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Only one week till exams. You know what you should be doing.

 

Images in mirrors and lenses

Again there are some resources on "You tube" for Ray diagrams.

 

Ray Diagram (Lens)

 

Images in plane mirrors

Tone Generator

Today in class we were playing with a tone generator program on a laptop. (I mean learning about sound waves)If you would like to down load the tone generator for yourself here is the link. Tone Generator Download site

Things to try
Play a single tone through some speakers and then walk slowly in front of the speakers listening for areas of constructive and destructive interference
Play two tones of slightly different frequency and create "Beats"
Drive your friends and family wild with disturbing noises
Have a good break and do some physics activities from your text books.

Practice Exams

It is a busy time coming up with the Senior Assessment fortnight starting on the 9th of September. You lucky year twelve physics students have several goals during this time.

 

Practice NCEA style assessments for the topics: 

• Mechanics
• Electricity and magnetism
• Atoms and radioactivity

Gain Credit in intenal assessments written examination

• Demonstrate understanding of Physics in an integrated context (3 Credits)

These will take place during the three hour exam on Thursday 11 September.

 

But wait there's more....

 

in another three hour session held in room B5 you will have the opportunity to gain further credit for:

• Take measurements of physical quantities and analyse data graphically to determine a relationship (4 credits)

The times for this assessment are  Thursday 11 September 8.45 and 11.35, Friday 12 September 8.45 and Monday 15 September at 8.45. Make sure you have booked into the session you can attend.

 

Beakman's Motor

On Friday we had fun making a working motor from some very simple items. Most of you managed to get yours to work. Don't forget to get all the activities done from chapter 17. Here is a picture of the motor we made and a link to a web page about the motor.

Beakman's Motor

Electro-magnetism

This week we have been refreshing our memories about magnetic fields around magnets and current carrying conductors. This diagram of the magnetic field associated with a Solenoid uses the "dart analogy" this time used to show direction of conventional current (positive to negative) in the wire.

 

I hope you've all done your homework or as our Brazilians might say "dever de casa". The homework of course was to finish activities 17a and 17b.

 

 

Electromagnetisim

Welcome back year 12 Physicists we are up to electromagnetism now.

Check out the link below for the real info about solenoids and their associated magnetic fields.

 

Magnetic field around a solenoid

Homework

Please complete today's hand out on circuit problems.

Homework

Activity 16 D. Please make sure you have done 16 A-C also. We need to move on to power in DC circuits next week.

Potential Divider

Potential dividers are also known as voltage dividers.The potential divider is a useful circuit for providing a voltage to a component that requires a smaller voltage than the supply voltage in a circuit.

Follow these links for some webpages about potential dividers.

 

Potential divider 1

 

Potential divider calculator

 

Potential divider 2

Resistance

Homework re-read chapter 16 upto to activity 16A and then complete the activity. Check out this webpage about resistance:
http://hyperphysics.phy-astr.gsu.edu/Hbase/electric/resis.html#c1

New Topic Electricity

At last the Mechanics topic is over. This is the biggest topic in terms of content and although the topic test is behind us please don't forget what we have learnt. It is important to review some of the mechanics section every week as the year goes on so that when the final exams come up it is not just a distant memory.

Our next topic is electricity and we start with the idea of the electric field. The following two links are a good place to follow up what we talked about in class this morning.
http://www.colorado.edu/physics/2000/waves_particles/wavpart3.html
http://hyperphysics.phy-astr.gsu.edu/Hbase/hframe.html

Explain that concept

We are getting close to the common test. One last thing to prepare for is the explain questions that are definitely going to be part of the test.

The following link is to a document of explain questions.



Explain Questions

Re-arranging equations

What would it be like If you had your own pet teacher ?

• who could show you how to re-arrange equations and
• do it over and over again until you got it
• and the teacher would never get tired
• never get bossy
• never tell you off for not paying attention

Well get real folks, teachers like that do not exist, but youtube videos do. 

The following links lead to a couple of simple demos on re-arranging equations. By the look of things there are heaps more if these don't do it for you.

