Types of Waves, Mechanical & Electromagnetic Waves

Earth is full of unbelievable science pieces. Humans have identified many phenomenons after years of experiments and yet they haven’t identified all of them, will never be probably. Even you haven’t notice the science around you, it happens everyday 24/7. Waves are just one of them.

I have explained you 2 types of waves in a previous post. It was about transverse waves and longitudinal waves. Amazing thing is those 2 wave types belong to something that I’m going to explain now.

There are energy types which transfer as light waves and sound waves. You already know the necessity of a medium for sound waves. However, the light waves do not require any medium to travel. Heat waves are another example for that type of waves.

These waves which does not require a medium can travel even through a vacuum. Do you know satellites and space stations send information as these types of waves. Okay, finally let me tell it, they are known as Electromagnetic Waves.

Types of Waves by Medium

Previously we classified the waves by considering the movement of the particles. And now you’re going to find out the 2 types of waves according to the media of propagation.

1. Mechanical Waves
2. Electromagnetic Waves

See the following flow chart to realize how previous wave types are related to this classification of waves.

 

Types of Mechanical Waves Explained

There are many types of waves, but this type of waves require a medium to travel. Examples of Mechanical waves include many waves such as,

• Sound waves
• Water waves
• Ocean waves
• Earth quake waves
• Seismic waves

Sound Waves

Sound waves are considered as a type of mechanical waves under sub type, longitudinal waves. When talking about sound waves, there are whole lot of sounds we hear everyday from songs to horns and your voice to bird voices.

Do you know there is an energy flowing with waves? Yes, that’s why particles vibrate and why we hear the sounds. Lot of animals create sounds by vibrating vocal chords of their throat. Today communication is evolved to emails, messages and similar technologies, but the common method is sound communication.

Musicians have done amazing things by manipulating sound to build songs. You can find even crazy instruments too.

Water Waves

What happens when a stone is dropped to a bucket of water? It generates some type of wave. Remember water waves are always transverse waves under mechanical waves main type. This means particles vibrate right angled to the direction of the wave. Tsunami, floods are common destruction of water waves.

Earth Quake Waves

Earth has few layers and one of them is the lithosphere. It is broken down to tectonic plates and sometimes these plates slide inside the earth. This activity causes the earthquakes. Quick releasing of stress and energy through cracks on earth is the main reason for earthquakes.

Earthquakes happen when the cracked sea bed set again with each other due to release of energy through the process. These shock waves come to the surface of earth as earthquakes.

Epicenter is the place where it all starts. There are 2 types of waves coming from the epicenter.

• Body Waves
• Surface Waves

So what’s the bad one from above 2? What causes the painful damage to our lives? They are surface waves. They are transverse waves.

You can find 2 types of waves for body waves as Primary and Secondary waves.
– Primary waves → Longitudinal waves
– Secondary → Transverse waves

Secondary body waves got the ability of traveling through inside of earth. Earthquake waves are also known as Seismic waves and they can be identified with Seismometers.

Shallow Water Waves

This type of waves are created in the shallow water. Their circular motion turns to an elliptical motion once near the shore. Surface waves become steeper and higher. However higher depth means a weak wave which breaks quickly. That’s why the surf is formed by the crest of this type of waves.

Tsunami also a type of shallow water waves. These waves have higher wave length and a little amount of energy loses when it travels. Near the coastal area the wave length becomes small by increasing the amplitude of the wave. So it turns to be a monster wave that attack the land.

Cracks of the sea bed can often occur due to the landslides, volcanic eruptions, nuclear bomb tests under the water and meteors too.

Types of Electromagnetic Waves

Electromagnetic waves are the type of waves which does not require any medium to travel. These waves can propagate even in space too. Swing of the electric and magnetic fields perpendicular or right angle to each other forms the electromagnetic waves.

If we a draw a 3 dimensional figure to represent electromagnetic wave. Then it would have 3 dimensions as X, Y(Up or Down) and Z.

Electric and magnetic fields are widened when the speed of alternating direction of the current increases. Due to the high frequency vibration these fields release energy to the environment as waves. Unlike other mechanical waves this type of waves have different wave length and frequencies. That resulted in various properties for every electromagnetic wave.

World becomes creative and innovative day by day. Man has created various gadgets with the capability of dealing with individual electromagnetic waves. Want me to specify few examples? I’d love to do it even if you don’t want to hear it.

Televisions, Ovens, Radios, Radars, X-ray machines and many more are examples for electromagnetic waves. Before hitting some types of waves, let me describe the common characteristics of electromagnetic waves.

