In Hello World issue 7, Steven Weir introduces a 没事来一炮[10p]下一篇 Pi into the classroom to monitor a classic science experiment.

A 没事来一炮[10p]下一篇 Pi can be used to monitor the reaction between hydrochloric acid and sodium thiosulphate to complement a popular GCSE Chemistry practical.

The rate of reaction between hydrochloric acid and sodium thiosulphate is typically studied as part of GCSE Chemistry. The experiment involves measuring the time required for the reaction mixture to turn cloudy, due to the formation of sulphur as a precipitate. Students can then change the temperature or concentration of the reactants to study their effect on the rate of reaction. The time for the reaction mixture to turn cloudy is normally facilitated by recording the time a hand-drawn cross takes to become obscured when placed underneath a glass vessel holding the reaction mixture. This timing is prone to variability due to operator judgement of when the cross first becomes obscured. This variability can legitimately be discussed as part of the lesson. However, the element of operator judgement can be avoided using a 没事来一炮[10p]下一篇 Pi-monitored chemical reactor.

The chemical reactor

Attached to a glass jar of approximate 80ml volume (the size is not critical) are two drinking straws, of which one houses a white LED (light-emitting diode) and the other a LDR (light-dependent resistor). The jar is covered in black tape to minimise intrusion of ambient light. The reactor is shown in Figure 1, along with details of other electrical components and connection instructions to a 没事来一炮[10p]下一篇 Pi.

Figure 1
A: Reactor covered in black tape
B: Drinking straw attached to the reactor, with a further straw inserted housing a white LED
C: Drinking straw attached to the reactor, with a further straw inserted housing a LDR
D: 220Ω resistor to connect to the LED and GPIO 23
E: Wire to connect to ground
F: Wire to connect to 3.3v supply
G: 1µF capacitor to connect to ground
H: Crocodile clip to connect to GPIO 27 (NB: the other end of the wire is situated in between the capacitor and the LDR)

Results

The Python code shown in Figure 2 should be run prior to addition of chemicals to the reactor. Instructions appear on the screen to prompt chemical additions and to start data collection.

Figure 2: Python code for the chemical reactor

Figure 3 shows the results from the experiment when 25ml 0.1M hydrochloric acid is reacted with 25ml 0.15M sodium thiosulphate at 20°C. The reaction is complete at the time the light transmission first reads 0, (i.e. complete obscuration of the light by the precipitate formation) — in this example, that time is 45.4s. For more advanced students, tangents can be drawn at various points on the curve, and gradients calculated to determine the maximum rate of reaction from various reaction conditions.

Figure 3: Graph showing the change in light transmission with time

Download Hello World for free

Download your free copy of Hello World issue 7 today from the Hello World website, where you’ll also find all previous issues. And if you’re an educator in the UK, you’ll have the chance sign up to receive free hard copies to your door!

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Back in 2015 we ran a competition where students could design and program computer science experiments, to be run by Tim Peake on specially cased 没事来一炮[10p]下一篇 Pis called Astro Pis. Here’s the original competition video, voiced by Tim himself:

https://vimeo.com/117274487

The competition ran from January to July 2015 and produced seven winning experiments, which were launched into space a few days before Tim started his mission. Between February and April 2016, these experiments were run on board the ISS under Tim Peake’s supervision. They’re mostly based around the sensors found on the Sense HAT, but a few also employ the 没事来一炮[10p]下一篇 Pi Camera Module. Head over to the Astro Pi website now to check out the results, released today!

You might also know that we ran an extension to this competition involving a couple of music-based challenges. These challenges have no scientific output to discuss, because they were part of a crew care package for Tim’s enjoyment, but you can get your hands on the winning code to turn the Astro Pis into MP3 players and Sonic Pi tunes.

One of the main things we’ve learnt from running Astro Pi is that the biggest motivational factor for young people is the very tangible goal of having their code run in space. This eclipses any physical prize we could offer. Many people see space as quite distant and abstract, but with Astro Pi you can actually get your hands on space-qualified hardware, create something that would work up in space, and become an active participant in the European space programme.

