The three period lesson is a classic Montessori technique for teaching the names things. When combined with geometric solids, you have a sure fire hit with younger learners.
All you need is a set of geometric solids like shown in the image and this lesson.
Period One: Name It
Say, "This is a sphere. Would you like to say the word 'sphere'?"
Emphasize the ssssffff sound when you say the word. Children usually do want to practice saying it a few times. It feels funny on the tongue.
Roll the sphere between your hands. Hold it up to your cheek. Pet it with the tip of your finger. If you want children to treat the materials as if they are precious, you must also act as if they are all made of the finest crystal.
Offer the sphere to the child. "Now it's your turn to hold the sphere."
Period Two: Play With It
Point to the sphere. Does the sphere roll? It does! Put the sphere on top of your head. Put the sphere on my elbow. Give me the sphere. Where is that sphere hiding? Oh! The sphere was in my lap! <giggle> (Nobody said that the three period lesson had to be dull!)
Period Three: Recall - Can the Child Tell You Its Name?
Ask, "What is this?" If the child doesn't know the name of the sphere by now, don't worry. You just need more playtime with it. Put it away for now and get it out again later and re-do the lesson. No worries.
Period three is just about checking to see if the child can remember the name. If your child doesn't seem interested in the lesson, maybe now is simply not the time to teach the concept. Back it goes on the shelf for a few days, weeks, months, or even a year. It's all good.
Teach Respect for the Materials
Almost inevitably, children recognize the sphere as a ball, and they may be inclined to throw or roll it off the rug. Just before this happens, acknowledge that the sphere is definitely like a ball and that actually, a ball is in the shape of a sphere!
But our sphere is not a ball. It is special. Our sphere. It isn't for throwing. It's special. It stays on the rug. If it is intentionally rolled away or thrown, you may suggest that the work be put away in lieu of a sphere that is for throwing - a bouncy ball in the yard, perhaps?