ใช้เป็นของเล่นเด็กๆอนุบาล
https://sarahssweeties.wordpress.com/category/homeschooling/page/10/
http://teachbesideme.com/magnet-boats-and-more-science-fun/
https://www.google.co.th/search?q=water+cap+toys&rlz=1C1GGGE_thTH522TH522&espv=210&es_sm=93&source=lnms&tbm=isch&sa=X&ei=O-EOU-HBJIu6iAec6IGoBA&ved=0CAcQ_AUoAQ&biw=1440&bih=805#q=water+cap+fun&tbm=isch