Do Now 1. How can a flame test be used to identify an unknown element? 2. Why did each element in this experiment produce a different color flame? 3. What is the correlation between the color that an element produces and the amount of energy that is being released? 4. Did you see any trends between the amount of energy released and periodic period or family?
Making Waves in Chemistry!
WAVES!!!!!!!!!!! AYO WAVES!
Today’s Game Plan Do Now10 minutes What is a Wave and the Electromagnetic Spectrum? 5 minutes Work it Out!5 minutes Wavelength and Frequency15 minutes Work it Out!10 minutes Independent Work Time15 minutes
Defining a Wave Wavelength - distance from CREST to CREST Frequency - cycles per second; how many crests pass a given point in a second
Electromagnetic Radiation Electromagnetic Radiation: Energy that travels in waves at a speed of 3.0x10 8 meters/second
Electromagnetic Spectrum Different types of electromagnetic radiation are depicted on the electromagnetic spectrum. Wavelength in meters x x Gamma rays X-rays Ultraviolet Infrared Microwaves Radio Waves FM Shortwave AM Visible Small Wavelengths Long Wavelengths High Energy and Frequency Low Energy and Frequency
Today’s Game Plan Do Now10 minutes What is a Wave and the Electromagnetic Spectrum? 5 minutes Work it Out!5 minutes Wavelength and Frequency15 minutes Work it Out!10 minutes Assign Homework and Independent Work Time 15 minutes
Whiteboard Time! Check out the Electromagnetic Spectrum in your notes to answer the following questions… 1. What type of electromagnetic radiation has the longer wavelength, television or ultraviolet? 2. What type of electromagnetic radiation has the largest frequency? 3. What color in the visible spectrum has the longest wavelength?
Today’s Game Plan Do Now10 minutes What is a Wave and the Electromagnetic Spectrum? 5 minutes Work it Out!5 minutes Wavelength and Frequency15 minutes Work it Out!10 minutes Assign Homework and Independent Work Time 15 minutes
What is the relationship between wavelength and frequency?
Which of these waves has the greatest frequency?
Relationship between Wavelength and Frequency As the wavelength increases, the frequency decreases As the wavelength decreases, the frequency increases
Speed of light=frequency x wavelength C = f C: speed of light 3.0 x 10 8 m/s We have an equation to relate wavelength and frequency
Speed of light=frequency x wavelength C = f f: frequency (units are Hz) We have an equation to relate wavelength and frequency
Speed of light=frequency x wavelength C = f : wavelength (units are meters) We have an equation to relate wavelength and frequency
Let’s Try One! C = f Determine the frequency of light with a wavelength of x m. Given:Work: C = 3.0 x 10 8 m/s f= ?? = x m C = f (3.0 x 10 8 m/s) = f ( x m) f = (3.0 x 10 8 m/s)/( x m) f = x Hz
Calculator Mini-Lesson How do I do this????? Determine the frequency of light with a wavelength of x m. In your calculator… (3 x 10 8 ) / (4.257 x ) Your graphing calculator does not understand order of operations You must put in parentheses!!!
Let’s Try Another! C = f Green lights on a traffic light have a wavelength of 5.23 x m. What is the frequency? Given:Work: C = f= = C = f
Let’s Try Another! C = f Green lights on a traffic light have a wavelength of 5.23 x m. What is the frequency? Given:Work: C = 3.0 x 10 8 m/s f= ?? = 5.23 x m C = f (3.0 x 10 8 m/s) = f ( 5.23 x m) f = 5.74 x Hz
Let’s Try Another…Last Time….Seriously! C = f A photon of light has a frequency of 8.4 x Hz. What is the wavelength of the light in meters? Given:Work: C = f= = C = f
Let’s Try Another…Last Time….Seriously! C = f A photon of light has a frequency of 8.4 x Hz. What is the wavelength of the light in meters? Given:Work: C = 3.0 x 10 8 m/s f= 8.4 x Hz = ?? C = f (3.0 x 10 8 m/s) = ( 8.4 x Hz) = 3.6 x m
On your own… 1. Define frequency and wavelength 2. Draw a picture of a wave and label 1 wavelength 3. What is the equation used to determine frequency and wavelength? 4. What unit is used to measure frequency?
Quantum Theory Einstein Concluded - light has properties of both waves and particles wave-particle duality “wave-particle duality” Photon - particle of light that carries energy
Quantum Theory E:energy (J, joules) h:Planck’s constant ( J·s) f:frequency (Hz) E = hf The energy of a photon is proportional to its frequency.
Quantum Theory Example: Find the energy of a red photon with a frequency of 4.57 Hz. GIVEN: E = ? f = 4.57 Hz h = J· s WORK: E = hf E = ( J· s ) ( 4.57 Hz ) E = 3.03 J
We have now learned two equations: C= f E = hf If we have wavelength we can find energy….how?
On your desk… Determine the energy in joules of a photon with a wavelength of 3.45 x m
Today’s Game Plan Do Now10 minutes What is a Wave and the Electromagnetic Spectrum? 5 minutes Work it Out!5 minutes Wavelength and Frequency15 minutes Work it Out!10 minutes Independent Work Time15 minutes
Today’s Homework Electromagnetic Spectrum and Light W.S. (front and back)