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.
Babies can generally be weaned at about 3 weeks of age, but it is always better to allow them to wean on their own, which shouldn't take more than a week or two longer.n an average, bucks are weaned at 3-4 months, does are weaned 4-5 months. However, left to their mot â¦ her's discretion, a mother goat allows the baby to wean naturally and longer than humans will. 3 people found this useful.