Creating a custom science-themed laptop skin!

As an experimental particle physicist, my laptop is an extension of myself. I use it every day to work, to run my code, to talk to colleagues around the world, to check Twitter, and also to relax. I’m writing this post on it right now!

Since I (usually) travel a lot, it’s a vital way that I can continue working on the road, or during a global pandemic.

Recently, I decided it needed decorating. I spent ages looking on a website that sold stickers for laptops for one that really resonated with me. I would be looking at this images for potentially years, I wanted it to be something I liked. In addition, people at work would be looking at it too (when we can finally leave our houses again), so it had to be something professionally appropriate too.

In the end I couldn’t decide on one image, so I decided to cover my laptop with many using a custom design! Here’s the result:

If you look closely, there are photos of the Large Hadron Collider, the four major detectors on the LHC (with a bias towards ATLAS, because that’s the one I’ve worked on for the last 10 years +) and other photos from around the CERN site, including the most famous one I’ve ever taken which is of a dishwasher!

If you want to make one of these yourself, here are the steps I took. Feel free to diverge at any point.

  1. Find out the size of your laptop in inches (sorry, metric-fans!). Most printers will want an image ‘resolution’ of 300 DPI, which means Dots Per Inch from the printer. To get this, you should multiply the length and width of your laptop in inches by 300 each and that’s the number of pixels your canvas size should be. For example, I have a MacBook Pro with a 15″ screen, so I needed 4140x2860px.
  2. Now that you have your canvas size, you need to pick your image. You could use one single large image (but you’ll want to make sure the resolution is high enough). Or, if like me you couldn’t pick just one, you need to plan out the multiple photos and how they will fit together. Please make sure that you have the right to use the images you want to include. For my design I either used photos I had taken myself (or asked someone to take for me on my own camera), or I used images from CERN which are free to use providing you’re not going to sell them or use them inappropriately. Please check out the CERN Terms of Use before going ahead.
  3. Next, you want to put your image(s) into your canvas. For this, I use the free version of Canva, which allows you to pick your canvas size, upload your images and fit them to a grid of your choosing. If you’ve never used Canva before and you click the link above, then we’ll both get a credit to put towards premium content after you’ve made your first design. If you don’t want to do that, then go to directly :).
    Don’t forget to edit your images if you want to. I made all mine monochrome.
  4. Find a place to print your design! I used GelaSkins to print my design. Look for the ‘Create your own’ tab on their website. I messaged them beforehand to talk about what I wanted, and they discussed my order with me at every stage. They do ship from Canada, though, so if this is far from where you live, you’ll need to add in that there’ll be a higher delivery cost and time taken for the skin (as they call it) to arrive.
    (Note: I am not being paid to tell you about them, I was just very happy with how it turned out!)
    If you don’t feel creative yourself, they have a wonderful collection of art you could use instead. I had Vincent van Gogh’s Almond Blossoms on two of my previous laptops.
  5. Finally, wait for your design to arrive (shipping may take longer at the moment) and fit it onto your laptop. You’re on your own with that one though!

And that’s it! You don’t even have to stop at your laptop, you can cover your phone, tablet and more!

If you do make one, please feel free to share it with me below, or on Twitter or Instagram. I’d love to see your creations!

Recreating the nails in the box video

There’s a video going around social media of a box of nails getting sorted by shaking. I was sceptical about whether this was a real video, or reversed, so as a good scientist, I decided to recreate the experiment for myself! Here are the results:

What do you think? Do you believe it? Have you also tried it at home? Let me know in the comments below!

Thanks to Irene for the collaboration in getting the equipment and testing out this hypothesis.

On Call for the ATLAS experiment

This weekend I was on call for the @atlasexperiment, specifically for our control room shifts monitoring the Inner Detector.

What does that mean?

It means I left my weekend free to be called if someone who was scheduled to be on shift during this time gets sick, injured, or is otherwise unavailable. It wasn’t likely that I’d be called, but it’s important to know someone qualified is free if needed.

On Saturday, I went to our control room to check how everything was going, and to pick up the phone I can be called on. Since it was a beautiful and sunny day, I went for a walk around our Globe of Science and Innovation here at CERN.

By the Globe, is this statue, covered in equations, diagrams and the names of historical scientists whose work has been influential to the research taking place at CERN.

This area is open to walk around on weekdays and on Saturdays at the weekend. So next time you’re in Geneva, Switzerland, why not come and check it out! And if you plan ahead, you can also book a tour of CERN!

The Great North Run and Mermaids

I am thrilled to announce that in September, I will be running the Great North Run for Mermaids!

