Measurements and comparisons are a fairly important part of the school curriculum for young children. Now a new app called Curious Ruler wants to help them learn.

It’s been developed by Curious Hat, which has made a succession of inventive children’s apps over the past couple of years: Curious Playground, InfiniScroll and Eye Paint Alphabet to name but three.

Curious Ruler is very intriguing: billed as “a way to measure objects around you and compare”, it gets children to choose a reference object from 36 possibles – from coins and Lego bricks to DVDs and iPads – then place them next to another object they’d like to measure.

Then, they drag on-screen sliders to measure the second object, which they can then compare to other objects – for example, finding out how much longer their teddy bear is than a CD and so on.

“Did you know that the iPad 3 is as long as 27 pennies? With the Curious Ruler you do!” as the App Store listing puts it. “The interaction is limitless, fun and educational.”

We’ve been playing with the app, and it’s good fun – but also a spark for conversations with your children about measurements and comparisons. We suspect it could come in useful in schools that are using iPads in class, too.

Curious Ruler is a free download for iPhone and iPad on Apple’s App Store – it has no in-app purchases either, although it’s likely to start being charged for upfront in the future.