Teller speaks about demo chains

2 02 2017

This video is worth watching because you get to see and hear Teller doing magic. 

In his talk Teller expertly demonstrates how magicians take advantage of how people begin to gain understanding as they see things being repeated. 

As he says in his introduction: In real life you see something repeated and you start to pick up a pattern. 

Teller doesn’t just tell us, of course, he demonstrates it. In a perfect example of Hook and Reveal we are shown the trick and then left desperate to know what is going on. He doesn’t leave us hanging for long, he moves straight into a Tell and Show explanation of what was he was actually doing with the coins perfectly illustrating the point he wants us to grasp. 

There’s a lot to enjoy about this short talk but the one takeaway I’d like to highlight is the power of the repetition. He doesn’t just reveal one coin and move onto another trick. He has built an entire piece around a simple idea. 

As the trick progresses Teller shows how at every reveal he manipulates what we think we’ve already learned so he can surprise us with the next twist. As science presenters we can use the same powerful technique to reinforce and explain rather than baffle our audiences. 

If he went straight to producing coins out of someone’s glasses the trick would be a very unsatisfactory trick. But because he builds a series of productions before we fully appreciate and enjoy what has just happened. 

When we present science if we link our demos, as we move through what I like to call a Demo Chain we can harness this same technique of repetition but instead of using it to fool your audience like a magician you use it to aid their comprehension. 

Follow the Demo Chain link or check out any of Steve Spangler’s work to see good examples. 

Pecha kucha demos

9 08 2016

I was privileged to attend the BIG Event this year in Belfast and I enjoyed their cheekily titled “Best Demo Competition”. 

For those of you that haven’t seen the Best Demo Competition it’s cheekily titled because they don’t limit participation to those presenters who might be considered the best – this year there were novices and early career presenters alongside some demo wrangling stalwarts. They don’t expect the entrants to show a demo – this year just under half the contestants actually performed what might be considered a STEM demo, the rest were more science cabaret or science variety acts. And despite the fact no other events are programmed against it and there’s a trophy given out to the winner at the gala dinner described as “one of the least valuable yet most highly prized honours in UK science communication” there are no voting criteria and those attending the event are told not to take the competition bit seriously (LINK). 

(It really shouldn’t work but I’d recommend anyone go and see one if they can. As long as you don’t take the title at all seriously it is great fun.)

Entrants to the “Best Demo Competition” are given 3 minutes (or so – the winner went minutes over time… another example of how loosely BIG applies the term competition!) and this year most tried to put their demos into some sort of context. I think demo presentations should always have a story but I know this lead to some comments that the best demo competition was more of a best routine competition.

I thought more of a problem was this year most entrants chose to perform single concept-single demo presentations which I thought was a shame. 

Concepts explained with just one demo inevitably end up as being either show then tell or tell then show. Unless the presenter is happy to get on and get off fast there is always large amounts of speaking either before or after we see the demo. 

The time limit is a very good idea because it forces contestants to get on with it. I enjoy watching YouTube videos of the ASTEC Live Demo Hour but I think most of the performances could benefit from a stricter time limit.

The problem with the 3 minutes allotted to the “Best Demo Competition” in almost every case it is still far too long for the presentation of just one or two demos. 

The majority of contestants this year tried to fill or pad their demos with stage business to take up their allotted time. Unfortunately this padding more often than not distracted attention and focus from the demos rather than aid our understanding. I think this was what those people who were unhappy were unhappy with – story isn’t the problem, neither is a routine, but a weak story and/or overly long routine is. 

All but one of those who managed to perform more than one demo in their allotted time performed individual demos that were loosely themed to go together (eg: involving the same fruit or that looked like drinks) rather than scripted tightly to make a single concept-multiple demo presentation or what I would call a demo chain

The contestant I personally thought should have won performed three chained demos, way under time and didn’t resort to costume, dance or song to unnecessarily jazz up what she was trying to demonstrate. 

In her presentation we were shown two demos to explain the science she was trying to communicate (thermoclines). The first demo most of the audience would have been familiar with (see picture below) but the second was new, at least, to me.  Then we were shown a third big finale that combined the previous two demos and reinforced the science underpinning the presentation that I thought was excellent. 

This brings me to Petcha Kutcha

The Petcha Kutcha (PK) format was developed in 2003 to specifically deal with the problem of speakers talking at too few slides for far too long. It was originally conceived for architects but as they say in the PK FAQ we can all fall in the same trap:

Give a microphone and some images to an architect — or most creative people for that matter — and they’ll go on forever! 

The PK format is simple. Each speaker talks whilst 20 slides play in the background for 20 seconds each. This means you avoid the problem of too few slides – everyone has 20; and you limit the time anyone can speak – 6 mins and 40 secs. 

The time limit is part of our “Best Demo Competition” format. Could our presentations benefit from insisting on a certain number of demos as well?

I have been asked to take part in a PK event and instead of talking whilst 20 slides play for 20 seconds each I thought about trying to perform 20 demos instead. 