Me running the Paris Marathon. This is the best photo of me running I have. Thanks Julien Villa-Massone! (Note: image has been edited to remove the logo on the t-shirt).

Every young person deserves to grow up in an environment where they can be their true selves. I am supporting Mermaids because of the vital work they do to make this a reality for young gender-diverse people in the UK.

Unfortunately there is a large hate campaign against the trans and non-binary community and this can only be increasing the anxiety that young gender-diverse people are experiencing. Let’s be a light shining through that hate and show that we are here for them.

To help persuade you to part with your hard-earned cash, I will be live-streaming during some of my training runs later in the year to talk about how the training is going, why I’m running for Mermaids & some science facts too!

You can check out my fundraising page, here:

Shaking off the dust

Hello! It’s been a while. I let this website slip and stopped posting and honestly I don’t remember why. However, the longer it had been since I’d last posted the more I felt like I needed to have something especially good to post when I came back.

But as they say, perfection is the enemy of good. So, instead, I’m shaking off the dust. I’ll try to get back to posting regularly and we’ll see how that goes. A lot has changed since I was posting last. And a lot is still the same. Looking forward to sharing it with you.

Bye for now! Clara

A beautiful hotel courtyard in Puebla, Mexico. Photo: C. Nellist 2019

The trial and error of time-lapse videos

As an experimental scientist my job is all about trial and error. I take measurements that no one has ever taken before, so I don’t know the results in advance. Although I usually have an idea (or hope) what the outcome will be, sometimes we can be surprised. To get the results, I start by trying one approach and, if it doesn’t go well, I learn from that and make improvements for the next time. This is the basis of the scientific method.

Screen Shot 2016-06-24 at 16.52.27

So when I decided I wanted to take more time-lapse videos, naturally for me I took the same approach. In this post, I’m going to show you some of the mistakes I’ve made along the way. Just as it is at during my research, these errors are valuable learning experiences and also part of the fun!


For information, the videos have all been made with a Go Pro 4 Black. I’ve added to my equipment along the way, usually as a result of learning from a video.

Note: All links in the main body of this post are to Amazon and are affiliated links. If you’d prefer non-affiliated, you can click the links at the bottom of the post.

#1 Securely attaching the camera

My camera was pretty new when I was volunteering for the TEDxCERN event in 2015, so I was keen to find out what I could do with it! I thought it would be a nice idea to film the guests arriving for the start. I didn’t have a lot of extra equipment, except for a 3-way tripod, so I ended up using scotch tape to to secure the tripod to a bar just above head-height. Unfortunately, it wasn’t secure enough and when I came back to check on the camera after some time, it was pointing towards the ground!

#2 Having a long enough battery life

I quickly learnt on my trip to Asia that the camera only had a battery life of ~2 hours and so leaving it on overnight wasn’t going to give me that sunrise video I was after! The problem with the standard Go Pro case is that it doesn’t have any access for the power cable, so the camera can’t be charged while it’s in the case and on a tripod. I looked, while I was travelling, for a skeleton case that would give access to this port, but I wasn’t able to find one in any shop (even at airports). Instead I had to start the camera less than two hours before the event I wanted to record.

View of the Royal Palace, Phnom Penh, Cambodia.

Later, when I returned back to Europe, I was able to find a frame which allowed me access to the charging port. Now I use this case with my portable charger, which means that I don’t need to be next to a plug to take videos. I use a 16,000 mAh external charger which, when close to fully charged near the beginning, has always been more than enough for leaving the Go Pro running overnight.

Another mistake I made with this video is setting the interval for the photo at 4 minutes, so I had very few frames to make a video from. Definitely set it to fewer. The maximum I use now is 10 seconds per photo.

#3 Keeping the camera still

During a trip to Vietnam last year, I was very fortunate to get an upgrade on my overnight boat trip in Ha Long Bay, which meant I had a private deck space! This was a great opportunity to capture a video of a sunrise in this stunning location. I setup the camera on the tripod and securely (very securely!!) tied it with shoe laces and a travel-washing line to to the railings of the boat. Around sunrise, I woke up and went outside to turn the camera on with the time-lapse setting. I then went to have breakfast on the top deck with the rest of the guests.

Later in the morning I looked back at the footage and realised something that should have been completely obvious to me – boats move. I’m not just talking about bobbing up and down in the water, although that is a problem, but they also drift with the current around the anchor and, when the crew wake up earlier than you do, they move on to their next location while all the guests are still sleeping or having breakfast. All of these movements provide a challenge when trying to have an interesting video that isn’t going to make everyone seasick! Below is what I managed to get with this. Looking back on it now, I’ve grown fond of it, but it wasn’t the video I intended to take.

