Endothermic & Exothermic Reactions

Endothermic, exothermic, reaction, heat, cold, photosynthesis, oxygen, organisms, respiration.

Introduction

How can I explain this? One creates heat, the other takes in heat. But which one is which, and why do I need to know that?

Endothermic Reaction

Imagine you have an ice cube, and it is a perfectly formed cube. This cube just sits there and does nothing, right? Wrong. What happens is the ice melts. You can physically see this happen, as you will see water appear under the ice cube.

This is present in photosynthesis in plants. How? Well, the plants absorb the sunlight and turns it into energy, while it processes oxygen from the carbon dioxide the plants receive from the air.

This process is an endothermic reaction.

Interesting fact: if you place an ice cube from your freezer on to a worktop surface and place a thermometer beside it, you can visibly see the temperature increase and decrease.

Exothermic Reactions

So, you've learnt about how photosynthesis involves an endothermic reaction by ingesting heat and sunlight in the process of photosynthesis. But what about an exothermic reaction?

Well, there are examples that involve an exothermic reaction too. Let's have a closer look.

An exothermic reaction is where an object gives off heat. It can be as simple as a fire. This gives off heat, and the more oxygen you give it, means the bigger it will get. Remove that oxygen though, and you can put it out. But how does this work in a plant?

Respiration. When a plant respires, it produces energy, and this energy is a chemical process that takes place inside every cell in any and every living organism. This in turn creates heat.