It's all about exploring – show your child the bin, let him or her explore and dig around for the hearts! You can talk about shapes and colours as they play – but it's really all about letting your child take the lead and learn through play.
In any sensory bin, little containers like small cups make for great 'dump and fill' action. Give older children tweezers so they can collect items and practice fine motor skills. Ask your child to collect 'all the red things', or count 'how many white things'. Terrific opportunity to mix and match items, bigger kids can pattern, little ones will group similar objects.
You'll be amazed at what your child comes up with on their own just by exploring!