It is not necessary to be an expert
in everything. Answering a question with, "I don't know", sets a
high model for your child. Following with, "How could we go about
finding out?",
raises it another level. It is not worth the effort to pursue
every question. But for some questions it is important to
follow through.
Sometimes it possible to give a child "quality" time
without much interruption of your own activities. At the same
time it can be "educational", developing language skills, reporting
skills, observation skills. All of which are important science
skills.
How can you expect someone to make intelligent descisions concerning global ecology ,
when they are ignorant
about their local environment ?