Your mobile is now ready to hang up, so tie a loop of thread around the centre of the straws.

Now comes the balancing act! Before you hang your mobile up, make sure that it is balanced. To do this, slide each piece of cotton along the straws until the straws are hanging horizontally (that's level). If each picture is a different shape or size, each one will weigh different amounts. Experiment to make sure that the whole thing balances.