Myth-busting Monday: Bacon vs Cigarettes

Mondays are great for busting myths.

(They’re also great for going meat-free, which may seem even more appealing after reading this article.)

Today’s myth concerns the cancer-causing nature of processed meats, and how it compares to other well-known carcinogens.

Myth: Eating bacon is as bad for you as smoking cigarettes.

Truth: It is true that in October 2015, the World Health Organisation (WHO) released a report that confirmed a link between processed meats and cancer. Not only that, it placed processed meats such as bacon, frankfurts and salami in the Group 1 Carcinogens category, alongside cigarettes, asbestos, and radioactive metals.

This prompted a flood of articles with headlines along the lines of today’s myth – that eating processed meats was as bad for you as smoking cigarettes.

BUT…all carcinogens are not created equal. There is equally strong evidence that all Group 1 substances are carcinogenic, but that doesn’t mean they are all equally carcinogenic.

Confused? Maybe some stats will help.

The overall lifetime risk of getting bowel or colorectal cancer is about 6% – in other words, about 6% of the population will have one of these cancers at some time in their lives.

The WHO report found that each daily 50g portion of processed meat you eat increases your overall risk of these cancers by 18%. That is, if you eat 50 grams of bacon, ham, or salami every day, your risk increases to 7.08% (6 x 1.18). If you eat 100 grams of bacon every day, it increases to 8.35% (6 x 1.18 x 1.18), and so on.

These figures are for consistent daily consumption over your whole life – so the effect of an occasional BLT or hot dog on your cancer risk is minimal.

Smoking cigarettes, on the other hand, increases your overall cancer risk by a much higher percentage. The Cancer Council states that smoking 10 cigarettes a day DOUBLES your cancer risk, and smoking more than 25 a day doubles your risk again – that is, an increase of 400% on the overall risk (which is also around 5-6%).

Smoking is also implicated in 86% of lung cancer cases and 19% of all cancer cases – by comparison, daily consumption of processed meats is linked with 21% of bowel cancers and 3% of all cancers.

These numbers are certainly significant and should probably make bacon-lovers reconsider their consumption…but smoking is still far worse for your health overall.

Learn more

If you’d like to learn more about the specifics of the World Health Organisation report, visit their Q & A page on this topic.

For Australian-based advice on how to reduce your cancer risk by swapping to healthier alternatives in various areas, visit the Cancer Council website.

To read more about the cancer-linked ingredients in bacon, have a look at this article from The Guardian.

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Myth-busting Monday: Pouncing Pepper

You might have seen this viral (ahem) video doing the rounds – a preschool teacher is using the ‘pouncing pepper’ demonstration to show her students how soaps keep germs away.

Myth: The ‘pouncing pepper’ demonstration shows how soap repels germs from our hands.

Truth: Of course, anything that gets people washing their hands more often is definitely a winner (whether or not there’s a global pandemic). And pouncing pepper is a great demonstration of a scientific phenomenon, but perhaps not the one you might think…

You can do this demonstration at home using just a few materials. A cotton tip or finger is dipped into some water with pepper sprinkled on top, and gets covered with pepper. But when the finger-dip is repeated with detergent, the pepper instantly jumps away!

So does soap repel germs in the same way it appears to repel the pepper in this demonstration? No. In truth, pouncing pepper doesn’t actually demonstrate the effectiveness of soap in removing germs.

This experiment works because of water’s surface tension. Water likes to stick to itself, and surface tension is a bit like a skin formed by the water molecules at the surface. The pepper is small and light enough that the surface tension can support it. But something bigger or heavier, like a person, can break through. You’ll know all about this if you’ve ever bellyflopped into a pool!

So how does soap affect all this?

Soaps and detergents reduce the surface tension of water – this is part of what helps them clean away oils from our hands and dishes. But the germs don’t exactly leap away.

Bacteria and viruses are partially made up of fats, which are broken down by detergents – the detergent reduces the water’s surface tension, allowing it to get between the bits of oil. Detergent is also a long molecule with one end that attracts water, and the other attracts oils. This allows the oil to mix with the water, and be washed away as you rinse.

So back to our pepper experiment. When you touch the detergent to the surface, the surface tension is reduced in that one spot. It’s a similar effect to popping a balloon – if the tension is reduced in one spot, the higher tension everywhere else pulls back from that spot, making the ‘hole’ bigger. And the pepper just helps us to see how those water molecules at the surface are moving.

