How can a Montessori guide encourage a child's natural curiosity and desire to learn about the world around them?

The best way to encourage a child to be curious about the natural world is to exhibit curiosity and excitement. This means we must examine our reactions to various aspects of the natural world. Do we dislike, or are we phobic about spiders—or any other creature?  

We also need to have in the prepared environments examples of living creatures and plants; by learning to take care of these living beings we set the stage for ongoing appreciation of the natural world.

In a 0–3 environment one might have a bird, goldfish, hermit crab, snail, etc. —some creature that does not need much extra care.  Moreover, all environments need a variety of non-toxic plants.

In 3–6 environments there should be a representative of the 5 classes of vertebrates and a few invertebrates. This is to allow the children to care for these creatures, plus to be able to see the external characteristics of these zoological examples.  (This provides a foundation for the language materials referred to as Parts of Mammals, etc.) It sets the stage for learning the internal characteristics at the elementary level.

The same depth of experience should be evident in caring for plants.  Dissecting a flower and learning the names of the parts is more enriching than simply learning these things from pictures, e.g., Parts of a Flower.

Even with the best Prepared Environment, if the adults are not excited about the natural beings, neither will the children be.

Child looking at spider web