Magic or Science

[bluedragon]

Greeting all, I have a question a stupid one , am not good at science sorry guys.
Stormbag - Sandbag flood how does theses alternative sandbags *with no sand* work out?
That looks like magic to me ....lol
Thx for any answers

 

[Alien Allen]

did you view the video

it is not magic

there is a polymer inside the bag which when wet expands

bet they are not cheap