If you like your Physics and you like your Chemistry,
You will find this puzzle, as easy as can be.
Firstly, from a glass of milk, take what is good for bones.
Second take the metal used to glaze pottery with pretty tones.
Thirdly you might eat me to get your innards on a slide;
Last I am a diode in a "crystal-set" just look inside.
Now put us all together, and thus what can be seen?
A great big head? ; A large white moth? ; A vegetable that's green?
What am I?