Activity 5 Lec | Relevance of Studying the Properties of Waves

        Conducting studies about waves allowed us to understand the different phenomena happening around us. Scientists were able to create theories and apply them to design varieties of inventions. This phenomenon can be natural like the occurrence of earthquakes. We can now detect the location, depth, and magnitude of an earthquake because we already know the properties and nature of the movement. Radars are also used to detect meteorological activities such as typhoons. These innovations help us to prepare and secure ourselves and properties from different calamities. Moreover, it also helps us experience a convenient way of living through easier communication, food preparation, and transport of goods. It also provided us the luxury of time with entertainment and shortened our time with our daily chores. In the field of medicine, it prolonged the life of humans with the continuing advancement of medical technology. With this, we can now examine and treat every corner of our body, inside and out. Indeed, research and study on the properties of waves able us to unfold the technological breakthroughs we have today. Our responsibility, for now, is how to balance the pros and cons of these discoveries on our own hands.

Activity 3 Lec | Electromagnetic Waves

If there is an explosion in the moon, is the sound can reach the Earth? What about the light/fire from the explosion, can you see it from Earth? 

          Any sound from the space cannot reach the Earth. A sound is a form of a wave that creates the sensation of hearing. To make this possible, it needs a medium to travel. Sound travels by the help of the molecules present in the medium (e.g solid, liquid, and gas) This means a sound cannot travel in an empty space, no air, otherwise known as the vacuum. Since a vacuum does not have any medium then it does not also have any molecules that will aid the sound travel. To answer the question, space is an example of a vacuum. The sound of an explosion coming from the moon cannot travel across Earth because of the absence of a medium. Light, on the other hand, can travel in space. It is just that explosions happening in the moon are too weak. They appear fainter from Earth because of the distance and gases which makes it impossible to see with our naked eyes. Astronomical instruments are needed to see one. 

The distance from the Earth to the sun is 150.51 million km, but why we can feel its radiation?

         The radiation emitted by the Sun is called ultraviolet radiation. This radiation can travel through a medium or a vacuum, making it possible to travel in space. The radiation is consists of tiny and massless packets of energy called photons. Photons can travel smoothly through space that whenever they hit any object like Earth, they get absorbed and impart heat energy. Our atmosphere also played an important role in trapping 50% of the sun's energy and preventing it from reflecting back into space.

Why cell phones are still used today and considered non-harmful? Is it really not harmful to humans?

        Cellphones use microwaves for signals. In the electromagnetic spectrum, microwaves are categorized as non-ionizing. They emit a low level of radiation which makes it safe to use. FDA believes that the weight of scientific evidence has not linked exposure to energy from cellphone use with any health problems. However, it is important to note that extensive exposure to radiation may lead to danger. Responsible usage of such should be practiced because our body has its limitations from radiation.

Why EM waves are generally harmful? Or is it really harmful?

         Electromagnetic waves are not generally harmful unless we are extensively exposed to it. Our body has its natural way to eliminate toxins accumulated in a specific length of time. This will only affect us negatively when accumulated beyond the dosage limit.