Intro Physics conducted a lab investigation on sound waves, looking at properties of sound for tuning forks, the human voice, an automated tone dialer and musical instruments. We contrasted pure tones, with tones accompanied by overtones. A tuning fork struck softly vibrates with a sole, fundamental frequency, but one that is struck sharply produces overtones simultaneously with the fundamental tone. The human voice produces a variable number of overtones with the fundamental frequency and that gives each voice its characteristic sound. The same is true for musical instruments. Two instruments playing the same note do not sound the same due to the numbers and intensities of overtones produced by each instrument. For the tone dialer, it was seen that the phone company assigns each number a row and column frequency to indicate its position on the matrix. We will talk about this lab on Monday and then spend more time with sound intensity.
Physics D, F and Honors Physics started work on wave interference and diffraction today. We discussed the conditions required to observe interference of light and how those conditions could be and were met to demonstrate light interference as part of the evidence package that light was actually a wave. Folks saw laser light interference and the dark/light fringes characteristic of light interference and we then looked at how to calculate the position of those fringes. On Monday, we'll add diffraction to the discussion, which helps to explain how Young's double-slit experiment was able to document light interference.
3/28/14
3/27/14
A Day of Tests
Physics D, F and Honors Physics took their Refraction exam today and move onto Diffraction and Interference tomorrow. Intro Physics went over their Waves exam and then moved onto an exploration of sound. We reviewed the basic nature of sound waves as longitudinal, mechanical waves, factors that affected the speed of mechanical waves and then turned attention to loudness. We linked loudness with the amplitude of a sound wave and then approached the idea from the perspective of intensity, both absolute and relative. We looked at the intensity formula, which we'll practice with tomorrow, and then began to discuss the logarithmic nature of the ear's perception of sound and how that was incorporated into the decibel scale. Tomorrow, we finish with loudness, look at the range of hearing/vocalization of sounds of humans and other organisms and get a little math practice with intensity.
3/26/14
Exams and Their Preparation
Intro Physics took their Waves test today and will move on to the specifics of sound and light tomorrow. Physics F and Honors Physics went over their lab work on lenses and image formation before moving into reviewing for their exam tomorrow. Physics D conducted their lab work, with their review having been completed yesterday. After tomorrow's round of exams, the upper-division physics folks move onto a quick look into diffraction and interference before turning towards electricity.
3/25/14
Simulation
Here's a little simulation for image formation by a converging lens. Check the 'virtual image' box to have the program include those as options and 'principal rays' to show the types of rays you used to construct ray diagrams.
Starting Some Review
Physics D and Intro Physics took the period to go over last night's homework and review for their upcoming exams (Thursday for Physics D and tomorrow for Intro Physics). Physics F and Honors Physics will have their review tomorrow and took today to complete their lenses labs. Make sure you are aware of patterns of image formation by convergent and divergent lenses, the definition of depth of field and how depth of field, aperture and shutter speed relate in the field of photography. Physics D will work on these labs tomorrow, probably only the convergent/divergent lens lab and all upper division physics folks take their refraction exam on Thursday.
3/24/14
Lenses
Physics D did not meet due to an assembly, so will only conduct one investigation of their lab unit before Thursday's test. Physics F and Honors Physics started their labs today, beginning with lenses and image formation and moving on to aperture and depth of field. Depending on the time allotted groups made it to different stopping points and will continue with their work tomorrow. Most groups, at minimum, worked through real image formation by double-convex lenses and saw clearly the pattern demonstrated in the table in their textbooks that we referenced during lecture, but by tomorrow at the end of the period, all groups should be finished with both experiments and ready for Wednesday's review in preparation for Thursday's exam.
Intro Physics took on the topic of standing waves today, and used their lab on this topic to highlight their work. We discussed the physical structure of standing waves,the interaction of reflection and interference that forms them and relationship between frequency and wavelength for standing waves and saw how it met the pattern for other wave types, as wavelength decreased through the standing wave series, the frequency increased to keep the speed of the waves constant in the medium. We looked at how to calculate wavelength for standing waves and use wavelength, along with the wave speed formula to assess the frequency of the standing waves. We then noted that the relationship between the frequency of standing waves in a series and saw they were integral multiples of each other. In the next chapter, we'll examine standing waves in more detail when we discuss music and harmonic series. Tomorrow, we review tonight's homework, the chapter concepts and answer questions in preparation for Wednesday's exam.
