Wave Equation Notes (Page 2)

speed = frequency*wavelength

wavelength = speed/frequency

frequency = speed/wavelength

Problems (page 3)

1. A sound wave traveling through a solid material has a frequency of 500 hertz. The wavelength of the sound wave is 2 meters. What is the speed of sound in the material?

2. A student shakes the end of a rope with a frequency of 10 Hz, causing waves with a wavelength of 2 m to travel along the rope. What is the velocity of the waves?

3. A tuning fork is used to produce sound waves with a frequency of 440 hertz. The waves travel through the air at 344 m/s . What is the wavelength of the sound waves?

4. What is the wavelength of a 125-Hz sound wave when the speed of sound is 350 m/s?

5. Sound waves have a frequency of 250 Hertz (waves per second) and a wavelength of 1.30 meters. Find the speed of sound waves.

6. A wave has a frequency of 62 Hz and a speed of 31 m/s. What is the wavelength of this wave?

7. A wave has a speed of 31 m/s and has a wavelength of 31 m.  What is the frequency of the wave

8. A wave has a wavelength of 31 m and frequency of 31 Hz, what is the speed of the wave?

Refraction (Page 4)

Go to the  Bending Light  simulation here.

When light bends as it enters a different material, it’s called refraction.

1. Turn on the laser by pushing the red button.  Draw the laser, the light, and the path the light takes when it hits the material.

2. Change the bottom material to Air.  What happens when the laser strikes air?

3. Change the bottom material to Glass.  Explain what happens when the light goes from air into glass.

4. Move the protractor and measure the angle through glass and the angle through water.  Which material bends light more?

5. Explain what refraction is.

6. Click the “Prism Break” tab and add a prism (triangle) to the scene.  Turn on the laser and draw what happens in your notes.

7. Make the light “White Light” and explain what happens to the white light after it goes through the prism.

8. What color bends the least through a prism?

9. List the colors in order of longest wavelength to shortest wavelength.

Today we will study sound waves using the following simulation.  Answer all the questions in your notes.

Sound

1. Start the simulation (run now) and draw a picture in your notes of what you see.

2. Describe what the black and white semicircles are coming out of the speakers.  What do the dark bands represent and what do the white bands represent? Go to this site to figure it out.  Draw a picture of the dark and white bands and label what they are in your notes.

3. Click Audio Enabled (put your headphones on!).  Increase and decrease the frequency of the sound.  What changes happen to the wavelength of the waves coming out of the speaker and what happens to the pitch of the tone you hear as you do this?

Increased frequency does what to the wavelength?

Increased frequency does what to the pitch? (pitch is how high or low the note is)

4. Draw two pictures of sound in your notes, one with high frequency and one with low frequency.

4. Click “Listener” to hear what the man is hearing.  Move him closer and then further from the speaker.  Describe the changes in the sound the listener hears as distance from the source changes.

5. What does a change in amplitude do to the wave?    What is the meaning of the darker black and whiter white waves coming out when the amplitude is large?

6. Click the Measure tab.  Turn the amplitude all the way up, and the frequency to 100 hz.  Measure the wavelength of the sound wave.  Draw this in your notes and show the ruler in your notes with what you are measuring.

7. Increase frequency to 200 Hz and measure the wavelength, then 400, then 800.  What is the relationship between frequency and wavelength?

8. Pause the simulation, clear the wave, put the ruler so zero is right at the edge of the speaker, start the simulation timer, and then start the simulation.  Calculate the speed of sound by measuring how far a wave crest travels divided by how long it took to get there.  speed = distance/time

9. Go to the Two Source Interference Tab.  With two sources of sound that are identical, this is what happens.  Move the man slowly up and down.  What do you hear where the waves are clearly visible?  What do you hear where the waves are kinda gray?

10. Go to the Listen With Varying Air Pressure Tab and turn on Audio enabled.  Click Remove Air From Box and watch the pressure gauge as the air is removed.  What happens to the sound the listener can hear?

11. The air in the box turns dark when it is removed, what does this signify in the simulation (go back to question 2 for your answer, or, go back to question 2 to answer it better, it’s about pressure).

12. Add air to the box.  Write a statement in your notes about what sound waves travel through and what would you hear if you were standing on the surface of the moon with a loud radio right next to you.  Would you hear anything?  Why or why not?

Go to this website and answer the following questions.

1. List at least nine types of electromagnetic radiation.

2. Describe Radio Waves:  What do they come from? Are the wavelengths long or short?

3. Describe Microwaves:  What do they come from? Are the wavelengths long or short compared to visible light?

4. Describe Infrared waves: What can you see with them?  Is the wavelength longer or shorter than red light?

5. Visible Light: What makes it so important?  List the colors.

6. X-rays: What are they used for?  Is the wavelength shorter or longer than visible light?

7. Gamma-Rays: What things emit gamma-rays?  Is the wavelength shorter or longer than x-rays?

8. Are gamma-rays, x-rays, radio waves, and visible light the same thing?  What are they?

9. Describe what a photon is.

10. How fast does an electromagnetic photon travel?

11. Find the wavelength of the following:  Radio wave, Optical, X-ray.

12. Find the frequency of the following: Microwave, visible, gamma ray.

13. What types of electromagnetic radiation can reach the surface of the earth from space?

14. Go here and describe the electromagnetic waves that identified the black holes GRS 1915 and IGR J17091.

15. What causes the heartbeat-like changes in the x-rays that come from these black holes?

16. What is an event horizon?

17. What causes the jets that come out of GRS 1915?

Circuit and magnetic field quiz retake.

