Imagine the break of dawn or the onset of dusk, when the sun is just about 6 degrees below the line that divides the earth and sky – the horizon. At such times, the sky paints a picturesque image, and the brilliant majesty of the stars can be seen under optimal atmospheric situations, such as when there’s an absence of moonlight or other sources of light. During these periods, ordinary outdoor activities can still take place easily. This is because, although it is twilight, there’s still enough natural luminescence to conduct regular activities.
Dawn or dusk continues to evolve, and there’s a period when the sun descends between 6 and 12 degrees below the horizon. This time, the horizon is still well-defined and it is possible that silhouettes of objects may be discernible without any need for artificial lighting. That said, it becomes challenging to partake in routine outdoor activities without some form of added illumination to supplement the diminishing natural light.
There is a time during sunrise or sunset when the sun is situated between 12 and 18 degrees underneath the horizon. At this juncture, the sun ceases to provide any considerable light to the atmosphere. You’d expect this before the sun shows its first light in the morning, or after it tucks away in the evening. As dawn turns into full blown morning or as dusk gives way to full night, the sky’s illumination turns quite dim, to the point where it might be barely noticeable or completely vanish.
Temperature is an interesting scientific concept that deals with the assessment of how hot or cold something is, based on a particular benchmark. It is quantifiable and can be measured in various units such as Kelvin (K), Fahrenheit (F), and Celsius (C). Regardless of which unit you use, what is common is that temperature serves as a measuring stick for the level of heat or coldness in an object or a substance.
Exploring the concept of wind, it is essentially air in motion with reference to the earth’s surface. Originating from discrepancies in atmospheric pressure, wind comes into existence when areas of high and low pressure confront each other. This dynamic sets up what is known as a pressure gradient force, which leaps from a region of high pressure to one with low pressure, driving the movement of air.
This force due to differences in pressure, is responsible for the creation of wind, making it gust in the direction corresponding to the pressure gradient. The greater the variance in pressure, the more substantial the force, which in turn results in a more potent wind. To describe wind, we talk about the primary direction from which it’s blowing, along with its speed typically calculated in units like miles per hour or knots.
Atmospheric pressure is the force exerted as a result of the weight of the air above us and the constant pull of earth’s gravity. This pressure can be represented in different units based on specific domains or fields. These include atmospheres (atm), millibars (mb), pascals (Pa), inches of mercury (in), and pounds per square inch (PSI) among others. But when it comes to weather forecasting, meteorologists tend to use millibars more often than not.
Let’s talk about rainfall, which is the amount of rain that falls over a designated duration. This could range from daily, monthly, to yearly measurements. These measurements are crucial for a number of calculations and forecasts, from weather prediction and water management, to agricultural planning and climate study. The process of rain measurement is simple but has a significant impact on various sectors of life and science.
The electromagnetic spectrum is an all-encompassing range that contains all possible frequencies of electromagnetic radiation. One intriguing segment of this spectrum lies between 5 – 400nm. While invisible to the naked eye, this part of the spectrum plays a pivotal role in various fields including astronomy, telecommunications, and medicine.