Activation Energy:This is similar to your initial energy spent climbing up the hill. It’s the minimum amount of energy required for reactants to form products in a chemical reaction.
Reactant/Product: These are what you start with before climbing/the path you create after descending from your hilltop journey. Reactants are substances present at start of reaction while products are formed at end of reaction.
Catalyst:A catalyst would be like having hiking gear for your climb – it helps lower activation energy needed for reaching transition state.