I’m A Scientist Get Me Out Of Here – my answers: How do you find the right equipment to do an experiment?

I’ve been taking part in “I’m A Scientist Get Me Out Of Here” as a scientist, in the Pink Zone – answering schoolkids’ questions about science and other bits and pieces too.

How do you find the right equipment to do an experiment?

From my own experience it’s been fairly unusual to start a new experiment or research project without most, if not all, of the equipment you’d need already in place. Most (lab-based) experiments tend to build on previous work. Sometimes you might need a bit of equipment that’s slightly different – improved in some way: eg it can handle more samples per minute, or it does something faster, or it can measure even tinier amounts (or uses less energy, or even the spare parts just cost less!). Sometimes there’s a completely new and better way of doing something and a lab will need (and want) to get some whizzy new bit of kit – perhaps even ‘bespoke’ (where very few are made and they’re for a very specific purpose).

If a scientist hasn’t used a particular bit of equipment before then there are lots of things that can help them decide if it’ll be useful to them. Other scientists will have published their work (‘papers’) in scientific journals and those papers will say what equipment they used and how they did used it – so a scientist wanting to find out more may be able to get the information they need just by reading the literature. If not they can contact the scientists who wrote the paper and ask for advice. There are also lots of online communities (email mailing lists, social media) where scientists can talk about techniques and equipment and share improvements to the method that they’ve developed.

When I worked in labs I used some fancy equipment (eg a gas chromatograph – which separates a complex mixture into its components, and a mass spectrometer – which measures how much there is of each component) but I also used some fairly ordinary equipment like computers and things like pH meters (which tell you if your solution is just right… or too acid, or too alkali) but they were already there in the lab. In fact I went to work in those labs because I needed to access that sort of equipment (mass spectrometer), which is another way of finding the right equipment, moving to where it is! We also had amazing lab technicians who could create new bits and pieces of equipment (and replace broken ones, oops!) that we might need too.

So the equipment you’d need will depend on the type of science you’re doing and where you’re doing it (might not even be in a lab) and also and your budget.

There’s also a very literal answer to your ‘how do you find’ the equipment which is that there are catalogues (big thick books, or online versions) of scientific apparatus and equipment and people working in labs can order what they need. Here’s a very old one – “A catalogue of scientific instruments”, from 1916 https://archive.org/details/catalogueofscien00lekn/mode/2up (you can use the arrow keys to zip back and forth inside the book).

Jo

I’m A Scientist Get Me Out Of Here – my answers: What would it look like inside DNA?

I’ve been taking part in the Pink Zone (general science) for March’s “I’m A Scientist Get Me Out Of Here” aka #IASUK or #imascientist and I’m having lots of fun answering schoolkids’ questions about anything to do with science. There are two ways for them to ask questions: (1) there are live-text chats that they take part in with their classmates and chat to a handful of scientists and (2) they can post questions on the site and direct them to one or more of the scientists.

I’m gradually adding to this blog some of the questions from (2) that I’ve answered so far. I’ve redacted the names though they’re not particularly secret on the site (just first names or handles).

This was my first reply and I think I went to town a bit on it – could probably be shorter 😉

1. What would it look like inside DNA?
Hi [name redacted]

(The numbers in [square brackets] match a link at the end, in ‘References’, in case you want to find out more).

I agree with Enrico and Chris – you probably wouldn’t see very much if you shrank yourself to the size of DNA. Even if you could get inside DNA it would be a little bit like being inside a ladder that’s twisted around to form a spiral (or ‘helix’). There’s a drawing at the top of this article [1] which suggests what it might look like if someone could climb up the ‘ladder’ of DNA (not actually possible!). At the top of this page another drawing shows the shape of DNA’s helical (spiral) structure and also shows why we call DNA a ‘double helix’ [2].

If you were inside the DNA ‘ladder’ you probably wouldn’t be able to see very far in any direction (assuming there’s even enough light to see). It’s much easier to get DNA out of the cell and have a look at it that way. In fact you can do this yourself at home with some soft fruit, like strawberries, some detergent (liquid soap like shampoo) and some alcohol (ask a parent or guardian), like vodka or methylated spirits.

GETTING SOME DNA
There are many YouTube videos which show you what you need and how to do it (the recipe, or ‘protocol’). Here’s a video using strawberries [3] and here’s a step-by-step guide from BBC Science Focus [4]. You’ll end up with some white gloopy DNA that looks a bit slimy.

ZOOMING IN
Although you wouldn’t see that much if you looked at the DNA under a light microscope (you’d just see gooey strands) you’d see more if you used X-rays, which let you zoom in a lot more. This is probably the closest thing to shrinking yourself to climb ‘inside’ DNA. But you wouldn’t be looking *at* the DNA itself, you’d be looking at a pattern created by ‘shining’ a beam of X-rays through it.

Photo 51 is an X-ray photograph (taken in 1952) that shows the pattern produced when X-rays pass through DNA [5]. That photograph helped scientists learn a great deal about DNA’s structure. Steve Mould has a really good video [6] which shows how to recreate a version of historic Photo 51 using a lightbulb filament and a small laser – and how you can work out, from the patterns produced, what something’s shape and measurements are likely to be.

The DNA you’d see from the first video with strawberries is a bit like looking at a whole forest, the X-rays are like zooming in on a tree.

Jo

REFERENCES
[1] https://www.nature.com/articles/d41586-019-01176-9 – “The forgotten scientists who paved the way to the double helix”
[2] https://www2.le.ac.uk/projects/vgec/schoolsandcolleges/topics/dnageneschromosomes – “DNA, genes and chromosomes”
[3] https://www.youtube.com/watch?v=JofXXyFZn38 – “DIY Science: How to Extract DNA from a Strawberry – University of Leicester”
[4] https://www.sciencefocus.com/science/how-to-extract-dna-in-your-kitchen/ – “How to extract DNA in your kitchen”
[5] https://www.bbc.co.uk/news/health-18041884 – “The most important photo ever taken?”, about Photo 51
[6] https://www.youtube.com/watch?v=dqMYWldfs_k – “Shining a laser through a light bulb can reveal the structure of DNA” (always be careful with lasers, they can damage your eyes).

For a bit more on the size difference between visible light and X-rays see BBC Bitesize’s page on the Electromagnetic Spectrum https://www.bbc.co.uk/bitesize/guides/zw4tyrd/revision/2