Intro Physics took on the topic of standing waves today, and used their lab on this topic to highlight their work. We discussed the physical structure of standing waves,the interaction of reflection and interference that forms them and relationship between frequency and wavelength for standing waves and saw how it met the pattern for other wave types, as wavelength decreased through the standing wave series, the frequency increased to keep the speed of the waves constant in the medium. We looked at how to calculate wavelength for standing waves and use wavelength, along with the wave speed formula to assess the frequency of the standing waves. We then noted that the relationship between the frequency of standing waves in a series and saw they were integral multiples of each other. In the next chapter, we'll examine standing waves in more detail when we discuss music and harmonic series. Tomorrow, we review tonight's homework, the chapter concepts and answer questions in preparation for Wednesday's exam.
3/21/14
Light and Waves
Intro Physics continued their discussion of wave interactions with a discussion of refraction and interference. We discussed when refraction would occur, described how the path of travel change when a wave enters a particular material and then moved to both constructive and destructive wave interference, along with the formation beats. On Monday, we'll discuss standing waves, Tuesday is review day and Wednesday is exam day. On Thursday, we begin a specific examination of sound.
Physics D, F and Honors Physics reviewed their work with lenses, then turned attention to optical phenomena such as total internal reflection, mirage formation and dispersion. We looked at examples of natural and man-made fiber optics, then examined how mirages are formed due to atmospheric refraction and dispersion, along with it's relationship to rainbow formation. On Monday, Physics D will review for their upcoming exam (Thursday), while F and Honors Physics begin work on two lab activities for image formation by lenses and the relationship between aperture and depth of field. D Block will start on these labs Tuesday.
Physics D, F and Honors Physics reviewed their work with lenses, then turned attention to optical phenomena such as total internal reflection, mirage formation and dispersion. We looked at examples of natural and man-made fiber optics, then examined how mirages are formed due to atmospheric refraction and dispersion, along with it's relationship to rainbow formation. On Monday, Physics D will review for their upcoming exam (Thursday), while F and Honors Physics begin work on two lab activities for image formation by lenses and the relationship between aperture and depth of field. D Block will start on these labs Tuesday.
3/20/14
Lenses!
Physics D, F and Honors Physics worked with the mathematics of thin lenses today. We reviewed the relevant formulas, which we had used in the last chapter for mirrors, and the sign conventions for lenses before folks were turned loose to work problems, draw ray diagrams and answer their questions independently. Tomorrow, we move onto refractive phenomena such as mirages, total internal reflection and dispersion.
Intro Physics reviewed their labs of wave properties, then took a moment to review reflection before moving on to diffraction, the ability of waves to spread around the edges of an object or through an opening in the object, like a door. We discussed examples of diffraction and touched on refraction before the bell. Tomorrow, we take on refraction and interference.
Intro Physics reviewed their labs of wave properties, then took a moment to review reflection before moving on to diffraction, the ability of waves to spread around the edges of an object or through an opening in the object, like a door. We discussed examples of diffraction and touched on refraction before the bell. Tomorrow, we take on refraction and interference.
3/19/14
Waves and More Waves
Physics D, F and Honors Physics continued on with light and refraction today by looking at lenses. We completed light and reflection last week and, after Monday's exam we turned towards refraction, the change of path of light due to traveling a different speed in a new medium. Yesterday, we defined refraction, discussed when refraction did and did not occur, defined the index of refraction and discussed how the values could be used to assess properties of a substance in terms of the behavior of light and used Snell's Law to evaluate the exact path of travel of light in a material. Today, we took on lenses and began to discuss properties of lenses, contrast diverging and converging lenses and take a look at ray diagrams for lenses. Tomorrow, we'll continue on this with this and get some practice with the math involving lenses.
Intro Physics continues with waves and wave behaviors and, today and yesterday, worked on lab work concerning wave features, wave reflection and interference. We used springs to model transverse and longitudinal waves, set up standing waves in a rope and used a microphone and the Vernier system to examine sound waves and the phenomenon of beats. Tomorrow, we'll discuss these labs and continue beyond reflection to other wave behaviors, such as refraction and diffraction.
