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.
Preparing to Wean a Kitten. 1  1. Determine when to wean your kitten. The weaning process begins when kittens are around four weeks old. 2  2. Purchase the necessary nourishment. When you first start weaning your kitten off of its motherâs milk, youâll want to buy milk replacer. 3  3. Buy a shallow food and water dish.