Physics 30 - Dec 14

Today we finished up special relativity by finishing our example on mass increase that we started last Friday.  Students then had time to work on Assignment 4.3 and get ready for the in class assignment tomorrow on Unit 4.  Students should have done assignments 4.1-4.3 to prepare for the in class assignment.

Physical Science 20 - Dec 14

Welcome to the final week before the Christmas break everyone.  We have a full week ahead of us that will culminate with our unit exam on Thursday.  We are almost finished with refraction and today we looked at the optical systems of the eye, particularly the ability that our eye has to accomodate the fact that we are looking at objects at different distances and need to focus them on the retina of our eye.  We took a couple of slides of notes (slides 83-86) and then students got to sepnd the rest of the class working on their lab reports for Lab 3.2, which we did in class on Friday.  If students were absent Friday, there is a set of sample data in the physics folder of the course notes.  Use that sample data to complete the lab.  The report is due tomorrow. Tomorrow we will look at how we fix some common problems that happen with the optical system of the eye.

Physical Science 20 - Dec 8

Today we looked at how to find the image using the lens and magnification equations.  Students worked through a couple of examples and then they worked on Homework 3.5.  They will get more time to work on this tomorrow.  

Physics 30 - Dec 8

Today we talked about the twin paradox which is another neat ramification of time dilation.  Then we started to look at length contraction, another consequence behind special relativity and the constancy of the speed of light.  This means that for objects approaching light speeds, lengths of those objects actually decreases in the direction of motion as observed in another frame of reference.  We then looked at a couple of examples on how to calculate the length contraction.  This was all covered on slides 50-56 in the Unit 4 Notes.  Students were assigned Part 2 of Assignment 4.3.  We will go over this tomorrow.

Physics 30 - Dec 7

Today in class we started into a new topic - the theory of special relativity.  This is an advanced topic explained by Albert Einstein that has some really neat consequences.  One of those consequences is called time dilation, or the fact the when you move faster, time actually moves slower for you.  We went through what this means and how to actually calculate the time difference.  This was all covered on slides 23-46 in the Unit 4 Notes powerpoint. We did Example 8 and students were given time to do example 9.  Students were then told to begin working on Part 1 of Assignment 4.3 which is on time dilation.  Tomorrow we will start looking at another neat consequence - length contraction.

Physical Science 20 - Dec 7

Today in class students spent time drawing ray diagrams for lenses.  They followed instructions outlined on a handout called Finding the Image Graphically - Ray Diagrams for Lenses.  These instructions guided students through how to draw these diagrams.  It is similar to the diagrams we drew for curved mirrors and there are many analogies to it.  Students then spent the remainder of the class working on Assignment 3.2.  This will be handed in tomorrow.  Tomorrow we will then learn how to find the image mathematically.

Physical Science 20 - Dec 4

Today in class we went over the answers to Part C of the Refraction Practice Problems.  The answers are posted on the blog for students who were absent today.  Check the Answer Key folder in the Physics folder of the Course Notes link along the right of this webpage.  Afterwards, we started to look at an application of refraction called optics.  We learned about some terms that will be important in studying optics.  We then went on to cover lens diagrams and how to discover image characteristics graphically.  This was covered on slides 64-75.  We didn't quite finish off the diagrams today.  We will finish those off on Monday and work on Assignment 3.2.

Physics 30 - Dec 4

Today in class we then went on to learn about an extension to lab 4.2, the existence of something called dark matter.   We learned in the lab that more mass causes more speed for the centripetal motion.  This applies for simple motion that we see on Earth, like a stopper spinning around on a string, as well as the motion of stars in galaxies. 

We learned about a currently anomaly in physics.  This was the fact that stars in a galaxy are moving much faster than they should be.  The mass that consists within the galaxy that we can see is not enough to make the stars move so fast.  This is the basis for the search for dark matter. 

We watch a video today to explore these ideas a little further and to learn more about dark matter research.  Students answered a worksheet that went along with the video.  The worksheet is found here.  It is called Lab 4.2 Supplemental Worksheets.  The video is linked in 3 parts in the Course Video Youtube playlist.  It is called the Mystery of Dark Matter.  If you were absent today, please watch the video there.

Physical Science 20 - Dec 3

Today in class students just worked on Part C of the Refraction Practice Problems.  We will go over this tomorrow and then start to look at an application of refraction, the science of optics.

Physics 30 - Dec 3

Today in class we went over the analysis for Lab 4.2.  I have a handout of what we did today in the course notes link.  It is called Lab 4.2 Analysis Aid and it is found in the Unit 4 folder.  Tomorrow we are going to explore these ideas a little further and watch a video related to them.

Physical Science 20 - Dec 2

On Monday, the sub went over how to use Snell's Law and assigned Part B of the Refraction Practice Problems.  I reviewed this yesterday when I cam back and went through a couple more examples as well as looked at how to draw a refraction diagram.  I assigned Assignment 3.1 as well as Part B and we went over this stuff today with everyone.  Students handed in Assignment 3.1 and we went over the answers to Part B.

Today we moved on to look at critical angle and total internal reflection.  Critical angle is a special incident angle where the refracted angle will be 90 degrees.  If light tries to exit a substance at an angle greater than the critical angle, it wont be able to and it will just reflect around inside.  This is called total internal reflection.  They copied notes from slides 57-61 and worked on Part C of the Refraction Problems for the remainder of the class.  We didn't get to the assignment in Period 3 but we will tomorrow. For Period 2, Part C is due tomorrow.

Physics 30 - Dec 2

Hello everyone.  Sorry for my extended absence from posting but I was sick on the weekend and wasn't able to work on Monday.  We had a substitute teacher on Monday but we continued on with gravitational circular motion yesterday and looking at the motion of planets.  We derived a couple of equations and went through a couple of examples that utilized those equations.  These were examples 6 and 7 in your notes covered on slides 19-22. Assignment 4.2 was given at the end of the class.

Today we went through Assignment 4.2 and then did lab 4.2.  This lab was all about using circular motion to calculate the mass of an object.  Students collected data today and tomorrow we will look at how to analyze that data.  If you were absent today, there is some sample data in the Unit 4 folder.