The only way this would be possible would be to chain my demos so each linked to the demo that came before and after and helped tell one consistent story. There would be no time to explain and perform even one unconnected demo in 20 seconds. What I envisage is a series of linked demos, most using the same equipment, that can be woven together in the way series of card tricks are woven together in a magician’s routine. 

Half the time I think about this 20 seconds seems impossibly fast but then 20 seconds for many PK speakers ends up seeming a very long time when they are on stage. This very talented PK speaker shows this perfectly at 1:50.

If my PK experiment presentation works, next year at the BIG Event I might suggest as session where we explore this further. Perhaps a strict 20 seconds per demo will prove unworkable and unnecessarily rigid but it should be easy to ask people to perform at least three chained demos in two minutes – my favourite “Best Demo Competition” entrant took this long to perform her three demos. 

I’m looking for inspiration towards the work of Steve Spangler who always manages to chain his science demos and magicians like this. 

I count 11 reveals of the same “Ambitous Card” in just 2:40 mins!

I’d be fascinated to hear from you if you’ve tried something like this yourself or if you’ve any footage of someone that has. And as usual I encourage people to post any comments. 

Science nuggets

23 03 2016

My three evaluation questions are What’s the Story? Who’s the Audience? and Where’s the science?

Today I’d like to think a little about the third question. 

Every science demo we perform relies on or reveals an essential nugget (for want of a better term) of science. The way we explain that nugget of science depends on our Audience and the Story we have chosen to tell. Nevertheless each demo is still underpinned by a nugget of science and if we fail to get that across we might as well not bother with anything else. 

Take this classic demo.

You probably know what’s going to happen. The little ball is going to rocket up off bigger ball. It’s a spectacular self-working demo that requires cheap non-specialist equipment. No wonder it is such a popular choice for presenters. 

The demo is comprehensively described on the page where I took that picture from. What is the nugget of science in this demo?

Most times I see this performed the balls are dropped, the little ball shoots off, we are asked to marvel at what happened, often we are shown it happen again, then it is explained. 

But what’s the nugget?

It doesn’t matter who your Audience is or what your Story the nugget here is that 

the basketball doesn’t bounce as high with the tennis ball on top

If your presentation of this demo doesn’t get across this simple point that the basketball will bounce to one height by itself but a lower height with the tennis ball on top then you’ve missed the nugget. 

All the talk of conservation of energy and transfer of momentum will mean nothing if the different bounce heights haven’t been noticed. 

Once you’ve identified the nugget then then the best presentation of the demo should be clear. In this demo we need to show the balls dropped separately then together. 

This video does a very good job of explaining it. 

It should be clear from watching this video that explaining this demo takes time and you can cover many science topics with it. What they do well is show the nugget: the basketball doesn’t bounce as high with the tennis ball on top.  

This video gives another example to stress the point. Someone double bouncing someone on a trampoline will send the other person higher but they won’t go as high. 

We must search for the nugget in every demo we perform. Every demo has one single piece of scientific information in it that, however we choose to present it, must be got across. 

I’ve just had the pleasure of spending a week working with liquid nitrogen. The context for the show was space and I was able to use the LN2 to demonstrate alien atmospheres, the formation of clouds, changes of state, reversible and irreversible reactions, fractional distillation and water content in living cells but I was careful to not lose sight of LN2’s science nugget:

liquid nitrogen is the coldest substance you will ever encounter

If you are working with LN2 and your audience hasn’t grasped that liquid nitrogen is unbelievably cold then whatever else you’ve tried to get across won’t have been properly understood. 

I know reading this that probably sounds obvious to you. If you’ve managed to get your hands on a dewar of LN2 then your training will have stressed the extreme cold to you. Remember though the audience might not have seen LN2 before and even if they have it was probably at another science event where it’s properties might not have been properly explained. 

Just as with the ball on ball demo height difference you must cover the extreme cold of the LN2. How do you know if you’ve covered the nugget? Ask your audience. 

If I was being honest I’d say more than half, maybe even three quarters of the LN2 demos I’ve watched over the years haven’t stressed the extreme cold enough that the audience has grasped it. I always get someone in the audience of a LN2 show I’ve watched to tell me something about the LN2? Too often, even after prompting, they can’t tell me that it is incredibly cold. If someone in the audience of a show I’ve done can’t tell me I immediately review how I’ve explained it. 

Take the fizzy tablet dropped into a film canister demo. Here’s the wonderful Steve Spangler performing this demo. What’s the nugget?

Here the nugget is when the tablets get wet they fizz. He demonstrates this simply by putting a couple of tablets in a glass of water. 

It is too easy to assume that your audience will know what an Alca Seltzer tablet does and forget to stress this nugget. If you don’t show the tablets fizzing then everything that follows might be misunderstood. 

What you then do with the nugget is up to you. Acid plus base reactions, build up of pressure, solids and liquids taking up less space than gases, compressibility of gases, friction and seals can a be discussed but just as with the LN2 and the balls if you’ve not covered the nugget you’ve massively reduced your chances of your audience understanding anything of what you are doing. 

the basketball doesn’t bounce as high… the LN2 is extremely cold… the tablets will fizz when they get wet

Find your nuggets in all your demos. Take the time to cover them clearly. Only then go on to show or explain what you’d planned. 