Today you are learning about the properties of waves.

Use the information on this website or google to create a comic about the following:

Square 1: Title: Wave Properties

Square 2: Transverse Wave.  What is it and find an image.

Square 3: Wave Crest.  What is it and find an image.

Square 4: Wave Trough. What is it?  Find an image.

Square 5: Wave Amplitude.  What is it?  Find an image.

Square 6: Wave Wavelength

Square 7: Longitudinal Waves.  What are they?  Find an image.

Square 8: Compression in a longitudinal wave.  What is it?  Find an image different from square 7.

Square 9: Rarefaction in a longitudinal wave.  What is it? Find an image that is different than square 7 and 8.

Answer the questions in Check Your Understanding in your notes.

6. Speed of Light

7. Speed of Sound

What you need to know:

Plasma is the forth state of matter and is made of charged or ionized particles.

Changing magnetic fields produce electric fields, thereby inducing currents in nearby conductors.

Do the following in your notes, Page 4

Plasmas

Go to this website about plasmas and answer the questions.

1. 99% of visible matter is in what form?

2. What are the states of matter usually found on earth?

3. What is considered the 4th state of matter?

4. list 9 things that are made of plasma (from the poster).

5. What is a plasma?

6. How do you create a plasma?

Magnetic Fields

Run this simulation to answer the following questions.

7. Click the tab called Pickup Coil and explain what happens to electrons in a coil when a magnet is moved through them.

8. If you increase the number of loops, what happens to the current?

9. Click the Electromagnet tab and explain what a current carrying coil does.

10. How does the number of coils effect the magnetic field?

11. Click the Generator tab, turn on the water, and turn on the field.  Explain how a generator works.

Things you need to learn today:

know how to determine the direction of a magnetic field produced by a current flowing in a straight wire or in a coil.

Magnetic materials and electric currents (moving electric charges) are sources of magnetic fields and are subject to forces arising from the magnetic fields of other sources.

Create a 9 square comic strip about magnetism and the right hand rule.  Include images that illustrate each idea.

Title Frame: Magnetism and the Right Hand Rule,  with an image of a magnetic field.  Also your name in a little box.

Square 2: The Earth has a magnetic field.

Square 3: A magnetic field can be seen by sprinkling iron filings on a magnet.

Square 4: A straight wire with a current flowing through it creates a magnetic field.

Square 5: A coiled wire creates a magnetic field.

Square 6: Many coils of wire create a strong magnetic field.

Square 7: The direction of a magnetic field is found using the Right Hand Rule.

Square 8: Point your thumb in the direction of the current and your fingers point in the direction of the field.

Square 9: Wrap your fingers around a coil in the direction the current is flowing and your thumb points in the direction of the magnetic field.

Return and go over quizzes.  Return notebooks.

Page 2

Magnetism Notes:

Three things you need to know:

1. Magnetism is caused by moving charges (currents).

Right Hand Rules:

2. A wire with current running through it will create a magnetic field around it in the direction your fingers curl on your right hand if your thumb is pointing in the direction of the current.

3. A coil of wire will create a strong magnetic field in the direction your thumb points when your fingers curl around the coil in the direction the current flows through the coil.

Electromagnetism kit.

Build Project #1 and answer the following questions

1. What does pressing the switch do to the current in the wire?

2. An electric current flowing in a wire has _______________________.

3. Looping a wire into a coil does what?

Do Project #2

4. Where is the magnetic field the strongest?

5. Which side of the compass points at the electromagnet?

6. Draw a picture of the iron filings on top of the electromagnet and on top of the magnet.

7. Arrange the paperclips like it says in step 2 and explain how a magnetic field is shaped.

8. Do step 4 and explain how the direction of the current effects the magnetic field.

9. Do step 5  and explain what an iron core does for an electromagnet.

10. Do step 6 and explain what happens.

Build Projects 3 and 4 and explain what happens in your notes.

Power = IV, where I is current in Amps and V is Voltage in Volts.  The unit of power is the Watt.

Example: A circuit with a 9 Volt battery and 2 Ohm lamp will have 4.5 Amps of current.  The power of the lamp is 4.5 Amps * 9 Volts, or 40.5 Watts.

Power Questions

When we buy electricity, we buy it in kilowatt-hours.  One kilowatt-hour  is 1000 Watts of power used for one hour.

Use the following calculator to calculate how much electrical power you cost.  Do your best to estimate what you use.

1. How much do you cost?

2. What do you do that costs the most?

3. Cut #2 in half, how much could you save?

1. Parallel Circuits notes

2. Parallel Circuits worksheet

3. Create a lemon battery.  See if you can boost the voltage by connecting them in series.  See if you can boost the amperage by connecting them in parallel.  See if you can light a lamp or feel a shock.