Wednesday January 30th

Today we talked more about waves! There are 5 characteristics of periodic waves they are:
Frequency

Period
Amplitude
Phase
Wavelength
Speed
Wave Front

Frequency

Frequency is the number of vibrations per unit of time. The SI Unit of time is hertz (Hz) and symbol for frequency is “f.” 1 Hz= 1 s^-1. This picture shows different frequency waves.

Period

Period is the time required for one complete vibration. The symbol for Period is “T” the SI Unit is second and it is the reciprocal of frequency T=1/f

This shows one period of a graph.

Amplitude

Amplitude is the maximum Displacement of a particle of the medium from its rest position. Another name for amplitude is height (of the wave).
Examples:

• Light wave amplitude


• Brightness


• Sound wave


• Amplitude


• Loudness
  
  
  

Phase
Waves that cross paths while traveling in the same direction are considered to be in phase
Phases have
o The same displacement from the rest position
o The same direction of motion

Here wave 1 and wave 2 are said to have a phase difference of 2(pi), or simply are in phase, because both waves have the same wavelength and rise and fall together. Any two waves with a phase difference of a multiple of 2(pi) are in phase.

Wavelength

• The wavelength of a wave is the distance between any two adjacent corresponding locations on the wave


• The distance is usually measured in one of three waves


• Trough to trough


• From the start of a wave cycle to the next starting point


• Crest to next crest


• Shown below:
  
  
  

Speed of a Wave

• The speed of a wave equals the product of wavelength and frequency


• Examples


• We see the bat hit the ball before the crack is heard


• Shouting and hearing your echo

Wave Front

• A wavefront is a line or surface, in the path of a wave motion

We also had a worksheet for homework. It's called waves #1!

Tuesday, January 29

On Tuesday, we began our unit on waves. Waves can be defined as "a vibratory disturbance" that goes through an object or space. These can include water, sound, and light waves. Waves can also be mechanical or non-mechanical. Mechanical waves require a material to pass through and vibrate the particals of the object. The most basic of these are sound and water waves. Non-mechanical waves on the other hand, do not need to travel through an object. They are able to go through empty space. Some of these waves are visible light, infrared light, or radio and tv waves. We also briefly went over the difference between pulse and periodic waves. Pulse is one wave while periodic waves are a series of waves that are the same size. Periodic waves also have a constant time in between each peak. Finally, we discussed the two different kinds of waves which are longitudinal and transverse waves. Longitudinal is when the movement is parallel to the direction of travel of the wave and transverse is when the movement is perpendicular to the direction of travel of the wave.

Midterm Feedback

Before the midterm, I definitely did some of the packets and tried to make sure that I understood most of the information. I have an A+ in the class, and it just seemed impossible that I could do bad on the midterm. My grade on the midterm was definitely not what I expected...during the test, I really thought I understood the material, and I am a little confused on how my grade turned out to be so low.
The curve helped me a lot, but it kinda scares me how I have better grades in my AP classes than I do in my regents physics class. Just an observation...
Hopefully the regents is better!

MIDTERM

I thought the midterm was definitly challenging. After I left I didn't feel all that positive about my score. I think I could have tried a little harder to study but I think those review packets really helped.

Midterm

I really liked the review packets we got for the midterm...all of the info on the midterm covered them. EXCEPT. I looked at the answers for the questions in the packets, and they often didnt match with the questions I came up with. And I had no idea how to get those answers. So. I know that it is more work to put how to get the answers in the packets, but I know it would have helped me so much. I wasnt happy with my grade at all, it was my lowest grade on any midterm I've ever gotten. But for the final, we will hopefully be better prepared because we wont be getting any new teachers and we will all be more used to physics class.

Midterm comment

i agree with kassidy. the multiple choice was the hard part and didnt make much sense because alot of the problems we were probably taught the formula but only once and was never really told to us that it was important to know and there werent much practice problems on them.

MIdterm

it was alright. the packets didn't match the actual test which doesn't help. grades probably would have been worse if it was a local test. earlier prep for final would probably be a good idea.

Midterm

I thought that the midterm was really surprising because when i was taking it i thought it was kind of easy, but when i got it back i realized that the questions are tricky. They set you up to think you might have the right answer when in reality, you might not have done the problem correctly. I went in and looked over my test and redid all of the questions i got wrong. I feel that that helped me a lot and now i know what to look for in similar questions. Also i am going to spend more time studying for the final when it comes time.

Midterm Feedback

I thought the midterm multiple choice was very difficult. The written part was easier and i was able to write the equation, solve it, and came up with the answer. I was confused on the multiple choice because a few of the questions, i had no idea which formula i was supposed to use. I tried many formulas and for some of the questions i was successful at coming up with the correct answers, others i couldn't resolve it. Overall i walked out of the physics midterm kinda brain dead due to three hours of bio before physics. I could have done A LOT better on this midterm if i wasn't so caught up in studying for Bio. But for the finals, i would like a few class periods of Mr. writh going over and briefly touching on subjects we learned earlier in the year. It was hard for me to remember to do some of the stuff earlier in the year because we never reviewed it but it was my fault i didn't review those chapters before the midterm. So for the finals i will study a lot harder, and go on for extra help on earlier subjects we learned.

Monday January 28 2008

We started the day getting our Midterm grades back.....which were not fantastic. Mr. Wirth is checking to see if he is allowed to actually hand those exams back to us. He handed back an old test and quiz. Mr. Wirth told people that had labs that need to be handed in, second quarter is over! We then discussed alittle bit about Mr. Wirth's expectations. Even though this is second semester we still need to have a good work ethic. We need to be respectful of others around us and limit the talking in class. We need to have a quiet learning atmosphere, as he has previously stated.
We then found out our next unit would be: waves. We watched about a 10 minute video on waves. It spoke about all different types of waves. From ocean waves to waves of people. It touched on amplitude and frequency which I am sure we will be covering in the next couple of days. It was an interesting introduction video.
This is the beginning of second semester we are starting with a "clean slate."
There was not much material learned today just mostly tieing up some things.

I thought the Midterm was a little difficult but not terrible. I feel like if we had a hard copy like Sarah originally said it may have been beneficial. I think we were pretty well prepared it was just a matter of working through those equations and deciding what information is necessary etc. I feel as though I could have done better though.

Midterm

The midterm wasn't that bad. I was a little nervous seeing as how we've had three different teachers this year, but I was comfortable with all the material covered. I would like to look over my test and see what I got wrong though. No particular unit was too difficult, but I probably could have reviewed Work, Power, and Energy a little more. It was a fair test and we were very well prepared.

I think that we were pretty well prepared for the midterm. I think that most of the questions were fine but a few of them I had no clue what they were asking/what answer I was looking for. I agree with Sarah about getting a chance to look at a hard copy of the midterm so we could see what we got wrong and learn from it. I thought that I did better of the midterm than I actually did. But I guess I need to space my studying out and start earlier.

I didn't think the midterm was hard at all. I thought it was pretty basic and got stuck on about four questions. That's why I'm surprised at the grade I got. It isn't a bad grade at all but it's worse than I thought I did. As for studying, I did but not a lot because I felt confident in most of the material and still felt that way after the test. The one thing that might have helped would have been getting our Work and Power Quiz back before the test to see if we were doing the problems right. Otherwise, I didn't think the test was hard so I'm confused about my grade and what happened. I think we should get to look through the actual copies of the tests in class and just return it at the end of the period. That way, we have the chances to ask questions if we want and we can see where we are going wrong because this material will be on the final.