There’s one more excellent example at the start of the Steve Spangler clip. He demonstrates the cornflour on a speaker. 

What’s the nugget with the speaker demo? The speaker is vibrating

Steve takes the time to show this using some ping pong balls. That bounce out of the speaker. 

It’s such an obvious and simple thing to show but in all the times you’ve seen this demo being performed ask yourself how many times have you seen a presenter take the time to show this absolutely vital piece of information? 

Liquid nitrogen flowers

7 03 2016

This is another look at a piece of internet science communication. In the first we looked at a section from Cosmos.

This is a small piece of The Science Museum’s Energy Show which has been officially posted onto YouTube by Focus magazine. Even though it depicts the performers without an audience it is fair to assume the directors and producers of the show were happy not only with this piece but with it being seen widely as an advertisement for their production.


Whilst it can be unfair to take a video out of context, often we miss important information either before or after the selection, this video seems to show an entire section of a rehearsed and scripted show so it is fair to assume this is how it is presented live. I think it is fair to critique what they have chosen to put on YouTube as an advertisement of their show. I have received replies from The SM before about comments I’ve made about their productions and I’d be happy to hear from them again about this and print any comments they’d like to make. I’m sure everyone reading this realises this piece is critique written with the hope that it informs everybody working in our industry. I write this with the best possible intentions and congratulate The SM on their ambition with the show.

If the link doesn’t work search ‘Science Museum Energy Show Dunking Flowers in Liquid Nitrogen’ and you should find it.

Even though this video shows only a small part of presumably a larger piece it demonstrates the dangers of introducing dramatics and characterisation into a science presentation. In this video the ‘business’, or the incidental activity performed by an actor for dramatic effect, doesn’t just fail to reinforce the science message it actually distracts and misrepresents it.

This is a shame because with a few adjustments they could have retained all the drama but used it to reinforce the essential science message.

There is a good reason dipping a bunch flowers into liquid nitrogen has become a science presentation standard. Flowers are a great way to show how fast something can be frozen in this incredibly cold liquid. That is the whole point of the demo. The flowers freeze extremely fast. This treatment of that demo has lost sight of this (if the writers were ever aware of it).

To comprehend what is going on the audience’s attention needs to be drawn to the state of the flowers BEFORE they are dipped. They are soft, they are flexible, the petals and leaves are firmly attached to the stems. Once the audience’s attention has been drawn to these characteristics then the AFTER, the disintegration of the flowers, vividly highlights that they have undergone a radical and fast change. The liquid nitrogen has frozen them.

Depending on the age and stage or your audience and the additional points you want to get across you can introduce other pieces of information. For example: flowers are made up of water that will freeze quickly at liquid nitrogen temperatures or flowers are made of cells that burst as the water inside them expands etc.

If we break their piece down:

8 secs: Why do they mention Halloween? If you wanted to draw attention to the fog it would be better to say: these are like the clouds your breath makes on a cold winter’s day. It performs the same job but accurately reflects what the audience can see AND what is actually happening, water droplets are being condensed out of relatively hotter air.

15 secs: Why enter into the fake dialogue? Is this from Star Wars? And what is it with that annoying noise the presenter makes? It took some digging around by this is the actual scene from The Empire Strikes Back this section seems to be referencing. (if the link doesn’t work search ‘Han Solo frozen in Carbonite’).

I’m sorry but for starters, and I hate to be the one to break it to you, Star Wars isn’t real…

Worse, Star Wars famously uses scientific terms incorrectly. Jedis use ‘the force’, Han Solo’s ship ‘made the Kessel run in less than 12 parsecs’ (a unit of distance not time), and ‘Carbonite’ is actually an early explosive not something cold. This is not me being grumpy, these inaccurate uses of real scientific terms are genuinely confusing for kids.

Using the example of Han Solo being frozen as being similar to freezing flowers in liquid nitrogen is like saying the way Superman flies is similar to the way planes fly. Yes there is a link, but making the comparison doesn’t reinforce any science message. Han Solo is brought back to life and apart from temporary sight loss is none the worse for his experience. The flowers get destroyed.

In the time it takes the performer to act out her dialogue and gurgle as she slowly drops the flowers into the liquid nitrogen she could easily have said: these soft and flexible flowers are mostly made up of water, I wonder what will happen to them and all that water when it goes into the incredibly cold liquid? She would also have had time to rub the flowers against her cheek to show they were soft and flexible, she could also have hit them off something or maybe dropped them to show that flowers that haven’t been frozen in liquid nitrogen are not going to disintegrate.

If you have to keep the Star Wars reference then work out a way that we know that the flowers are meant to be Han Solo. In the clip this is not clear at all. And if the point is that the actress thinks the flowers will be preserved intact and unharmed like Han Solo we need this pointed out as well. I think the Star Wars business here is not a help but a hindrance and I’d suggest it was got rid of.


26 secs: “Why are Anna’s flowers on fire?!” If the actress is trying to freeze the flowers like Han Solo was frozen why would she suddenly be afraid that the flowers were on fire? Why isn’t she aware that there is no fire here?