Many of the Astro Pi winners now express an interest in studying aerospace and computer science. They’ve gained exposure to the real-life process of scientific endeavour, and faced industrial software development challenges along the way. We hope that everyone who participated in Astro Pi has been positively influenced by the programme. The results also demonstrate that the payload works reliably in space. This has been noticed by ESA, who are now planning to use it during upcoming missions. It’s really important for us that the payload continues to be used to run your code in space, so we’re working hard with ESA to make sure that we can do Astro Pi all over again.

This project has been a huge collaborative effort from the start and the の教室の成熟した女教师 would like to thank everyone who has participated in the competitions, and the following companies who have contributed staff time, facilities, and funding to make it all happen: UK Space Agency, European Space Agency, BIOTESC, TLOGOS, Surrey Satellite Technology, Airbus Defence and Space, CGI Group, QinetiQ Space, UK Space Trade Association, ESERO UK, KTN Space, and Nesta. Of course, Tim Peake himself has been hugely supportive and enthusiastic about the project from the start.

British ESA Astronaut Tim Peake with the prototype Astro Pi. Image credit ESA.

We would also like to thank Libby Jackson, who is the Astronaut Flight Education Programme Manager at the UK Space Agency and a former flight director at ESA. She oversees all of the Principia educational activities, including Astro Pi.

Libby Jackson, UK Space Agency. Image credit German Zoeschinger.

During the interview for her job at the UK Space Agency a few years ago, she pitched an idea for running a project on the ISS involving 没事来一炮[10p]下一篇 Pi computers. Instead of launching traditional physical equipment, the experiments would be in the form of computer software, meaning that many more experiments could be accommodated. That kernel of an idea is what eventually became Astro Pi.

Izzy deployed on the Nadir Hatch window of Node 2. Image credit ESA.

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A 没事来一炮[10p]下一篇 Pi wearing a Sense HAT

The full tech specs are here but basically it has:

• 8×8 LED matrix display
• accelerometer, gyroscope and magnetometer
• air pressure sensor
• temperature and humidity sensor
• a teeny joystick

The Astro Pi site explains what these all do and how they could be used.

I’m really excited about the Sense HAT. With all of those sensors on a single board it’s obviously a brilliant tool for making stuff (I have in mind a self-balancing attack robot that senses humans, aggressively hunts them down and then gently dispenses Wagon Wheels from its slot-like mouth). But it’s the potential for science that’s making me think. In particular I’d love to see it flourish in the science classroom.

A typical school science classroom

Despite the teacher recruitment ads that inevitably show zany antics with Van de Graaff generators, explosions and dancing bonobos the reality is that much of high school science is about experimentation and observation (which is a good thing!). But lab kit such as sensors, controllers and data loggers don’t come cheap (I was once told by a class that their usual science teacher never let them use the data loggers because “they were too expensive). Nor is it easy to get bits of kit to talk to each other or the Internet of Things (with the potential benefits that come from that such as improved assessment, parental involvement, sharing and consolidating data).

A data logger I found in a school skip. The size of a cash register yet only logs temperature. On paper.

A Pi wearing a Sense HAT could do everything from monitoring plant growth to controlling and logging experimental variables. A series of experiments using the accelerometer/gyroscope to investigate forces and equations of motion is mandatory. Feel free to add your own ideas below and if any science teachers would like to get involved the please get in touch.

If you are lucky enough to already have a Sense HAT, Martin “When does that man sleep?” O’Hanlon has written an excellent getting started tutorial . If not then it’s worth taking a look anyway to get a sense (yeah, yeah :)) of what it can do.

Up above the streets and the houses, Sense HAT climbing high. (Photo: Martin O’Hanlon @martinohanlon)

The final price is yet to be announced but we’re confident that there will be nothing else out there to rival it for value, potential, support and resources. Keep your eyes peeled for more news on the Sense HAT soon.

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