What does a black labrador have to do with medical imaging? Nothing, you might think… but in fact he is a rather helpful ingredient in a lovely analogy to explain why contrast agents are useful in imaging.
The dog is easy to see in the daytime but rather hard to see at night – demonstrating why doctors need contrast agents to make certain cells or body parts show up on scans (and why the hound of the Baskervilles was coated in glowing phosphorus for a more spooky effect).
This great example of a science analogy comes from a lovely website set up by Martin Christlieb at the Gray Institute for Radiation Oncology and Biology, which I discovered this week. And it reminded me to write down some of my favourite science analogies so I don’t forget them. Here are a few I really like…
1. Drug substances and drug products = sugar and sweeties
I don’t think I could have explained this at all until recently, when I was given a demo I’m definitely going to steal. The drug substance is the ‘active ingredient’, while the drug product is the pill, injection, cream, or whatever you actually use to get the drug into the body. For a simple example, imagine a sachet of sugar. That’s your drug substance – while a more colourful and exciting pack of sweets is the drug product. Eating the sweets really helped this stick in my mind…
2. Epigenetics = highlighted or annotated passages in a book
I’ve had some arguments about this one, but I think it’s really helpful. Epigenetics is SO HOT RIGHT NOW but for ages I found it pretty hard to grasp or explain. In this analogy, the book is the genetic code, and the highlights are ‘edits’ that don’t actually change (mutate) the words but can still affect how you ‘read’ the code. Even better, if you pass your book onto someone else, your highlights will still be there (they’re inherited!).
3. Ecdysis = growing out of your shoes
I like the word ecdysis but it’s not very helpful unless you’re a lot better at Greek than I am. It refers to the way some arthropods burst out of their hard exoskeletons as they grow. This analogy is a good one for explaining this process to kids – they all know what it’s like to grow out of a pair of shoes and need new ones. Crabs have the same problem – except they can grow their own ‘shoes’, which is pretty cool. And there’s an added bonus because it neatly explains why crabs and other arthropods can be very vulnerable in between moults – imagine running around all day with no shoes to protect your feet.
4. Drug development = solving a Rubik’s cube
This is an excellent analogy, turning a really complex problem into an image that everyone can relate to. We all know that feeling of twisting and turning the cube – every time one face is coming together, another is just getting messier, until you give up and throw it away in disgust. It’s exactly the same for researchers working on new drugs – solving one problem (like how soluble the drug is) tends to create three more (like making it less effective). And this one has a nice side effect of showing just how clever drug developers have to be to ‘solve the cube’.
5. Space-time = a flexible sheet
An old one but very helpful to the mathematically challenged like me. Space-time is a crazy concept, but picturing it as a flat sheet dented by the mass of objects like planets is surprisingly clear and intuitive.
The common theme with all of these examples is that they plant an image in your mind, helping you to get your head round a problem in one easy step. They also use concepts nearly everyone understands – making it easier to relate to the scientific problem.
Some scientists don’t like analogies because they often simplify the science they aim to explain, but usually this is no bad thing. You’ve got to start somewhere, and with a topic like epigenetics that starting point has to be fairly basic. And nothing beats that lightbulb moment when you see an analogy finally click in someone’s mind, making their eyes light up.
Now if only I can find an analogy that will help me understand Bayes’ theorem…