers help we managed to link in a lot of topics they had been learning about in their science classes.

Who was involved?

• Beth Sharp (Postdoc)
• Joe Cregeen (PhD student)
• Martha Turvey (PhD student)
• Luke Smith (PhD student)
• Lauren Doyle (Research Fellow)
• Ally Caldecote (Senior Teaching Fellow)
• Alan Burton (Technician)
• David Hudson (Technician)

All from the Physics Department.

Who with?

Year 11 of Exhall Grange School (~23 students, plus teachers).

When?

20^th March 2024, 10:00-12:15

Where?

Physics undergraduate labs, chosen because of the large spaces available and ease of access.

Needs/ requirements communicated before event

• Wheelchair access (2 regular wheelchairs, 2 power chairs)
• Disabled toilet access
• Changing places toilet access (with hoist)
• One student visually impaired (no vision at all)
• Noise sensitivity – need to make provisions e.g. ear defenders and quiet space
• Some students working at lower key stage level

Plan & delivery

The plan was to split the students into two groups. One group would go with Beth, Luke and Alan to do the Chladni plate and tornado demonstrations, and the other would go with Joe, Martha and Lauren to do the interactive lab session. Then we would switch the groups and repeat.

Chladni Plate Demonstration

The session started with a short talk about what a Chladni plate is, and why the way it vibrates causes the salt to settle into cool patterns at certain frequencies of vibration. We warned about the noise that the plate makes, and handed out ear defenders to everyone – they could just hold them if they wanted to, but we knew that if everyone was holding a pair then at least some would use them, especially when we started using higher frequencies. There was also a door separating off the area next to the experiment so that students could leave if they wanted to, and we told them that it was okay to leave at the start of each session.

This demo, whilst noisy, is extremely visual – you’re looking at salt settling into patterns on a plate. We knew that it wouldn’t be engaging for the visually impaired student if we didn’t do something to accommodate for them. Joe thought of the idea of 3D printing the shapes of the plate at different frequencies to make the experience completely tactile, so Luke did 3D models of them. Luke, Joe, Martha and Beth then tested the experiment before the day to make sure the patterns matched up, and recorded the frequencies of the ones that we chose to print. The idea was to make sure that the visually impaired student was getting an equivalent experience – feeling the same patterns that the other students were seeing on the plate.

On the day, the session was run slightly differently for the two groups. The first group did not contain the visually impaired student, so the 3D printed plate shapes were passed around the group to help explain why the salt behaves the way it does. The way we did the demo was to find the resonant modes manually using a frequency dial, which helps to demonstrate that the resonances only occur in very narrow windows of frequency. For the other group, Beth sat with the visually impaired student with the 3D prints in front of her. Luke stood at the front doing the demo but rather than manually finding the frequencies which generated a pattern, he used a function generator to skip directly between the patterns that matched up to the 3D prints – this meant Beth could hand over the prints as they were displayed for the rest of the class.

Tornado Demonstration

This demo is a large Perspex box which has a bowl of water at the bottom with an ultrasonic mister inside (like a humidifier, but more powerful). A fan at the top pulls air up, but the only place it can come in from is along the vertical edges of the box, which causes a vortex to form inside. It is lit with colourful LED lights and a laser which lets you see a ‘slice’ through the eye of the tornado. Alan built this for general outreach use and this was its first use – it went down extremely well.

The demo started with a short talk from Alan about how it worked. Then he turned on the ultrasonic mist generator and showed water misting up out of the bowl. Next the fan got turned on – doing it this way allowed the students to see how the different parts come together to make the tornado. After demonstrating how the lights changed colour, fan changed speed etc… Alan invited students to come up and play with it – they were really engaged with this part of the demo. Whilst this was harder to make accessible for the visually impaired student, some effort was still made to ensure that we were clearly describing what was happening in the box. In future if we were to run this demonstration with anyone who is visually impaired, we have a few idea for how to improve their access. We could have a second ultrasonic generator that sits outside the tornado box, that the student(s) could place their hands above and feel the mist when the generator is turned on. We could also build or 3D-print a small scale model of the tornado box and fix a small fan into the top of it – this would draw air into the box in the same way as the full scale version which the students could feel, which would aid in the explanation of what the sighted students can see.

