Einstein TEST TUBE Sand Slime. Einstein's test tubes are exciting mini experiments that achieve a big wow effect with little effort! The sand slime is a fun and relaxing activity for curious hands. Squeeze it, stretch it, form figures or small structures, and then happily destroy them again – this makes experimenting really fun and you'll become a little Einstein in no time! The experiment instructions are included with the product – or you can simply download them here and get started right away. Ages: 8+ years. Warning! Not suitable for children under 3 years. Choking hazard due to small parts.