When you enter a chemistry lab, on the bench, there are some bottles containing chemicals, and some of these chemical bottles are tinted so that they have a dark brownish colour. My chemistry teacher had told the class that the dark colour is used to prevent light from getting to the chemicals stored in the bottle, so that the chemicals will last longer. But I don't understand why. Let's say the bottle is not tinted and clear, the light will get to the chemicals, which is common sense, and provide energy for the chemicals to decompose or react. Now let's say the bottle is tinted, the most of the light that falls on the bottle will be absorbed by the bottle, 'cause dark colours absorb more light. And the energy absorbed from the light will then be transfered by conduction to the chemicals, cause there will be a energy gradient between the chemical and the bottle. So in the end, it's all back to square one. So how does making the bottle dark in colour actually help in anyway? My physics is not the greatest, please point out any flaws in my physics.