And from a science content point of view why would you want to make a link between the water vapour fog we see and smoke? Why would you want to introduce and reinforce one of the most common misconceptions audiences can have about liquid nitrogen? People are familiar with fire, heat and smoke. When they see clouds of fog coming out of a bucket of liquid nitrogen they often think they are seeing ‘smoke’ and assume if there’s smoke there must be fire. One of the most important things to get across when working with liquid nitrogen is that this fog isn’t smoke, there isn’t any fire, it isn’t hot. In fact, it is totally not hot, it is a substance colder than the surface of the planet Neptune!

What is actually happening is that the room temperature flowers are being dipped into a liquid that boils at -196 degrees Celsius. This is like dipping a piece of hot iron which has been heated up to +196 degrees Celsius into really cold water. The ‘hot’ flowers make the incredibly cold liquid boil. Although it might look like ‘smoke’ the clouds that we see are totally different. A good way to make this point is to get the audience to notice that the clouds are falling to the ground not rising up like we’d expect smoke to do.

35 secs: “It’s water vapour. The liquid nitrogen is so cold that it is causing the atmosphere around it to condense.”

This show is advertised as being aimed at English Key Stage 1 and 2, that basically covers primary school. In that one sentence the following concepts are mentioned:

water– are the children aware of water existing in three states? are they aware there is water in the air around us? do they understand that the clear colourless liquid in the bucket isn’t just hot water? Do they know that we call water when it is a gas…

water vapour- is the cloud actually water vapour? No, the clouds we can see are actually water droplets suspended in the air. It would be better described as fog which begins to form when water vapour condenses into tiny liquid water droplets in the air.

atmosphere– are the children aware of this term? Do they understand they are surrounded by air and that air is also inside the bucket?

condense– are the children aware of this term? Do they understand that things can exist in different states of matter? That water in one form can be turned into water in another form?

Finally, the sentence “[It] is so cold that it is causing the atmosphere around it to condense” is wrong. It is not the atmosphere that is condensing, it is the water in the atmosphere that is condensing.

If you have chosen to prioritise the drama and characterisation over science content and you plan to get the science out of the way with a single sentence then I’d hope that you could make a better job of it than this. The language used here is not suitable for the audience, the explanation given is incorrect, and most importantly the science spoken doesn’t actually reference what is most important part of this demonstration anyway- that the flowers have been frozen!

44 secs: “I thought they were toast”. Just when the script has tried to dispel us of the heat/fire/smoke misconception for the sake of a silly throw-away line the concept of heat/fire/smoke is reintroduced. This is is totally counter productive.

1 min: “I have cryogenically preserved your flowers in liquid nitrogen just like they did to Han Solo in The Empire Strikes Back“. What does croyogenically preserved mean? Is this something the children will be familiar with? And have you preserved them? We are about to see that you haven’t as they are going to get destroyed. Cryopreservation uses liquid nitrogen to flash freeze delicate biological tissues to avoid the freezing that destroys cells. As has been said already, the whole point of this demo is that the flowers are NOT preserved. The water in the cells is frozen and this is why they act so differently after they have been dipped in the cold liquid.

1 min 17: the flowers are destroyed by hitting them over someone’s head.

The video stops here. Perhaps the presenters go on to examine the pieces of flower that have fallen to the floor. Perhaps they go on to say- wow, that was unusual! why did that happen? and then do a series of other experiments to show why the flowers behaved so strangely after being dipped in the liquid nitrogen. Perhaps they found another bunch of flowers and repeated the demonstration drawing attention to the points I’ve made above. I haven’t seen the show so I don’t know.

What I would say is that even if all these points are addressed afterwards the writers have missed a trick here by setting up this piece in the way they have. And if they move onto something else entirely after the flowers are smashed on the actress’s head then it is a real shame because they have missed what I consider to be the most important part of a science presentation.

However theatrical you want to make a science-based presentation there has to be some genuine science content or you are mis-selling your product. All of the theatrics in your show should act to reinforce your key science messages certainly not distract or confuse the audience or worse mislead them. 


Where’s the (rocket) science?

27 02 2016

Last week I bemoaned the lack of scientific content in ITV’s new “science-based entertainment” show. Episode 2 wasn’t any better I’m afraid. 

I’m not going to go on and on. We’ll just look at one piece to show the perils of ignoring the science in a science demo. This is a lesson we can all learn from. 

The big set piece this week was a giant-sized version of the bowling ball conservation of momentum demo.   

The idea is simple. In the traditional presentation of this demo an experimenter stands with his back to a wall. He cannot move any further back even if he wanted to. A bowling ball, suspended from the ceiling on a wire, is held against the tip of his nose and allowed to swing away from him. 

The ball swings away then starts to swing back… It’s going very fast… It’s getting closer and closer… Oh, no, he’s going to get squashed… He is trying to squirm back but the wall is in the way… Oh, the humanity!

Then the ball stops (literally) millimetres away from his nose. We all laugh in relief and explore the science. 