Intro Physics continues with waves and wave behaviors and, today and yesterday, worked on lab work concerning wave features, wave reflection and interference. We used springs to model transverse and longitudinal waves, set up standing waves in a rope and used a microphone and the Vernier system to examine sound waves and the phenomenon of beats. Tomorrow, we'll discuss these labs and continue beyond reflection to other wave behaviors, such as refraction and diffraction.
3/10/14
Waves and Optics
Intro Physics worked on a lab targeting energy conservation in simple harmonic motion. We let a spring oscillate, after experimentally determining the spring constant, and saw the pattern conform nicely to a sine curve. Looking at the graphs of kinetic energy and elastic potential energy, it was seen that they were inverse of each other and, at any point, the sum of the two energies was about the same value as any other point in the motion. We then added a large coffee filter to the bottom of the spring's mass and saw how mechanical energy was no longer conserved in the presence of significant frictional resistance. Tomorrow, we'll dig further into waves and wave features.
Honors Physics, Physics D and Physics F worked on practice problems for curved mirrors. Folks had to use the mirror formula as well as the two versions of the magnification formulas to solve problems involving image properties, object properties or mirror properties. Most people realized that reading the problem carefully and using the information to correctly assign signs for values was a critical skill for success. Physics D and F also had to draw ray diagrams for concave mirrors, while Honors Physics had to the same for both types of mirrors. We'll go over these problems tomorrow before moving on to color and polarization.
Honors Physics, Physics D and Physics F worked on practice problems for curved mirrors. Folks had to use the mirror formula as well as the two versions of the magnification formulas to solve problems involving image properties, object properties or mirror properties. Most people realized that reading the problem carefully and using the information to correctly assign signs for values was a critical skill for success. Physics D and F also had to draw ray diagrams for concave mirrors, while Honors Physics had to the same for both types of mirrors. We'll go over these problems tomorrow before moving on to color and polarization.
3/7/14
Riding the Waves
Intro Physics moved into the area of vibrations and waves today, with an overview of the nature of waves, the difference between mechanical and electromagnetic waves and how waves relate to vibrations. We dipped our toes into a specific type of vibration, that which is described by simple harmonic motion and Monday's lab will allow folks to examine a system exhibiting simple harmonic motion (an oscillating spring), measure the spring force (which is the restoring force of the system) and how energy is conserved in the motion.
Physics D completed their lab work with curved mirrors and will discuss that lab on Monday. Honors Physics discussed their lab today and continued to discuss properties of image formation by curved mirrors. Physics F did the same and had time to work a couple of practice problems for mirrors. On Monday, time will be given for people to practice using the mirror equation and magnification equations for both concave and convex mirrors, as well as draw ray diagrams. The test that is currently scheduled for Wednesday will likely get moved to Thursday, but we'll decide for certain on Monday.
Physics D completed their lab work with curved mirrors and will discuss that lab on Monday. Honors Physics discussed their lab today and continued to discuss properties of image formation by curved mirrors. Physics F did the same and had time to work a couple of practice problems for mirrors. On Monday, time will be given for people to practice using the mirror equation and magnification equations for both concave and convex mirrors, as well as draw ray diagrams. The test that is currently scheduled for Wednesday will likely get moved to Thursday, but we'll decide for certain on Monday.
3/6/14
Mirrors and Reflection
Intro Physics took their heat, temperature and phase change exam today and move on tomorrow to vibrations and waves.
Honors Physics, tiny class that it was, completed their curved mirrors lab and Physics D started the same lab during the long block. Both concave and convex mirrors were examined and patterns of image formation by these mirrors were investigated. Concave can make both real and virtual images and we looked at how the position of the object with respect to the mirror affected the properties of the real image that was formed. Convex can only make virtual images and we used the parallax method to determine image location. Tomorrow, D Block will complete the lab and Honors Physics will discuss the lab as part of the discussion about mirrors and the mirror equation.
Physics F discussed their mirrors lab and looked at how the data collected in lab related to the mirror equation we are using in class. We then took time to begin discussing the properties of concave mirrors and how those mirrors made images. We'll continue with this tomorrow and add on convex lenses, along with the use of ray diagrams to determine image position and properties.
