Posts Tagged ‘waves’

Exam review

Friday, May 20th, 2011

Check out this post by Mr Goodman for some good resources on reviewing the Waves topic.  And here is a list of interactive websites for review:-

Bonding

Ionic compounds

Naming compounds

Atomic structure, atomic number and mass number and isotopes

Periodic table Jeopardy

Atomic models quiz

Balancing equations battleships

Series of games on naming ionic and covalent molecules

Organelles and cell structures

 

 

Refraction

Friday, April 29th, 2011

refraction by the_green_squirrel

All waves refract.  This means that they change speed as they travel from one medium to another.  For example, light waves travel faster in air than they do in water.  This means the pencil in the glass of water looks like the picture on the right.  For a full explanation of refraction, read this.  Hopefully you now understand the concept.  If not, ask this archer fish to explain it to you!

We will do a lab to investigate refraction of light as it passes through glass and perspex, and to determine the refractive indices of these substances.  This handout (thank you Mr Duckworth) explains in more detail. Grade-9-Integrated-Science-Waves-Topic-refraction1

You will be required to submit the data tables, calculations and graphs for this lab only.  Refer to this rubric: FINALRubric DCP

Electromagnetic Spectrum

Monday, May 24th, 2010

800px-EM_Spectrum3-new from wikimedia

Log on to this great site.  Read through the information and general background on the home page.  Then click through the different parts of the spectrum from radio waves to gamma rays and discover how each is made as well as their uses and dangers. 

Summarize the information in any format you choose (word document, prezi, glogster, powerpoint, podcast, vimeo, animoto).  Enjoy!

Here are some examples of the great work you have produced: EMS-Bianca    Nish.The Electromagnetic Spectrum!    Sandy.The Electromagnetic Spectrum

Reflection

Tuesday, May 18th, 2010

car side mirror reflection by just_a_name_thingie on flickr

You are going to investigate reflection in a plane (flat) mirror.  You will use the apparatus provided to collect data to support your findings.  You will be required to present the data in tables, and then to process it appropriately.  Make sure you look at the previous lab on refraction, and don’t make the same mistakes! 

Here is an outline from Mr. Duckworth that explains in a bit more detail what you need to hand in.  REFLECTION LAB

Application of lenses

Thursday, May 13th, 2010

telescope by Waifer X on flickr

Here are links to a couple of sites on ray diagrams.  This first one is factual.  This one is interactive, and covers the different types of image obtained when you place your object various distances from the the lens. 

Make sure you know the difference between a real and virtual image, an inverted and an upright image, and a magnified and diminished image.

Now that you know all about refraction, and how light bends as it passes through lenses, it’s time to take a look at where we use lenses in our daily (or not so daily) lives.  Microscopes, telescopes, cameras, binoculars, all contain at least one lens.  Your task is to select one application of lenses and do some research on it.  Prepare a glogster poster of your findings.  You must explain what type or types of lenses are present, what refraction has to do with your chosen application, and how it works.  Follow the links here to help get you started.

Refraction of light

Monday, April 19th, 2010
refraction by Moh_Tj on flickr

refraction by Moh_Tj on flickr

We’re going to learn about refraction and how it happens.  Thanks to Mr Duckworth for producing these notes to help us. Grade 9 Integrated Science Waves Topic – refraction  

We’ll also be doing a lab to collect some data and find out the refractive index of glass and perspex.  The rubric is here: Pre IB Lab Rubric 08 – 09  You will be assessed on the data collection and processing part only.

How we hear

Friday, March 26th, 2010
Malayan Flying Fox 2 by littleREDelf on flickr

Malayan Flying Fox 2 by littleREDelf on flickr

Sound waves travel through the air, and we are able to detect them, using our ears.  So, let’s start by looking at a diagram of the human ear, and relate the structure to the function.  You don’t need to be able to draw the diagram, just label it, and know what each part plays in allowing us to hear.  Use this site to learn about ear structure and how we hear. 

Now let’s try and answer these questions:-

  • Why do we have two ears?
  • What is perfect pitch?
  • How do cochlear implants work?
  • How is an owl’s face like a satellite dish?
  • What is ultrasound?  How do we use it?
  • What is echo-location?  Bats and dolphins use it all the time. Can humans learn to as well?

Thanks to Mr Boulton for finding these resources.

Earthquake in Manila!

Thursday, March 25th, 2010
location of earthquake from USGS

location of earthquake from USGS

As if we arranged the whole thing… following on from this week’s discussion about earthquakes, seismic waves, epicenters, S and P waves…did you feel it

Could you explain to your parents (assuming they are not seismologists) what happened to cause today’s quake?  Could you explain it to someone in Grade 1?

Was there a tsunami warning after this earthquake?  Why or why not?

Waves on the Earth

Thursday, March 25th, 2010
Tsunami Hazard Zone by hey mr glen on flickr

Tsunami Hazard Zone by hey mr glen on flickr

These are some of the questions we should be able to answer after some research.  Check out these videos that explain a bit about earthquakes.  This one relates sound waves to earthquakes.  This one relates transverse and longitudinal waves to earthquakes. 

  • How are water waves formed?
  • Why are earthquakes so damaging?
  • How are tsunamis created?
  • Why do some indigenous tribes place their ears to the ground to hear if someone is approaching?

Waves questions

Wednesday, March 17th, 2010

The distance between repeating parts of the pattern (the length of each single wave) is known as the wavelength (l).  Wavelengths can be measured from anywhere to the next identical part of the wave.

Frequency is a measure of how often something happens in one second. The symbol of frequency is f and the units are hertz (Hz). The relationship between velocity, frequency and wavelength is:

 Velocity (m/s) = frequency (Hz) x wavelength (m)

Light waves travel much faster than sound waves. The speed of a set of waves can be found by using information about the distance travelled and time taken or from information about the frequency and wavelength.

Distance, speed and time are connected by:

Speed (m/s)   =   Distance (m) / time (s)

Example An echo takes 1.5 s to reflect from the front wall of a school building 250m away. What is the speed of sound in air?

Distance for echo = 2 x 250 m = 500 m                                Time taken   = 1.5 s

Speed = distance/time = 500/1.5 = 333m/s

This method is practical at school only for the measurement of the speed of sound.

Example Capital Radio broadcasts throughout the London area using radio waves of frequency 1548kHz, travelling at 300000km/s. To what wavelength would you tune a radio to receive Capital programmes?

Speed   = 300000km/s = 300000000m/s                  Frequency = 1548 kHz (1 548 000 Hz)

Wavelength = speed/frequency  = 300 000 000/1 548 000 = 194 m 

Using your knowledge of the wave equation, and the relationship between frequency and time [f = 1/T], answer the following questions:-

  1. If the waves in the ocean are timed so that they come to shore every 1.74 seconds, what is the frequency of these waves? (Show your working and don’t forget units).
  2. A radio wave has a frequency of 2 MHz (2 MegaHertz = 2 000 000 Hz). Calculate the time period between successive waves.
  3. A radio station broadcasts with a wavelength of 160m. If the velocity of the radio signal is 3 x 108 m/s, calculate the frequency of the wave. 
  4. If all the 1.2 billion people in China jump up and down at the same time, they will create a shock wave that will travel around the Earth in all directions.  This wave will focus and peak on the other side of the Earth, exactly opposite China (around California).  If the circumference of the Earth is 40 000km and the speed of sound on the Earth’s surface is 2850m/s, calculate how long it will take for California to crumble into the sea due to the shock wave.

Grade 9 Integrated Science 1 docwaves practice questions mark scheme