I set up and performed this demo for the BBC show Bang Goes the Theory Live when we were in Blackpool performing in the shadow of the Pepsi Max Big One roller coaster at the Pleasure Beach.

I didn’t put up a backboard or do it against a wall each of the TV presenters had to come up on stage hold the ball to their noses and not flinch as the ball came back towards them. I set it up that way because they all understood the science. It was a test of their confidence and courage. 

The science is simple. Drop a ball onto the floor and however bouncy the ball and hard the floor the ball cannot bounce to the same height it was dropped from and it certainly can’t go any higher

This goes the same for a ball that is rolled down the inside wall of a bowl. It cannot reach a higher point on the opposite wall and it certainly won’t reach a higher level than it was let go from when it returns

I used it in Blackpool to show why a roller coaster is towed up to its highest point at the start and then released. Despite all the ups and downs, accelerations and decelerations, and in this case a loop, the car never returns to the same height or goes higher.  

And it’s the same for our bowling ball. As long as the ball isn’t pulled back further than the tip of the experimenter’s nose, it can’t reach a higher point on its return so it can’t smash into the experimenter’s face. Knowing that, however, doesn’t make it any less scary or nerve-wracking for the person in the way or dramatic for us to watch. 

How you explain the science depends on your audience and your aim in doing the demo. One way might be to say energy cannot be created or destroyed. Our balls start with a certain amount of energy. As a bouncy ball bounces or a bowling ball swings friction and air resistance mean some energy is transformed from gravitational potential and kinetic to heat and sound so the balls can’t reach the same height or speed again. You might just say this is why you need to be pushed on a swing

How you explain it doesn’t matter but how you demonstrate it is very important. 

If you don’t show the before, where the object is released from, the after, where it ends up, is meaningless. 

Say you released the bowling ball on the opposite side to the experimenter, so instead of swinging away and then back it just swings towards the experimenter, this is not the same demonstration. This isn’t science this is just trusting someone not to have pulled it back too far or hoping they don’t give it a shove. 

It’s no longer about the experimenter putting their life in the hands of science it’s really just an exercise in measuring how far something is going to swing and putting your target just out of reach. You don’t need to reference the laws of Conservation of Energy you just need a long tape measure.  

And surely no one would do this as you lose all the drama and jeopardy of the before (as the ball is shown right up against the experimenter’s nose, you can actually see it touch his nose, the experimenter can feel it’s cold surface and smell it it’s so close) which makes the after (seeing it stop millimetres from his face) so tense and thrilling. “I don’t need a tape measure,” the experimenter can boldly say before they release the ball, “I trust science!”

And yet that’s exactly what they did on this weeks episode…

In both the small scale “science explanation” with Kevin Fong where they used a bowling ball and in the giant-sized human carrying version they pulled the balls back and just swung them across at the “unlucky” presenter who was apparently “in mortal danger” and “who really, really could die“. Yeah right. 

Instead of spending all that time building false jeopardy it could have been so much more dramatic if they’d respected the whole point of the demo- the science. 

Imagine the presenter in the human-sized ball being winched towards his colleague instead of away. Imagine the drama as they are shown close enough to touch,  close enough to share a last few drama-packed, whispered words “I can’t believe we are doing this! No one has even measured this! This could be fatal” etc before the ball is released. 

The ball swings away then starts to swing back… It’s going very fast… It’s getting closer and closer… Oh, no, he’s going to get squashed… He is trying to squirm back but the wall is in the way… Oh, the humanity!

But no. We saw this. The ball swung across once and stopped well short.   All the dramatic music and pieces to camera couldn’t mask the overwhelming sense of “so what?”.

Last week the science was ditched in favour of drama and hype. This week they went a step further, they ended up ditching the drama and hype because they ignored the science. 

The lesson we can all take away from this is simple: in a well thought out science-based demo the science isn’t something to gloss over, or worse ignore totally, the science is key. The science doesn’t make a demo boring the science makes the demo

Or, in your hunt for drama and entertainment in your science-based show, don’t throw the baby out with the bath water as my old Nan would have said. 

0.85 degrees what?!

3 03 2015

The BBC have produced an interesting program looking at the mathematics of climate change. [Climate Change by Numbers – it’s on iPlayer throughout March 2015].

The show was stylishly presented with some interesting LED persistence of vision graphics.

Personally I would have preferred accurate graphics overlaid in postproduction rather than wobbly graphics produced live. The presenter walked across the frame holding what looked like a broomstick fitted with LED lights which then painted the graph across the screen.

When your whole thesis surrounds the accuracy of data it seems strange to then represent this data in such an wobbly way.


I suppose programmes need hooks to grab the audiences’ attention and this was considered “a fun way to present boring data.” I would not have done it this way but I can forgive them their choice.

What is much harder to forgive was their representation of the figure that justified the whole half hour segment.


Where are the units? 0.85° what? It’s a temperature measurement so there are three units to choose from. The unit was mentioned briefly by the presenter but I find it very strange that it was not added to the end of that graphic. It’s not like there wasn’t space in the shot.