Practical experiment – looking for voids using ultrasound

This experiment is a simplified version of one of our undergraduate physics lab experiments. Students are provided with some ultrasonic transducers which generate and detect ultrasound, a signal generator to power them, an oscilloscope to show the received signals, and some blocks of aluminium for the ultrasound the travel through. These blocks have holes (voids) drilled into them in various locations. When the students place the transducers on the blocks, they see a signal on the oscilloscope – the form of this signal depends on whether the transducer is positioned over a void or not, and hence the students can “see” where these voids are as they move the transducers over the top surface of the block. We’ve run this experiment for outreach events very successfully several times, as it provides a good mix between some hands-on experiments that are fun for the students and a good opportunity to discuss the physics of what is happening. Like the Chladni plate demonstration, however, this is very visual as the students need to see the oscilloscope screen to observe the changes in the received signal. The transducers are also quite small and can be fiddly to position correctly.

We planned for two different adaptations to this experiment. Martha wrote a script in LabVIEW that converted the signals received by the oscilloscope into audible sounds – like a parking sensor on a car. Additional “pings” would appear when the transducer passed above a void, and the pings would change pitch as the signal changed amplitude. This allowed the visually impaired student to find the voids in the block in the same way as any of the sighted students, giving them equity of access (which was a key goal of the day). We also wanted to anticipate the needs of any students who may have issues with dexterity or grip strength, as the transducers can be fiddly to use. This wasn’t a need that was explicitly communicated to us before the event but we thought it important to plan for this in case it was needed. Joe designed and 3D-printed some grips for the transducers that allowed the students to position and manoeuvre them with an open-hand grip and helped to keep them flat to the surface of the blocks. Both of these adaptations were so successful that we have been asked to help integrate them into the 2^nd year undergraduate labs for use by all students.

General Access Requirements

The day before the outreach event we had a meeting to discuss the various requirements that were communicated from the school. We made sure that everyone there on the day knew where the disabled and changing spaces toilets are, and planned approximate timings for the next day. We left plenty of time for moving everyone around at either end of the session, including thinking about how many people could fit in the lift at a time – in our case it was just one, so lots of time was reserved for this. Parking for the minibus was organised as close as possible to the entrance that they would be using. At the school’s request we also provided photos of the building, the space they would be working in, and the routes to and from this space including lifts and access to the toilets. We also provided a link to the interactive campus map so that the students could plan their visit and visualise their routes ahead of their visit.

What went really well?

The entire event went incredibly smoothly given the relatively complex requirements. The students seemed to be having a lot of fun, the teachers really helped us out by asking questions, linking into what they’d been learning at school, and encouraging students to get involved with the demos. The students were very aware that we had gone to some effort to make the day accessible for them, and were vocal about this during the session. We think everyone involved (students, teachers and demonstrators) found it very rewarding.

The key seemed to be that we had thought about how the students were going to interact with each part of the day and what the difficulties might be, and tried as best we could to create equity of access. At the same time, it was important that the event was not too structured and that we could be flexible with timings and activities based on how it was received by the students.

Did anything go wrong on the day, and what was done to sort it?

Not that we are aware of – a couple of students left the room during the Chladni plate demo, but there were enough teachers that someone could go with them, and it was expected that this might happen.

What was the feedback from the school?

