The Voice Print Technology

This week, we all did a presentation on a topic of our choice by “Applying Waves & Sound to Design”. I talked about voice print and how it related to our unit, the main uses of it, the impacts it has on society, careers involved, and the new research being done to improve this technology. I wanted to further explain voice printing and give you links if you are interested in discovering the many sides to the voice print technology.

What is voice print? 

Voice print can be defined as a set of measurable characteristics of a human voice that uniquely identifies an individual. 

In accurate voice printing, frequencies and amplitudes are measured, factoring in intensity, pitch and tone.

An example of voice printing, a spectrogram of an actual violin playing. Credits:

Main uses of voice print (click on each link for more info):

The voice print technology is used for many more different things in our modern world, but the list could go on and on. Since, the voice print technology is found almost anywhere, it has positive and negative impacts to our society. Voice printing is a very useful tool to help identify callers as suspected fraudsters, but it is not impossible to get past the system, if their voice printing technology is not up to date.

If you are interested in voice print technology and want to explore it in the future, to maintain and research about it, there are different majors that can lead to a career in the voice print technology. Click here!

Research is continuously being done for this technology, people around the world are finding new ways to use it. Watch this really cool video where a 3-D voice print of Obama’s voice is played.


Interference of Waves

Imagine the surface of a lake on a day that is windy, many wave motions are visible. Even though it may not look like it, these waves are moving in different directions, with different wave lengths and amplitudes. When the waves meet, a new wave is formed, this is called interference. When waves meet and interfere with each other two things can happen, depending on what kind of waves are involved.

So what does interference mean?

“Interference is the process of generation a new wave when two or more waves meet.” (Nelson Physics 11 9.1) 

Watch this very helpful video on how different waves interfere to produce new waves: 

Recall that:

Constructive interference can be defined as “the process of forming a wave with a larger amplitude when two or more waves combine.” 

Destructive interference can be defined as “the process of forming a wave with a smaller amplitude when two or more waves combine.” 

It is important to remember that when a crest and trough interfere, they produce a smaller wave. When a crest interferences with another crest, this will produce a larger wave. To practice and understand how the interference of waves work, follow the examples in the Nelson Physics 11 textbook on page 417 below and do 9.1 question #2. 

Crest interfering with trough

Crest interfering with trough

Crest interfering with crest

For more information read: The Physics Classroom: Interference of Waves (try out the questions at the bottom!). 

How Do Elephants Communicate?

Last week, I talked about how sound waves are very important to humans throughout our everyday lives, whether it be for communicating by speech, listening to music, or being aware of what is around us. Not only is sound important to humans, but animals also rely on the use of sound and the waves of sounds to survive in their environment. When you think about animals and their use of sound waves, I’m pretty sure you would be thinking of dolphins that use echolocation or may be bats that are practically blind, but I’m sure you have heard lots about those animals. I wanted to talk about a different animal that many may not know about and how they use sound waves to survive in the wild and communicate to one another.

Elephants are the largest land animal in the world, the largest elephant on record was an adult male African elephant weighing at about 24,000 pounds! As with their size, they have the largest brain of any land animal and behaviourally show a very high degree of intelligence. A large portion of their brain is focused on the ability to hear, many people assume that elephants have good hearing because of their very large ears, but those large flaps on their ears called pinnae are just useful for cooling themselves and showing different moods.

An African elephant (Credits:

An elephant’s hearing receptors are placed under their trunks and feet. Many elephants that have been observed, placing their trunks against the ground showing that they are trying to detect sounds. They may also lift up one foot to place more pressure on the other three, so that it is firmly against the ground. Elephants do these things because elephants can send sound waves through the ground that other elephants are able to detect (elephants are able to send sounds through ground and air). These sounds are at very low frequencies called infrasound which is at 15Hz to 35Hz and these sounds can be as loud at 117dB. These sounds are able to travel very far, up to 10km!

Watch this video for more info:

 Interested in this amazing creature? Read some facts about it here! 

What Does Sound Look Like?

Before I show you what sound looks like, I want you to understand what sound is. In the Oxford Dictionary, sound is defined as:

“vibrations that travel through the air or another medium and can be heard when they reach a person’s or animal’s ear”

We are able to sense vibrations, these vibrations are all around us, from a beat of a drum to dropping a book on a table. These are all vibrations, vibrations can cause disturbances that move away from the source in a form of waves. Sound waves travel through the air and are a result of pressure variations from different points. Waves can be considered to be the motion of a disturbance.

The sense of hearing is very important to us humans throughout our daily lives, without sound we would not be able to communicate by speech, listen to music, or be aware of our surroundings. Since, sound is very important to us we must understand the properties of sound.  Sound waves have three different categories that cover the different ranges of frequencies.

Audible sound waves are in the range of sensitivity of the human ear (20Hz to 20 kHz).

Infrasonic waves have frequencies below the audible range (ex. earthquake waves).

Ultrasonic wave have frequencies above the audible range for humans (ex. ultrasound imaging device).

Scientists have figured out experimentally that the speed of sound through air depends on the density of the air and the temperature. The value would be increased by 0.606m/s for every increase in temperature by 1ºC.

v = 331.4m/s + (0.606m/s/ºC)

Now that I have told you some general facts about sound, I will show you what sound looks like! If you watch this video you will be able to see sound.

It is important to know that even though sound is an amazing thing that exist in our daily lives, we can also hurt our eardrums and the ability to hear as a healthy human being. Any sound levels that are greater than 100dB that goes on for more than a few minutes will harm your hearing. You must realise that the louder a sound is, the less time you should be spending near whatever it is, to ensure that you do not damage your hearing. If you work in an environment that is always very loud, be sure to wear hearing protection or equipment that will protect you from hearing damage.


