Get them wondering why things are made the same size and what would happen if they weren't.
There is a lot of practical activity that can be done with measurement. Introduce them to measuring instruments - rulers, scales, measuring jugs, and get them to research units of measurement and what tools can be used for measuring.
All training apps are subject to Apple's standard licensing agreement. Copyright is protected for Alexander Watt 2011/ 2012/ 2013/ 2014/ 2015/ 2016. Feedback is welcomed in terms of adding functionality to downloaded apps. Apple, iPod, iPhone, iTunes, iPod touch are registered trademarks of Apple Computer, Inc. If you find links you find inappropriate please email me at firstname.lastname@example.org and I will check it. I have provided these links with the best intentions however I cannot be held responsible for their content.