By Rajesh Mirchandani
BBC News, Virginia
A group of American science teachers have travelled in a specially modified plane through restricted airspace in Virginia to conduct a series of simple experiments, designed with their pupils, in very low gravity.
Effortlessly, unavoidably, euphorically, you rise, the smile on your face broadening the higher you go.
As you bump the low ceiling of the 727, you hang in the air, or, with the slightest of forward motions, you slowly curl, head over feet, until you've completed a full turn.
Reach out to one side and you glide, seal-like, through a clear, waterless sea. It is, as promised in the pre-flight briefing, a zen moment. An instant of pure serenity.
And then a middle-aged science teacher smashes into you, as she revels in a brief second childhood while hurtling across the cabin in pursuit of an airborne M&M.
She's not alone, though. On this low gravity flight are about 20 science teachers from across the eastern US, enjoying a once-in-a-lifetime opportunity.
A specially-modified plane flies in a series of steep curves - a bit like a rollercoaster.
On the downward run you have the amazing sensation of weightlessness, a bit like you might in space. In fact, NASA uses flights like these to train its astronauts.
Each period of weightlessness lasts only around 15 seconds; then gravity kicks in.
And then you do it all over again, around a dozen times in all.
Rajesh Mirchandani experiences weightlessness
And although it is almost impossible to control your movements - and your laughter - the teachers are not just along for the ride: there is some science going on.
The teachers have brought simple experiments they devised with their pupils. One, Kim Snyder from Virginia Beach, has a balloon and a tape measure to test lung capacity in low gravity (she finds it harder to inflate the balloon than in normal conditions).
Another, Holly Mentillo, has two small bottles of differently-coloured water and a connecting tube: her pupils predicted water molecules would remain separate in low gravity. In fact, the two colours merged to form purple liquid.
But in some ways, the results are not as important as the method: the teachers are filming their exploits and will use the video as teaching aids in class.
Scientists in the making
"Instead of reading a book," Kim Snyder tells me, "it's like being in a book." She thinks her pupils will find it as "awesome" as she did. And that's the point.
Big engineering firms are worried America is facing a shortage of scientists.
Cheryl Horn, from Northrop Grumman, which sponsors hundreds of teachers on weightless flights every year, says it is one way to address the problem.
"We are hoping to increase the pipeline of engineers and scientists," she says. "It's good for the country because the country needs more engineers and scientists.
"We want to remain competitive globally and we hope that this is one way of supporting that initiative."
The hope is schoolchildren will see their own teachers and their own experiments in simulated weightlessness, and be encouraged to study science further, maybe even become scientists.
Nasa hopes programmes like this can help recruit tomorrow's astronauts too.
"Someone in this class could be on the first manned mission to Mars," Geoff Mitchell tells me.
He is a chemistry teacher at Washington International School, and is showing the video of his low gravity trip to his class of 8th graders (13-year-olds). So could it really inspire them to think about science as a career?
"I've always really liked science," teenager Anne Melkoff says, "so it almost makes me want to work a little bit harder, so I could do something like this."
Her classmate Sebastian Labarca agrees: "Usually science is a lot of equations, but weightlessness and zero gravity, that's cool."
Of course, it is a giant leap from school pupil to professional engineer, but this is about sparking young imaginations and possibly even finding the space explorers of tomorrow.
You can see Rajesh Mirchandani's full report on BBC One's Ten O'Clock News on Thursday, 22 November.