These are the values on how long you should be exposed to each dB of sound. It is evident that the times dramatically lower, as sound becomes louder. Credits : Nelson Physics 11 p. 396

The gift of hearing and sound is great, be sure to protect your hearing at all times!

What Will Earth Look like in 250 Million Years From Now?

We all know that Earth did not always look like what it did today, but if this is new information to you then let me explain: Earth has been around for about 4.54 billion years and in the beginning the continents of Earth weren’t always where there are now (click here to see the evolution of Earth). Earth’s land masses has always been in constant motion, the plates under Earth’s crust and convection currents are the reasons for this.

Ron Blakey’s maps of the paleotectonic evolution of North America. Credits:

As you can see, North America was not always separated or more scattered apart, we also did not always have all of our green land like we do today. In the very beginning of Earth’s time, our land was all close together and our planet experienced ice ages and extreme heat conditions (we still see that today, just not as severe or constant throughout the year).

To understand why Earth has been changing you must know the definition of convection current and how it works.

Convection occurs when colder, denser fluid falls and pushes up warmer, less dense fluid. You can visually see how this works in this video (and/or try the experiment out!):

Water that is warmer will have particles that move quickly and spread further apart, the water in the bottom bottle is more dense than the water at the top. Resulting in, the denser water (cold water) below the less dense, warmer water staying at the top and the two colours of water do not mix. Once the cold water is placed at the top we can see that the colours mix, since the cold water is more dense compared to the warmer water gravity pulls the denser water downward, while the less dense, hot water travels upward.

The second factor to understanding Earth’s constant changes, you must have an idea on plate tectonics.

If you watch this video, it will explain plate tectonics and how it relates with convection currents under Earth’s crust.

Once you have understood these two factors, I am sure that you must believe that the Earth has been and will always be constantly moving under us. It is interesting to see that many million years from now, Earth will look different again, to myself that is quite unbelievable that the lands will always be changing. This makes me think that a lot of things will change in the future, like travelling. Imagine if our lands we’re coming closer together and some continents started pushing up against each other… Imagine our world map, how different that would look, I think that this is fascinating and every day geologist are putting their research into amazing possibilities, sorting out satellite images for us and predicting what the future has in store, which is helping us learn about the amazing Earth that we are living on. If you are interested in this topic you can find more information about Ronald Blakey’s research, along with other geologists at this link. 

The Law of Conservation of Energy

Energy is found everywhere in our universe, we use mechanical energy to do mechanical work every day. All the types of energy in our universe involve kinetic energy, potential energy or both. Some examples of energy are radiant energy, electrical energy, thermal energy, sound energy, etc (Fig. 1). Some many be worried that one day there will be no more energy in the universe, but it is proven that we will never run out of energy, in the sense that the energy we use will not be destroyed or created, this is called The Law of Conservation of Energy.

Fig. 1 There are many different types of energy, we experience many of these types in our every day lives. Credit:

What is The Law of Conservation of Energy?

This law is defined as the “energy that is neither created nor destroyed; when energy is transformed from one form into another, no energy is lost.” 

The total amount of energy in the universe never disappears, while new energy cannot be created out of nothing. The energy that is present can only be changed from one form to another. When this energy transformation happens no energy is lost, one form of energy is reduced by the same amount that the quantity of the other form/forms is increased, meaning that the total amount of energy stays constant.

For example, a light bulb (Fig.2) turns 100 J of electrical energy into 5 J of radiant energy and 95 J of thermal energy (side note: which is not very efficient!). This shows that no energy has been lost because 95 J + 5 J = 100 J. ( Nelson Physics 11 p. 237)

Fig. 2 The inefficient incandescent light bulb. Credits:

Not only is understanding The Law of Conservation of Energy very important, we must understand the factors in dealing with this law, that is potential and kinetic energy.

Potential energy is a form of energy an object possesses and this can be described as “stored” energy.

Kinetic energy is the form of energy an object possesses due to motion.

Watch this video to understand how kinetic energy and potential energy works with the law. 

Once you have understood the law and how it relates to potential and kinetic energy, you have the ability to use the formula:

Em = Eg + Ek  ( total mechanical energy = potential energy + kinetic energy) 

This formula will help you solve problems that relate to the law of conservation of energy by finding the total mechanical energy at one point in motion of the object and relating it to the total mechanical energy at another point.

All about work & MORE!

This week in class we started our new unit called Energy and Society, we started the unit talking about work and how we calculate work. I wanted to create a little note for you to summarize some key things you should know and remember.

W = ∑FΔd


  • Work is being done only when a force displaces an object.
  • The unit for work is Joules (J) named after James Joules. 

    Credits: Nelson Physics 11 pg. 225

    Credits: Nelson Physics 11 pg. 225

  • If a force is applied on an object, but the object does not move, there is no work being done (Physics 11 page 223).
  • 90° motion equals no work, while the object may be displaced the object is not the one that is affected by the force, for example carrying a backpack on your back, while walking to class. While you are moving the bag would also be considered displacing from one place to another, but this force is not place on the bag. (Fig.5)
  • When there is work, there is acceleration.

Mechanical work is calculated using the equation:

W = ∑F(cos θ ) Δd

If the forces acting on a object in a direction opposite of the object’s displacement, θ would equal 180° meaning that cos θ = -1. The equation W = ∑F ( cos θ ) Δd becomes W= ( ∑F Δd ) (-1) and the amount of work is a negative value.

I also have this video that is very informative and seems like it would help us throughout this unit. It has some information on what work is and “how work…works”, but there is also some extra information on energy and power, which we haven’t gone through yet or learnt, but I was looking ahead of the chapter and saw that we will be learning some of these terms and thought it would be helpful if we were all to have a general idea on what power and energy is all about! I hope that this video will help you during this chapter!