(And it’s not as if they couldn’t have added the missing unit in postproduction afterwards. Straight lines were regularly added to the wobbly graphs in postproduction during the rest of the segment- something that to me reveals just how much a gimmick the drawing of the graphs were…)


I have no idea what the presenters of this program thought about this. Perhaps they argued for the inclusion of units and were overruled. Whatever the reason it is a real shame when a programme about mathematics, presented by mathematicians, misses out something so essential.

If you don’t want to watch the whole show watch from the 25:45 min mark to see just what I mean. I’d be interested in your thoughts in the comments.

Inhaling Helium

29 11 2014

To get the most out of this I need you to do something. I want you to hold your breath as you read this post. I promise it will make sense later.

Ready? 3-2-1- take a big breath in… and lets get started.

Despite any scare stories or news reports you might have read helium cannot hurt you.

Think about it. If inhaling helium from a ballon was dangerous would McDonalds hand out balloons filled with helium with their Happy Meals?

How’s the breath holding going? Starting to feel anything yet?

Helium is a wonderful gas with many amazing properties and uses. It is not dangerous in and of itself.

Helium gas is odourless, tasteless and non-toxic- it’s not poisonous if you breathe it. Helium is lighter than air which is why balloons float and your squeeky helium voice goes back to normal- it floats up and out of your lungs all by itself.

Let me repeat helium is not poisonous and sucking small amounts from a balloon cannot hurt you.

I bet you are finding it harder and harder to hold your breathe. Can you feel that burn? Can you feel that urge to breathe? Good. You can stop now. Breathe again. Thanks for playing along.

The dangers of sucking in helium are massively over exaggerated in the reporting of the vanishingly small number of helium related incidents.

People get into trouble inhaling helium in three ways.

1. Most commonly people faint because they don’t realise their brains are not getting enough oxygen.

2. Occasionally people suffer fatal lung damage because they suck it straight from pressurised cylinders.

3. And an increasing number of people use it as a very effective way to commit suicide.

Lets deal with 2 and 3 first.

2. Pressurised gas cylinders are dangerous whatever gas is contained in them. If you suck gas directly out of a cylinder the force of the gas released is easily strong enough to rupture the alveoli (or air sacs) in your lungs causing them to bleed. Death follows immediately as you literally drown in your own blood [REF].

Deaths from sucking helium out of cylinders are not due to the gas being helium. We should be reporting these deaths as pressurised cylinder deaths not helium deaths. By not stressing the vital role of the pressurised gas we are not just unfairly demonising an inert substance but failing to make people aware of a real risk.

3. If you search for ‘inhaling helium death’ you don’t need to scroll far to find instructions on how to use helium as a method to commit suicide. In the 10 years between 1993 and 2002 only 3 deaths were recorded in England and Wales with helium mentioned on the death certificate. In 2013 alone the number was 62 [REF See table 6a]. If we assume the amount of helium balloons in England and Wales has stayed constant since 1993 (and I can’t find evidence to the contrary) then we can’t say inhaling helium has suddenly got much more dangerous. The way a small number of people very deliberately inhale helium has changed and this is nothing to do with casual balloon sucking. These tragic intentional suicides should not be used or confused into the McDonalds balloon data set. They are very different.

1. What happens often is people faint dramatically when inhaling helium because they forget they can’t breathe helium.

Take a big breath again.

The air we breathe in is a mixture of
78% nitrogen
21% oxygen and
1% argon.

Breathe out.

The air we breathe out is
78% nitrogen and
1% argon (nothing happens inside our lungs to those inert gases) but now about
16% oxygen and
5% carbon dioxide.

It is a myth we ‘breathe in oxygen and breathe out carbon dioxide’. We breathe in just over one fifth oxygen and breathe out just less than one fifth oxygen with the difference being made up of carbon dioxide [REF].

When you held your breath earlier it wasn’t you running out of oxygen that made you want to breathe it was actually the build up of carbon dioxide.

Think about what’s happening when you’re sucking on a helium balloon. Instead of 21% oxygen you are getting 100% helium. Effectively you are holding your breath but because you are sucking in a gas and there’s no build up of carbon dioxide you’ve got no way of knowing. When you suck in helium you feel totally normal- there’s gas in your lungs, there’s no air hunger because there’s no carbon dioxide build up- but your body and brain are silently being starved of oxygen.

If you just take one breath of helium it’s like holding your breath for 20 seconds or so. Your body can cope easily. This is harmless good fun.

But if you were to do it twice or three times without stopping to top up on air then it is like holding your breath for a minute. Your body can’t cope with this and that’s why you faint.

Your brain is an amazing machine. When you are doing something stupid it can over-ride your conscious thoughts. In this situation it basically says you are being stupid and I want you to stop.

When you are lying on the floor you are no longer breathing helium but air. Everything starts to go back to normal and you come round albeit to the panicked looks of concerned parents and friends.

Once again its not the helium that’s caused the damage (or rather drama unless you’ve hit yourself off something as you fainted) its the lack of oxygen. But poor old helium gets the blame.

Remember helium can’t hurt you. Helium is inert. But that doesn’t mean if you don’t think about what you are doing you can’t have an accident around helium.