Honors Physics, tiny class that it was, completed their curved mirrors lab and Physics D started the same lab during the long block. Both concave and convex mirrors were examined and patterns of image formation by these mirrors were investigated. Concave can make both real and virtual images and we looked at how the position of the object with respect to the mirror affected the properties of the real image that was formed. Convex can only make virtual images and we used the parallax method to determine image location. Tomorrow, D Block will complete the lab and Honors Physics will discuss the lab as part of the discussion about mirrors and the mirror equation.
Physics F discussed their mirrors lab and looked at how the data collected in lab related to the mirror equation we are using in class. We then took time to begin discussing the properties of concave mirrors and how those mirrors made images. We'll continue with this tomorrow and add on convex lenses, along with the use of ray diagrams to determine image position and properties.
3/4/14
Energy, Be it Heat or Light
Intro Physics worked with latent heat and phase change today in class. We discussed phase changes and phase-change diagrams, then looked at how to calculate the amount of energy required to change the phase of a substance - latent heat. We discussed why latent heat of vaporization was greater than latent heat of fusion and worked through an example where folks had to calculate the energy required to heat a substance, change its phase, then continue to heat it to a final temperature. We'll go over the homework problems in class tomorrow before beginning to review for Thursday's exam.
Physics D and Honors Physics began to work on the area of spherical mirrors today in class. We looked at the the types of curved mirrors (concave and convex), the nature of radius of curvature and focal length and started to examine how these types of mirrors formed images. We'll continue with this tomorrow for D Block and Honors Physics will work on a lab that will focus on image formation and the formula we introduced today in class. Physics F conducted this lab today, looking at images formed both by concave and convex mirrors. Concave mirrors form both real and virtual images, depending on placement of the object, but convex mirrors only form virtual images. We'll start discussing the details of image formation tomorrow in class, and review our lab as part of the class discussion.
Physics D and Honors Physics began to work on the area of spherical mirrors today in class. We looked at the the types of curved mirrors (concave and convex), the nature of radius of curvature and focal length and started to examine how these types of mirrors formed images. We'll continue with this tomorrow for D Block and Honors Physics will work on a lab that will focus on image formation and the formula we introduced today in class. Physics F conducted this lab today, looking at images formed both by concave and convex mirrors. Concave mirrors form both real and virtual images, depending on placement of the object, but convex mirrors only form virtual images. We'll start discussing the details of image formation tomorrow in class, and review our lab as part of the class discussion.
2/28/14
Moving On To Light
Physics D, F and Honors Physics began their discussion of light today with an overview of the nature of light as a transverse, electromagnetic wave (when it behaves as a wave), the members of the EM spectrum and their uses, the speed of light and how Huygens viewed light waves and their propagation. Physics D and Honors Physics also looked at light intensity, but Physics F will get there on Monday, when they will also start, with the other sections, on an examination of reflection and reflection by flat mirrors.
Intro Physics discussed yesterday's lab investigation on phases and phase change before turning attention towards the liquid and gas phases of matter. We continued to describe matter in terms of energy, particle motion, volume and shape and saw how the pattern of increasing energy took solids to liquids and then gases. We'll hit plasma on Monday and then begin our look at phase changes, phase change diagrams and latent heat.
Intro Physics discussed yesterday's lab investigation on phases and phase change before turning attention towards the liquid and gas phases of matter. We continued to describe matter in terms of energy, particle motion, volume and shape and saw how the pattern of increasing energy took solids to liquids and then gases. We'll hit plasma on Monday and then begin our look at phase changes, phase change diagrams and latent heat.
2/27/14
Saying Farewell to Sound
Physics D, F and Honors Physics took their Sound exams today and begin with light and reflection tomorrow. Intro Physics conducted a lab investigation on phase changes. We began talking about phases of matter yesterday and today, examined water undergoing the liquid-solid phase changes. We charted the temperature change of freezing water and melting ice and overlaid the graphs to see that the solid-liquid change (melting) occurred at the same temperate as the liquid-solid transformation (freezing) and that the temperature did not change during the process of changing phase. We'll discuss the lab in class tomorrow as we continue looking at phases of matter and latent heat.
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