• Electromagnetic waves are a type of transverse waves.
• These waves do not require a medium to travel.
• As the name of the waves imply, these waves show electrical and magnetic properties.
• No any charge occur in the waves.
• Electromagnetic waves work by the laws of reflection and refraction.
• They travel as straight lines in a vacuum at a speed of 3 x 10⁸ ms^-1.
• Intensity of electromagnetic waves depend on the electrical field strength.

 

Microwaves

I’m sure your mom is familiar with microwaves better than you. Because there is a kitchen equipment using the power of microwaves. These waves have high frequency when compared to TV and radio waves. See the figure for a closer understanding of the range of these electromagnetic waves.

That kitchen instrument is the microwave oven. The magic is the microwaves can form heat in the foods kept in a microwave oven. That resulted in a quick and efficient cooking of the food better than the usual gas cooker.

Also microwaves are used in radars and for communication purposes.

Radio & Television Waves

These waves have lower frequency than microwaves and are using for communication purposes. Radios and TVs are working because of these waves. FM – Frequency Modulation – is known as the waves belong to MHz wave range while AM – Amplitude Modulation –  is known as the waves belong to KHz wave range.

I’m sure you have heard about short names AM and FM, but did you know the meaning of it? TV waves are belonging to MHz range where FM waves are located.

Infrared Rays

As you can see in the figure of electromagnetic waves, Infrared rays located in the 3rd place after radio, TV waves and microwaves. Because infrared rays have a higher frequency than those 2 types of waves. Infrared rays are similar to Microwaves a bit since they are a type of heat rays.

As a matter of fact, every hot item or gadget or object becomes cool after releasing the heat as infrared radiation. Yep! all objects become warm due to the absorption of these infrared rays.

Suppose you wanted to dry your clothes by using the energy of sunlight. You know electromagnetic waves are coming as light. Now keep the water evaporation factor aside and concentrate on drying clothes with sunlight. Here clothes get dry because of infrared rays. It’ the same reason why it gets warm too!

Photography and medical industries use infrared rays for various jobs.

Visible light

You can see the world because of the visible light waves of electromagnetic waves. Stars and sun emits visible light which includes 7 colors. You know what they have various wave lengths. Let me introduce you those 7 colors now,

1. Red
2. Orange
3. Yellow
4. Green
5. Blue
6. Violet
7. Magenta

My favorite colors are Black, Bright Yellow, Dark Red. What are yours?

X-Rays

X-rays beat all other types of waves with a ultimately high frequency. Ya! X-rays are really powerful enough to penetrate a body due to the amount of energy. That’s why doctors suggest many patients to take X-rays to diagnose various diseases such as cancers. Therefore X-rays are widely used in the medical industry.

Photographs taken with X-rays show only a shadow of what it penetrated. These waves can identify only the bones and colored tissues of animals. People use X-rays to encounter any issues with steel pipes and scientists use them as a way to see electron patterns in atoms. However these waves can cause gene mutation some times.

Ultraviolet Rays

Did you watch ‘The Strain’ TV series last month? Eph on the show uses Ultraviolet or UV rays to see those white worms. Hope you realize ultraviolet rays are used in the medical industry at that moment.

Okay tell me, do you care about your skin? Ultraviolet rays help in tanning of your skin plus synthesizing of Vitamin D. Every good thing has an evil side, excessive exposure to ultraviolet rays can be harmful for your skin and retina of the eye. Remember UV rays can be a cause for cancers.

There are substances which absorb electromagnetic waves such as Ultraviolet rays. Later these substances emit visible light to the surround. These substances are known as Florescence. I guess you have seen those florescence tube lights. Do you know how they work? Let me describe it.

The tube lights are made from glass with florescence substances applied to the inner surface of it. There is a gas inside the tube light which produces ultraviolet rays when electric current is passing through the tube. As soon as the ultraviolet rays formed they are absorbed by the florescence substances applied to the inner surface of the glass. Finally the magic gives out visible light from it.

So what you think about the Florescence materials? May be you could integrate those stuffs to do something innovative and beautiful. Humans have mixed those substances with paints, so once applied to the wall, it looks bright. There are few uses of Ultraviolet rays such as using them to kill bacteria, skin tanning, to find cracks of objects and to identify to false currencies.

It’s not the end of the world, but it’s the end of this post about types of waves according to the media of propagation. Which types of waves you like mostly, mechanical or electromagnetic? Comment your lovely opinion below and share the stuffs with your friends.