Digging around the accidental causes of helium related deaths I could find no examples of people dying from using McDonalds sized balloons to suck in gulps of helium. For instance two teenagers died but they were found inside a giant balloon filled with helium. The well reported Ashley Long death involved a cylinder and face mask. And the tragic death of a Northern Irish girl was because she got her head stuck inside a large foil balloon.

Any death, accidental or intended, is tragic. But we must resist repeating nonsense about helium being dangerous and even deadly. Communicating the real risks- of pressurised gas inhalation and accidental asphyxiation- will actually make people much safer.

Today (2/4/15) I found this amusing video on YouTube. Helen Mirren and Jimmy Fallon ask each other questions whilst inhaling helium.

If sucking helium gas from a balloon was dangerous there is no way the famously risk averse American TV networks would show it.

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26 08 2014

Are all the demos you perform as up-to-date and relevant as they should be?

Penn and Teller are two of my favourite performers. I think we could all learn a lot from watching their shows.

In 2010 they introduced a new trick to their show. It was performed on ITV as part of Fool Us.

If the link doesn’t work search Penn and Teller helium bag escape.

In the trick Teller escapes from a giant trash bag filled full of helium.

Teller is first sealed in a bag.

The bag is then filled with helium. We can’t breathe helium, a normal person should have suffocated by now.

In (literal) flash, Teller has escaped from the bag. The volunteer on stage is left holding the floating bag that seconds before trapped Teller.

Versions of the trick have been performed for over 100 years. Houdini himself performed a version and magicians today still perform versions of Houdini’s trick.

What makes Penn and Teller’s version of this trick so special is that they’ve updated it to make it relevant for today’s audiences.

If we want people to connect with our science demonstrations we need to follow the example of Penn and Teller and find ways to connect the demos to our audience’s everyday experiences.

The traditional version the trick is performed with a female assistant and called Metamorphosis. Houdini used to perform it with his wife Bess.

The magician not only escapes from the bag inside the trunk he switches place with his assistant.

When modern magicians perform versions of this trick I think most audiences are left unsatisfied.

The magician in a sack enters the box.


He is sealed in tight.

The assistant stands on top of the sealed box and then drops a curtain.


As the curtain falls we see the magician has switched places. He is now standing on top of the box from which he has escaped.


The assistant is then released from the locked box and tied sack.

Now I am not going to give away how this trick is done but if you’re sceptical like me you might be doubting the integrity of that box. The magician is asking us to believe that both he and his assistant have penetrated a solid structure.

I find myself asking the question: what is more likely, a faked box or human flesh passing through solid wood?

Compare it to Penn and Teller’s trick.

To me this is a lot more believable. I understand plastic bags and helium. I am familiar with how they work. If there was any rip in the bag surely the helium would escape? Teller must have somehow magically passed through the plastic.

It’s the same trick and yet Penn and Teller’s version is so much more effective. So why did the other magicians use that wooden box?

The reason is because the other magicians haven’t thought about why the box was originally used. They haven’t thought what is the best way to perform this illusion they have just gone along with the traditional way it’s always been performed.

As science presenters we need to be careful that we don’t make the same mistake.

At the turn of the last century every audience member would have been as familiar with a wooden trunk as modern day audiences are with the giant trashbag.

Houdini and Bess didn’t just perform with their wooden box they carried their world’s possessions around in it as they moved from gig to gig*. Everyone else would’ve done the same. Everyone owned a trunk which could be locked that protected their prized possessions. When this trick was originally conceived the magicians used a wooden box because the wooden box would never have been questioned.

Penn and Teller would never use a wooden box for audiences today. Who owns a wooden box apart from a tricksy magician? What they do brilliantly is think about how they can make the same illusion as effective as possible in the 21st Century. Instead of a trunk they use something we are just as familiar with- a trash bag.

When we are presenting classic science demos we should also be doing the same thing. We should all be looking for the anachronistic stuff that distances our audiences from our key message.

He is just one example I found in my repertoire. The popping film canister.


Why are we using film canisters? Yes, they pop nicely but how many kids in an audience have any idea what the film canister actually is?

Before the advent of digital photography everyone would have known what a film canister was. Every child would have seen their parents swapping the film in and out of those little plastic pots if they hadn’t done it themselves.

You could have been certain that everybody would have known the most important thing about them: that their lids fitted tightly on top and were difficult to remove.

Today we might still get a reaction from the canister lid popping off but if we think about it like Penn and Teller for a moment: is that reaction as effective as it used to be when everyone was familiar with film canisters and how they worked?

Just as a magician could still use a wooden box for Metamorphosis but he’s going to need to take the time to demonstrate to us convincingly that it is a solid and and gimmick-free wooden box, if we are going to perform the popping film canister we need to take the time to explain exactly the important properties of the canister.

Of course there is an alternative.

Instead of performing the popping film canister demonstration because that’s what we’ve traditionally always done we could ask is there a more relevant way that we can show the expansion of carbon dioxide gas in a sealed container using equipment that every child in today’s audiences would be immediately familiar with?