• The impression was that everyone had fun. The teachers seemed to think it went well too. Feedback was received from the school after the event:
• Pupils overall really enjoyed the workshops and found them very interactive.One of their favourite demonstrations was the wind generator.
• All staff at the University of Warwick were very friendly and accommodating.
• Other positive words used by pupils were "informative" and "useful" with regards to the content.
• Our visually impaired pupil, really appreciated the resources prepared, and found the 3D printed models in particular helped her to access the workshop better.
• The pupils also really enjoyed the "bonus" tour they had of some other labs and areas of the university.
• One pupil even really approved of the quality of your ear defenders!
• In terms of what they felt could have been improved, they enjoyed the task involving using ultrasound to identify cracks and holes, and would've liked an opportunity to investigate more than one type of object, if this would be possible.Or use ultrasound in a slightly different context.
• A few pupils commented that they were intrigued to see more things related to astronomy.
• And lastly, very much with tongue-in-cheek, one of our pupils has criticised the name of the University - he has taken exception to the fact that it is not actually in Warwick!

Considerations for next event

During the morning the teacher mentioned repeating this for Year 10 where there are students who may require a quiet space. We did speak to the teacher and the astrophysics computer lab was a space identified to be used for this. There was a student who was upset at one point and it would have been good to have a sign on the door for this to be a quiet space for teachers and students.

We also took the students out onto the concourse to show them more of the university. This was optional as many asked to see more of the space while others wanted to stay in the lab with the plates. Next time we would plan more spaces to show the students.

The ultrasound experiment is being updated, to make it more accessible but giving the same equipment to all students so that no-one feels singled out.

Has this changed practice for outreach, lab teaching etc.?

This has been a really valuable exercise for our general outreach and lab teaching provision, and has shown clearly that improving accessibility helps not only those with additional needs but in fact helps everyone. The transducer grips and the audible signal for inspecting the aluminium blocks are likely to be integrated into the 2^nd year undergraduate labs as they make this experiment less fiddly to perform and make it more engaging – there is also the bonus that the lab will have built-in accessibility for any undergraduates with dexterity or sight issues.

For the Chladni plate demo we now have a set of 30 pairs of ear defenders which we will be using for all future demonstrations, and we have retained the 3D prints. These prints aid in explaining why we see the patterns in the salt, but also provide a more accurate picture of the shapes the plates make so have made this demonstration more complete. Additionally they provide a good jumping off point to discuss the job of a scientist – specifically how we might combine mathematical/computational models and experimental evidence when testing a hypothesis. This is often something we discuss with students at outreach events.

Is there any advice you’d give to someone who was considering a similar event or working towards accessible outreach?

For an event like this one, there are a lot of varied access requirements but they are known, so it is easier to think about what is required. Running outreach events like this one helped to make our experiments more accessible in general, since we now have all of these modifications if we ever need them during another event. For an event like the one we run, I’d recommend:

• Request a list of special access needs (where these can be disclosed). For example this may include dexterity issues, noise sensitivities, wheelchair access, special toilets etc. The teachers or carers who can provide this information are also often best placed to inform how these needs can be met – so ask them!
• Go through your list of proposed activities and consider each of the access needs – is it still going to be engaging for that student? Will they have any additional difficulty with an activity?
• Do what you can to create equity of access for those students. Our experience was that even if a solution is not perfect, they really appreciate that you’ve gone to the effort to help them get involved. Each event is also an opportunity to learn and improve the provision for next time.
• Have options: remember that you can talk to the students on the day and ask them what they would prefer – you don’t need to guess! In our case, we didn’t know before the day whether people would be okay with going in the small lift on their own. So, we had an accessible route planned to the much larger goods lift in case anyone wanted to use it. It turned out that nobody used it, but at least the option was there in case there was a problem.
• It is important to consider the agency of students and where possible give them options to compete tasks in the way that is most comfortable or appropriate for them – this goes for both their access to the experiments/demos and things like getting into and out of the labs.
• Make sure everyone knows where facilities are such as disabled toilets, quiet spaces etc.
• Plan how people will get to your location – we chose to meet them outside and bring them in along a pre-planned route where we had ensured the doors were sufficiently wide etc. Some students may benefit from having this information in advance.
• Get someone involved who does outreach regularly if possible – Ally thought of things that I wouldn’t have, and these really helped everything go smoothly.