Caution! Minds at work!

There has been a terrible robbery at the museum of rocks and soils. A magical liquid proven to make children 100% smarter has been stolen. Someone stole it by hiding it within a permeable rock.

But which rock could it have been?

 We received a package from the metropolitan police, containing evidence and a specimen of the magical liquid. We had to wear our goggles in case it was toxic! 

Choosing our equipment 

How many drops should we use on each rock? We had to control our variables. 

Has the water been absorbed? Is the rock permeable? 

 Delivering our reports to the office to be faxed to Scotland Yard.  

A fantastic investigation- who knew that we could learn so many scientific skills through working for the police!?