Guinness World Records recently challenged YouTuber Isabelle Ingham - aka SassyBelle - to attempt one of the records from our new Science & Stuff book.
The schoolgirl decided to go for the Longest distance to stretch home-made slime in 30 seconds.
You may have made your own slime before, but there are strict rules when it comes to attempting an official Guinness World Records title!
For example, for this attempt the slime has to be created using glue, water, borax, cornstarch/flour and food colouring - and weigh no more than 50 g.
We sent an official adjudicator to Isabelle's house to judge her slimey skills.
Watch the video below to find out what happened!
There are 10 fun DIY experiments in Science & Stuff, plus you can get the instructions on our website too.