Everyday importance of light

Why are you reading in the dark like that, Michael? How can you even see anything in that book?! Jenny is right, it is hard to see in the dark. During the day there is enough light reaching your eyes so you can see. You usually don't have to turn on the lights to see things around you.

But when you enter a dark room, or when night falls, your eyes can't distinguish objects immediately. They need to adjust first. And if it’s really dark, you can’t see anything until you turn on the light. Light plays many other roles in our daily life too! Let's shed some light on that thought!

Throughout the ages, people have lived according to the natural cycles of day and night on Earth. In many ways, our bodies have become dependent on those cycles, and on light itself. Think for a second - when do you have most energy? It’s probably during the day, when there is plenty of light! But as the sun sets and night approaches, you most likely start feeling sleepy or less energetic.

This is because your body reacts to the amount of light, causing your brain to produce substances, that prepare you for sleep, or to keep you awake. In this way, light regulates your biological “clock” - the circadian rhythm. Light is also very important for your physical and mental health. How? With the help of ultraviolet radiation from sunlight, cells in your body produce Vitamin D.

Vitamin D is important for keeping your bones healthy and strong. Lack of sunlight can actually be quite bad for you. Scientists observe that during seasons when there is less light, people can experience low energy. Even their sleeping or eating habits can change. This is known as seasonal affective disorder or SAD.

Scientists argue that lack of light might be one of the main reasons for SAD. Apart from helping our physical and mental health, light is an important part of our daily lives. Lamps, cellphones, laptops, TVs... Thanks to electric light bulbs and other artificial sources of light like these, we can continue with our lives even after the sun sets. Light is often used to communicate or signal something too.

Think of traffic lights - simple messages such as “stop” and “go” are communicated through the use of different coloured lights! Light can also be used to affect our productivity, concentration, or feelings! Places where you need to focus, such as schools or offices, are usually brightly lit. This helps us concentrate, and achieve better results. Very harsh light can make you experience emotions intensely, and even cause you to make hasty decisions, such as buying things you don’t need.

On the other hand, warm ambient lighting makes us feel relaxed and cozy, so it is often used in places like restaurants. Although it’s hard to imagine modern life without light, using artificial light has its downsides too. Too much light can strain and hurt human eyes, or cause sleep problems. Excessive artificial light can affect nature too. For example, many animals that are active at night get confused by bright lights in cities.

They can't tell night from day, and as a result they don't know when to go and find food. Animals that use light to navigate at night, such as moths, often can’t find their way either, when there is bright artificial light. Light helps us feel good, stay healthy, and enjoy our daily lives, but sometimes we need to turn the lights off! Doing this helps us rest, and it saves energy, which helps the planet, too. Oh, well, it’s time to go to bed anyway!

Lights out!