Ooh, this one is so fun! My kids absolutely loved doing the Mentos and soda experiment, the look on their faces bila the fountain shoot up was priceless, haha. Basically, the fizz (carbon dioxide) dalam soda is trapped and desperate to escape, and when the Mentos go in, it gives all those bubbles a surface to rush out from, so everything shoots up like a geyser. A few of us mums did this at a birthday party once and semua the kids were screaming with excitement (just do it outside or wear old clothes, trust me!). Definitely one of those simple science experiments that teach something real about how liquids and gases work, and the kids think it's pure magic.