Have you ever had a bowel of ramen? Not the noodles that come in the plastic package but the Japanese soup bowl of noodles with broth, vegetables and other things.
This week, you are going to plant two crops that you could use in your own dish of ramen: bok choi and onions.
When you combine different ingredients into one dish, like you do for ramen or when you make a salad, you are causing a physical change to the ingredients. You cut vegetables smaller or remove the peel.
These changes effect the vegetable but they do not change its molecular structure.