So this awesome experiment is a great demonstration of how soap changes the surface tension of water, but unfortunately, germs don’t leap away from soap like the pepper does. Which means you need to keep washing your hands! Properly! Go and do it now!

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Myth Busting Monday: Rainbow Shapes

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You can’t help but feel happy when you see a rainbow. They’ve been interpreted as divine messages, adopted as symbols of various causes and movements, and used to decorate just about anything you could imagine. So it might surprise you to learn that one of the most recognisable features of the rainbow is not actually as it seems…

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There is more to a rainbow than meets the eye. Image by Free-Photos from Pixabay.

Myth: A rainbow is a semi-circular arc

Truth: There is more to a rainbow than meets the eye. The semi-circular arc is simply the part of the rainbow we can see – the rest is usually obscured by the ground.

First things first – how does a rainbow form?

A rainbow forms when sunlight hits small drops of water in the air. Water is denser than air, so the light slows down and bends (refracts) a tiny amount when it enters the water drop. The light bounces around inside the raindrop, then exits again at a different angle.

As we know, white light is made up of lots of different colours (Red, Orange, Yellow, Green, Blue, Violet) which all have different wavelengths and therefore different amounts of energy. The colours with longer wavelengths (the ‘red’ end of the spectrum) bend less than the colours with shorter wavelengths (the ‘violet’ end). This is what causes the light beam to split into that recognisable spectrum of colours that is so familiar to us.

White light is separated into its component colours (red, orange, yellow, green, blue, violet) by a triangular prism
White light is separated into its component colours (red, orange, yellow, green, blue, violet) by a triangular prism. Image by Lucas V. Barbosa - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=3270145

Where can I see a rainbow?

The rainbow you see depends on where you are standing relative to the light and the raindrops. The sun has to be behind you, and the rainbow will form at an angle of 42 degrees from something called the ‘antisolar point’, which is roughly marked by the shadow of your head.

(In other words, if you drew a line from the shadow of your head to your eyeball, and another line from your eyeball to the rainbow, the angle between the lines would be 42 degrees.)

This means that if the sun is lower in the sky, the rainbow will appear higher, and vice versa.

Can I go to the end of the rainbow?

The rainbow’s position depends on your eyes’ position. This means that if you move slightly, so will the rainbow that you see. And someone standing next to you will see the rainbow in a slightly different position. And THAT means that it’s literally impossible to walk to the end of the rainbow. (Sorry.)

That’s a shame. Are you going to tell me what shape a rainbow is?

Of course. Consider that 42 degree angle you drew before, between your head shadow, your eye, and the rainbow. The water drops at the correct angle from your eye to form a rainbow aren’t just in one spot. They’re in an arc, all around your eye. ALL around, meaning that if you replaced the ground with a bunch more water droplets (or your vantage point was high enough), the rainbow you’d see would be a complete circle!

Mind. Blown.

A circular rainbow over the ocean
When viewed from a high enough vantage point, a rainbow will appear as a full circle. Photo by Jakob Owens from Stocksnap.

That’s amazing! But…there’s a but, isn’t there?

Yep. But…if you’re ready to have your mind blown even further, consider this.

Rain isn’t usually two-dimensional. It doesn’t just fall in a sheet and make a line on the ground. It’s three-dimensional – and so the rainbow-forming droplets also take up a three-dimensional space.

A rainbow therefore isn’t a fixed distance away from you, the observer – it can be anywhere there are droplets of water at the correct angle. If you are unlucky enough to be standing in a solid rainstorm with the sun shining behind you, there are rainbow-forming droplets everywhere from right next to your eyeballs, to several kilometres away.

So a rainbow isn’t just a two-dimensional circle…it’s actually a three-dimensional CONE. With your eyeballs at the point, and your head-shadow (the antisolar point) at the centre of the cone’s base.

Next time you see a rainbow, make sure you inform the nearest fellow observers that it is, in fact, a rainbow CONE.

And if you’ve managed to get your head around this, head on down to your nearest ice cream shop and treat yourself to a triple-scoop cone – you have certainly earnt it.

Rainbow swirl ice cream cone
Another slightly more delicious kind of rainbow cone. Photo by Key Notez from Pexels.

