If you can project a microscope via a camera, make some dilute cornflour in water suspension (about what you would make gravy with), put it on a slide, and then hit it with a hot air gun while it is under the microscope, you can see the starch granules swelling up in real time.

There is a video I took a while ago here (it isn't timelapse, it is in real time):

https://www.thenakedscientists.com/get-naked/experiments/cornflour-and-gravy

Dave

http://sciansell.co.uk

On 10 June 2018 at 16:41, Ellie Cawthera <[log in to unmask]> wrote:

Hi Stu,

 

It's bit odd perhaps but the first thing that comes to mind is a tampon! Cut the string cut off and it should look like a large grain of rice.

 

Good luck with the demo :)

 

Ellie

 

On 10 June 2018 at 15:22, Dr Stuart Farrimond <[log in to unmask]> wrote:

 

Hello all,

Looking for ideas please. I want to do a demo to show what happens to rice when it cooks in a visual way, i.e. Starch granules swell. Some way to show how it swells - may be with some kind of large rice shaped sponge? (Although that's not very good example.)
Interestingly, both brown and white rice absorb equivalent amounts of water - the only reason to add more for brown is because the bran coat slows down penetration of water, so more water evaporates as you cook. In a pressure cooker, it's about the same (roughly 1:1 water to rice I think) regardless of type.

Looking forward to the ideas of the collective brain!

Stu

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