As he steps back to a let a little girl go ahead of him at one of the most popular activities, five-year-old Christopher shares his thoughts on what he's been seeing and doing at Glasgow Science Centre's new BodyWorks exhibition.
"I'm really enjoying myself," he says. "I like learning new things. There's a lot here I haven't seen. I fancy being a doctor who helps people. Doctors are pretty scientific. It's how they figure out what's wrong with you. That's hard because it's inside you. But a lot of the things here help you look inside a person. I saw my own veins."
The little girl has gone and it's Christopher's turn to take his mark and find out, with the help of light beams and video cameras, just how fast he can sprint.
"The point of a soft launch like this is to learn what works and what needs tweaking," says senior science adviser Gillian Lang. "The starting block measures reaction time, for instance, but we've found it's hard for children to use. So we'll be setting it up tomorrow with just a starting line."
It's one of a few of the 115 interactive exhibits, research capsules and live laboratory experiences, that will need some tweaking before the official opening, says science director Robin Hoyle. "BodyWorks has been four years in the planning and development. Not everything is quite finished, so 20 families who are GSC season ticket holders - about 100 people - are giving it a test run for us tonight. Then we have a week to respond to what they tell us.
"What do I think of the exhibition? I think it's brilliant. It's a real step up in quality and content, and it's beautiful looking. The interactivity is fantastic. We've been working closely with research scientists to highlight their latest research, which is often amazing."
Funded by pound;2 million from the Wellcome Trust and pharmaceutical firm GlaxoSmithKline, BodyWorks is designed to explore the science that underpins health and well-being in the 21st century. Broad themes range from heart and blood vessels to the body's defences, the brain and the bionic body. Each one has a dedicated capsule that conveys the science, surrounded by games and interactives to engage visitors of every age.
"I've prepared a lot of the content of the research capsules, in collaboration with researchers," says science interpretation officer Sarah Gibb. "What we're trying to do in them is feed curiosity and wow people with how far we've come. We are telling stories and getting the science across.
"Here's a good example," she says, leading the way inside the brain capsule, where Martin Rutherford, Christopher's dad, is trying to spot differences in a succession of paired images that could indicate pathologies.
"It gives you a feel for what brain surgeons see," he says. "It's cool."
"They get images like this all the time," says Dr Gibb. "Then they have to decide if a particular mark is pathological or normal. Our brains age, just as our bodies do. These little white marks you can see - they're normal. So you need to be quite expert to tell what is pathological."
"It's really difficult if you're not a brain surgeon," Mr Rutherford says. "I'm a computer scientist."
The two other exhibits inside the brain capsule are 3D images using different technologies, such as CT and MRI, and a mummified brain in a jar. "Put these glasses on to get the 3D effect," Dr Gibb says. "Look at this image, which has a couple of aneurisms - blood vessels that are about to burst and cause a stroke.
"If they spot them in time, they can do cool surgery by inserting a wire mesh tube through your blood vessels all the way to your brain. They can also pack out the bulging bit with iron filings to ease the pressure."
"You'd have to keep your head away from magnets then," Mr Rutherford says. "An MRI scan would finish you."
"CT, which uses X-rays would be fine, though," Dr Gibb says.
"So is all this technology in use now?" Mr Rutherford wonders.
"It's used routinely to diagnose brain problems," Dr Gibb says. "All these images have been donated by hospitals around Scotland."
As Mr Rutherford heads back to his family, he describes the appeal of the Science Centre. "You learn something new every time you visit. Christopher would come every day if he could. So my mum and dad bring him, too. I know he's going to have lots of questions tonight about this new exhibition."
Raising questions and making people think is an important aspect of BodyWorks, says Gillian Lang, who led the project. "We started with a couple of concept statements, such as `Health and well-being in the 21st century' and `You are the scientist and the experiment'.
"We were keen for people to realise that we're all scientists when it comes to ourselves and our bodies. We all make decisions in our lives that affect the outcome of that experiment."
Smoking cigarettes is one of the worst decisions and several exhibits in the cardiovascular zone illustrate its effects, such as the two inflatable lungs in jars, one pink and healthy, the other black and diseased. "When we take lungs like this out on the road, with NHS smoking cessation teams, they see a dramatic increase in the number who sign up," Dr Hoyle says. "We don't try to persuade. We just present the science. But that is the effect."
Telling people something is unhealthy rarely works, agrees nurse teacher Ingrid Rutherford. "They think it won't happen to them. But if you show them something that means folk won't fancy them or they will lose parts of their body, they are much more likely to respond."
A number of other activities in the cardiovascular area were simple and effective, she says. "Like the one you squeeze with your hand to pump a liquid and feel the force the heart exerts with every beat. It's amazing how hard it has to work."
Derek Gallacher's two sons have tried just about everything tonight, he says. "They've really enjoyed it. They like all this interactive stuff. I have no background in science, though my wife's a teacher. But we've been bringing the boys here since it opened. Exhibits change and they (the boys) get interested in different things as they get older. Conor has just started secondary school and he's really into the physics now."
"The one I liked best was the pumping lung," says Jack Gallacher, 11. "It really showed me what happens inside us when we breathe."
While almost every BodyWorks exhibit has an interactive element, and a large number are educational games, the new exhibition features an added layer of engagement, Dr Hoyle says. "Over a dozen exhibits, such as the sprint, have barcode scanners that let visitors save their results and any photos or videos of them taken by the exhibit.
"They can then look at them later on our website and even share them with friends on Facebook or Twitter."
The exhibition is a real partnership, Dr Lang says. "We've worked with about 200 individuals on the science and we've also got ordinary people involved. We asked for volunteer expectant mums, then gave them little video cameras and asked them to record how they were feeling right through their pregnancy.
"We edited that all down and put it together with the science that explains why they were getting the heartburn and everything. So next week we have the mums coming in with their babies, who have all been born now. It's lovely."
While the majority of visitors to the science centre are non-scientists, a number do have a science background. "As a research biologist, there's not a lot in it I didn't know," says Jim Brewer, here tonight with his wife and two sons. "But it is a lovely exhibition. The boys are getting a lot out of it."
"One thing I discovered is that whether your earwax is sticky or flaky is genetic," Jenny Brewer says.
"Yeah, that was new to me too," Professor Brewer says. "I also found it was very easy to beat kids at the game where you have to relax your mind to move a ball."
"I wasn't so good at that," Mrs Brewer says. "Maybe that means men are better at relaxing than women - or maybe they just have less in their heads."
`I'VE BEEN LIVING AND BREATHING THIS FOR THE PAST YEAR'
"I am really pleased how well the evening went," says Glasgow Science Centre's science director, Robin Hoyle, after all the guests have gone.
I've been living and breathing this exhibition for at least the past year. The feedback from the visitors was great.
They were getting totally engrossed in the exhibits. I talked to one guy who was absorbed in the tools for micro-surgery and kept at it for ages. Then a wee girl came along and stood up on the table and managed it quickly - obviously a future surgeon. Adults in particular, we noticed, were getting drawn into the research capsules."
Creating the research content meant talking to lots of scientists, which was a real eye-opener, he says. "The exhibition is very much a partnership between Glasgow Science Centre and individual scientists and organisations. Every time we had discussions with scientists I would come away thinking, `That is amazing - I had no idea we did that here in Scotland'."