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.
The guidelines also state (for those parents who might be tempted to wean extremely early) that no baby should be started on solids before the age of four months (17 weeks). This, of course, is not the same as recommending you start your baby on solids at 17 weeks.he guidelines also state (for those parents who might be tempted to wean extremely early) that no baby should be started on solids before the age of four months (17 weeks). This, of course, is not the same as recommending you start your baby on solids at 17 weeks.