Having the right equipment

I visited Japan for work in March and had the weekend before as a tourist in Tokyo. I went to visit Shibuya Crossing, which is famous for being the busiest crossing in the world! I had recently bought a rotating egg-timer like device to pan the camera as it recorded, so I was looking forward to using that. I thought it came with two screw-to-GoPro adapters, but it didn’t, so when I came to build the setup, I didn’t have all the right pieces. In the end, I taped most of it together and hoped it stayed long enough to get a good video.

When I returned, I ended up buying a 40-in-1 (37 in the US, not sure why) kit, which had the GoPro tripod adapters that I wanted, plus much more.

A tripod

The following video was taken of the Notre Dame Cathedral in Paris. Unfortuantely without a proper tripod, I had to rest the Rotating Time Lapse Timer on a step, which meant the camera was among the legs of the tourists passing by.

After this recording, I decided to buy a proper tripod. In the end I went for a Manfrotto Befree Compact Lightweight Travel Tripod, because it folds up really small and is very lightweight (it’s in the name!). 

Having a clear view (AKA cleaning the window!)

On a visit to see family in Saltburn in the UK, I stayed in a hotel room with my siblings. The view of the ocean was beautiful and I worked out that the sun would rise directly over the water! I decided to try to capture the sunrise. While I was setting up the equipment, I noticed that the window wasn’t brilliantly clean, but I couldn’t get my arm out to clean it. It didn’t seem too noticeable, so I set the camera running when I went to sleep and came back the next morning.

Unfortunately, when the sun hits at certain angles, the marks on the window show up noticeably. Take a look below.

Having an interesting video

The next time I visited Saltburn, the weather was very foggy. Feeling optimistic, I setup the camera and hoped that the fog would clear during sunset, making a dramatic video. It didn’t. Below is the result of this attempt, which I wouldn’t say was the most interesting time-lapse video.

Being aware of the weather

This lesson is linked to #1, securely attaching the camera. In this case I wanted to take a 360 degree time-lapse of Luxembourg Park in Paris. It had been sunnier in the day, but it become overcast later. I was still determined, and clouds make interesting additions to the videos. However, this also meant wind and rain.

Take 1. I set up the camera on my full-sized tripod and put this on a bench. After ten minutes or so, I turned to look at the camera and as I did I saw it suddenly coming towards me! Fortunately I caught the tripod as it fell from the bench, but because of the wind, I had to move it to the ground. This meant I didn’t get as good of a view over everyone’s head, but it was better than the camera landing on mine!

Take 2. I started the camera again. After another roughly ten minutes a sudden downpour started and I quickly thew the tripod case over the camera to protect it. But this was the end of that take!

Take 3. Since it was getting late in the afternoon and I wanted to eat at some point, I had to abandon my plan of a full 360 degree video and instead settle on a ~150 degree video. This time the wind was not too strong and the rain (mostly!) held off, so I got the video I wanted. You can see I also edited the colour on the final video to give contrast to the clouds and bring out the colour of the senate building.


So that’s where I’m up to now. I’m sure there will be many more lessons to learn as I go along. Perhaps even enough for a second post. The next thing I want to work on is getting rid of glare and reflections from windows when I have to film in doors. For that I’m going to try a dark cloth taped around the camera.

For now, I’ll leave you with a video I took in Cambodia at an elephant sanctuary of the elephants taking their morning bath. Enjoy!

If you want to check out all my videos, you can visit my YouTube Channel. If you like them, please give them a thumbs up and maybe even subscribe. Thanks!

Non-affiliated links (all link to the UK Amazon store):

Sept, 2019: This post was edited to remove the affiliated links because I no longer use that service.

Test Beams

The last ten days or so I’ve spent at CERN testing new designs of pixel detectors for the ATLAS experiment. Since it was the IOP’s #iamaphysicist event on the same day we were setting up, I tweeted out the following picture.

To measure our pixel detectors, we need a beam of particles from a particle accelerator. Fortunately at CERN, we have many to chose from! Just see the diagram of all of the accelerators required to get the protons to the LHC. Our experiment uses the SPS, or Super Proton Synchrotron, the last accelerator in the chain of accelerators which feed the LHC with protons. The protons enter the SPS at 25 GeV and are accelerated up to 450 GeV (note the LHC accelerates to 7500 GeV, or 7.5 TeV, per beam). We then use a target to change the type of particle from a proton to a pion.

The LHC is the last ring (dark grey line) in a complex chain of particle accelerators. The smaller machines are used in a chain to help boost the particles to their final energies and provide beams to a whole set of smaller experiments, which also aim to uncover the mysteries of the Universe.

Continue reading Test Beams

Taking pictures of particles and other stories from a high energy physicist