Need more detail? Here is a more in-depth look at the maths behind rainbows (external link).

Use your new-found rainbow knowledge to make your own rainbow at home.

Myth Busting Monday: Goldfish Memory

myth busting Monday - goldfish wearing a mortar board

Happy Myth Busting Monday! Ichthyophiles, it’s your day – today we dispel a tenacious myth about one of your favourite creatures…

Myth: Goldfish have a three-second memory

Truth: Goldfish, and most other fish officially studied, have been shown to have memories extending far past the three-second barrier. Fish intelligence, cognition and sentience has been studied extensively over the years, often using the classical conditioning techniques popularised by the scientist Ivan Pavlov and his many well-trained dogs. In one type of study, fish that were fed at one end of their tank in the morning, and the other end in the evening, started to gather at the correct ends in anticipation of feeding time. This showed that they could make associations between locations, times and rewards.

If you have your own fish, this type of study is very easy to replicate (and please let us know about it if you do!). In fact, in 2008 a 15-year-old student named Rory Stokes decided to debunk the goldfish memory myth for himself. He put a red Lego block into his fish tank each day and sprinkled the food around it. After just three weeks, Rory found that the fish would start to gather around the red Lego block before he had put the food in. He also found that the fish still associated the Lego with being fed even after a week of Lego-free meals.

It’s almost certainly a good thing that fish can remember things for more than three seconds. A memory this short would be of little to no use to a living creature that had to find itself food, avoid predators, and otherwise survive from day to day.

So where did the myth come from? It’s possible that it was invented by purveyors of pet fish, to make everyone feel better about keeping fish in small uninteresting environments. It’s also possible that pet fish’s repetitive behaviours were interpreted as the fish ‘forgetting’ what it had already done, although repetitive behaviour in a captive animal usually indicates that the animal is somehow distressed. So if you do have pet fish, keep their minds active by making sure that their tank is interesting and stimulating – it’s best to consult fish-keeping experts for the best ways to do this!

P.S. If you’re someone who regularly employs the ‘memory like a goldfish’ simile to describe someone’s (or your own) poor memory, might we suggest switching to ‘memory like a sieve’? Sieves have indeed been scientifically proven to let many things through them.

P.P.S. An ichthyophile is one who loves fish. #todayilearned

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Myth Busting Monday: Cars and Lightning

A giant Van der Graaff generator at the Boston Museum of Science creates lightning bolts, zapping a cage containing the show's presenter

It’s Myth Busting Monday again! Let’s zap this one once and for all…

Myth: Your car’s tyres will insulate and protect you in the event of a lightning strike.

Truth: Choosing to stay inside your car during a thunderstorm is usually the safest option – this much is true. But the protection the car offers has little to do with the tyres. In fact, it’s the car’s metal body that protects you!

“Huh? But metal conducts electricity…?”

Yep! The car’s protection comes from the fact that it is a hollow ‘cage’ made from an excellent conductor of electricity. Lightning is basically a stream of charged particles looking for the shortest path between a storm cloud and the ground. If its path happens to go via you, this is bad news. It’s generally not advisable to be outside in a thunderstorm, and especially not near something tall like a tree that is likely to attract the lightning (and send it via you).

But if lightning hits the top of a car, it will continue to travel through the metal body of the car AND the tyres (and safely around you) to the ground. This phenomenon was harnessed by Michael Faraday, who discovered that a continuous shield of conductive material would stop an electromagnetic field (including lightning and radio waves). He developed the Faraday cage in 1836 to protect electronic equipment from damage and interference.

Incredibly, a person inside a Faraday cage can even touch the metal on the inside of the cage while lightning is striking, and remain unharmed (NB. DO NOT TRY THIS PLS). This is demonstrated in one of the best science shows we’ve ever seen, at the Museum of Science in Boston, MA, back in 2012. The presenter stands inside the cage, nonchalantly running their hands around the metal bars, while the world’s largest Van der Graaff generator zaps the top of the cage with approx. 15 gazillion volts. 10/10 would recommend.

For more on this topic, check out Richard Hammond putting this theory to the electrifying test on Top Gear: https://youtu.be/ve6XGKZxYxA

Follow us on Instagram to keep up to date with Myth Busting Monday and learn more fun facts each week!