Chemical reactions and catalysts. A chemical reaction involves a chemical change, which happens when two or more particles (which can be molecules, atoms or ions) interact. For example, when iron and oxygen react, they change to a new substance, iron oxide (rust).
It's important for parents to start weaning babies from bottles around the end of the first year and start getting them comfortable drinking from cups. The longer parents wait to start the transition, the more attached kids become to their bottles and the more difficult it can be to break the bottle habit.
Talk with your caregiver about the best time to wean your baby. 1  Introducing solid foods: Weaning should begin when your baby is about 6 months old.  Weaning from breast milk: Your baby needs nutrients from breast milk until he is at least 12 months old.