If Penn and Teller were performing science demonstrations you know that’s what they would do…

* “It was one of those early spring rains that chilled to the bone. The darkness was so thick that Harry and Bess began to think they were hopelessly lost. Still they plodded on through the mud, each carrying one end of the trunk that doubled as both a stage prop and their luggage.” The Secret Life of Houdini by William Kalush and Larry Sloman.


I have been in email conversation with the brilliant Paul McCrory who has made two very interesting points.

Firstly, he finds audiences are familiar with the film canister not because they’ve ever used one for its original purpose but because the canisters have become so common in science presentations and on YouTube people are now used to seeing them. I think that is fascinating. On the one hand we might be able to justify using film canisters because so many other people are, but on the other does that make us just like the magicians justifying their wooden trunk by saying everyone knows this is how the trick is performed, they are expecting to see a wooden trunk so I have to use one? I’d be interested in your comments.

Secondly, he saw P and T’s trick more like Houdini’s Paper Bag Escape than Metamorphosis. I’ve twitted Penn Jillette to see if he will comment. I didn’t know of the BP Escape, having looked it up I know where Paul is coming from- the paper bag and the trash bag are similar, as well as that HH spent time getting his volunteers to verify the bag he escaped from had not been switched or damaged and P and T let the helium filled bag float up to the ceiling to show there are no holes in the bag- but I think the instantaneous nature of the escape makes the Helium Trash Bag escape more like Metamorphosis all the same. The falling of the curtain serves the same purpose as the camera flash. I’m looking forward to seeing if Penn replies (I’m sure he’s too busy to even think about it but if you don’t ask you don’t get).


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Weather versus climate

6 06 2014

This is the first in a new series of posts that look at the effectiveness of science demonstrations.

TV science programs often use real life experiments or handy visualisations to help illustrate the point they are making. These are a valuable source of examples we can learn from as live science presenters.

Here is a great example from the rebooted series Cosmos. In this clip the presenter is explaining the difference between weather and climate. (If the link doesn’t work go to YouTube and search ‘climate change versus weather Cosmos’).


As you can see from the pictures the presenter is walking along a beach holding onto an excited dog who is running from side to side held back by its lead.

The first time I watched this I thought the dog running from side to side was really distracting, it stopped me from listening to what the presenter was saying. But then we get a shot from above that reveals why the dog is there.


As the presenter explains:

My friends meanderings represent the short term fluctuations, that’s weather. It’s almost impossible to predict what will attract his attention next.

But it’s not hard to know what the range of his meanderings will be because I’m holding him on a leash.

We can’t observe climate directly but what we see is the weather. The average weather over a course of years reveals a pattern. I represent that long-term trend which is climate.

Keep your eye on the man, not the dog.

When I’m assessing the effectiveness of any science presentation I ask three questions: What’s the story? Who’s the audience? And where’s the science?

I think this is an excellent piece of science presentation because it addresses all three of our categories excellently.

At the start of the clip the story is revealed. If scientists are so bad at predicting what the weather is going to be in 10 days time how can we be confident about their predictions for long-term climate change?

This is a really compelling question. If you’re a climate change sceptic this question could well form one of the main pillars of your scepticism. I think most people would be very interested to find out why we can be so certain about climate when we are so bad about predicting the weather.

And by using the dog this compelling story is linked to an everyday experience that most of us have had and everyone can imagine. There is no way to tell which direction an overexcited dog might go in next.

I think this explanation is excellently suited to its audience. Cosmos isn’t a show aimed at science specialists, it’s a show aimed at the general public who are no more than just curious. In fact one of the amazing things about the rebooted Cosmos is that it’s being shown initially primetime on Fox television which is not known for its sober science content.

Seeing a respected scientist walking along the beach with the dog is familiar and relaxing, it isn’t a scientist standing at the blackboard ready to bamboozle us with complicated equations.

Using a more conventional, mathematical-style graph would run the risk of turning off a percentage of the show’s audience. The level of words used in the explanation together with the example of the dog on a lead means this is perfectly suited to a general, non-science expert, audience.

Finally the science that is explained in this clip is spot-on. The argument is made in three steps.

1 Weather fluctuates (the dog)
2 This can seem chaotic but the fluctuations fall within a range (the leash)
3 The average of these fluctuations over time is the direction the climate is moving in (the man)

This is a very clear explanation fundamental piece of science that can be very easily misrepresented or misunderstood.

In summary I’d say this is an excellent piece of science presenting.

If I was to critique it I would say the dog running backwards and forwards at the start of the clip is distracting when the presenter is setting up his explanation.

Perhaps it would be better lose the dog for the first 30 seconds of the clip and just see the presenter walking along the beach. This would still be accessible and intriguing but the dog wouldn’t distract us from what the presenter was saying. Then the dog could be called across, the presenter could grab the lead and begin to walk off in the distance to make the point about the difference between short-term fluctuations and long-term change.

But maybe the dog is there to keep the attention of people who have just stumbled across the show, who are happy to just look at the dog, before the essential point is made as the presenter walks into the distance.

Personally I can’t wait for the new series of Cosmos to come out on DVD. I’ll be buying it and binge watching it the first day it does.