1. Re- arranging equations using Physics examples   
2. Re-arranging equations maths examples

 

here are some static pages if your internet connection is slower

 

1. Algebra instructions from Massey University
2. A pdf file on re-arranging equations

 

 

 

 

Energy and combined mechanics

We've spent the last couple of spells carrying out some "serious" research into:

• spring constant
• elastic potential energy
• energy transfer
• projectile motion

It has been a real life combined mechanics problem using rubber bands, retard stands, force meters and folded up pieces of paper. Luckily no lasting injuries were sustained but it became apparent that some work needs to be done on re-arranging equations.

 

The homework sheet for the weekend on "Kinematics, Momentum and Energy" should give you some more practice.

 

Happy Physics   

Tutorial

Monday lunchtime in room B5. If you have any questions about what we've been doing in class or need to figure out what it was I was trying to explain to the class come along to B5 on Monday.

Energy

This weekend  your homework is to finish the all activities from the handout you recieved on Thursday. Energy is in part, a revision topic from the year Eleven science course. So make sure you are confident with all these problems.

Moving in Circles

Your homework is to complete the activity 12A on page 143 of our Physics text book.

 

Next spell we begin our final topic "Energy".

Moving in Circle

I was impressed to see how enthusiastically the class took on Friday's challenge to determine the mass of a retort stand using a known mass and the principles of equilibrium. Well done class!

This week our topic is circular motion. For me this topic starts to explain why we began the year going on so much about the quantity velocity having two components, magnitude and direction. All the circular motion problems we will consider involve the magnitude of the velocity remaining constant but as the objects are moving in a circle the direction of the movement is continually changing.

This means the velocity is constantly changing and as acceleration is the rate of change of velocity the object will be accelerating.

Homework assignment

You should have picked up your NCEA style question on momentum at the end of our class today.

Please complete this for our lesson on Thursday. Help me out here class I need some positive stuff to feedback to your parents next Tuesday!

Keep Working

We're on the home straight now. Projectile motion is finished you just need to complete the activities 11A and B.

Don't forget parent teacher interviews are on next Tuesday evening.

Holiday Physics

You may be asking yourself "what should I be doing during the holidays to improve my understanding of Physics"?

 

The answer is:

• make sure you have completed all the activities in the text book for the sections of work we have covered
• look at the specifications for the achievement standards we have covered content for:
• AS90252     2.1 
• AS90255     2.4 
• AS90258     2.7 
• do any of the specifications make sense in relation to what we have studied in class?
• the specifications were given to you in the hand out from the start of the year

Projectile motion

We are coming to the end of the mechanics section of the course. We've only got circular motion and energy to go. Don't forget our "rules" describing projectile motion as they are the key to understanding and solving P. M. problems.

Check out the links below:

Projectile motion and vectors
Projectile Motion Simulations
Projectile motion FAQs
NZ High School Physics Resources


Cheers
Mr Edwards

Vectors Vectors Vectors

Now You have completed (?) the simple vector work sheet why not check out some more in depth vector concepts.

 

Regards

Mr Edwards

Vectors

Walking around the room it is apparant that some basic work with vectors is needed. Vector Worksheet? Are your Vector skills up to the mark?

 

Regards

Mr Edwards

Homework

Please continue with the activities 10 A and 10 B.

 

By now you should be geting a good idea about the style of problems you will face on the Momentum topic.

 

Cheers

Mr Edwards

Homework for Monday

Text book activity on Momentum and Impulse activity 10A on page 123.

 

Please complete at least two more problems. Of course the stars will do more.

 

Regards

Mr Edwards

Survey

I've been playing with a little survey tool called Survey Monkey.
Please complete the survey by clicking the link on the right. You may even be inspired to make one for yourself.

Regards
Mistery

What to do in the weekend?

If you did not finish and hand in the write up for the Rolling Trolley practical, please have it ready for our lesson on Monday.

 

Mr Edwards  

Rolling Trolley Practical

Today's class activity involved all about our favourite physics skills of :

• observing motion
• measuring time
• collecting data
• minimising measurement errors
• graphing data
• transforming data
• graphing transformed data
• determining an equation for a relationship

Today was the data collection Friday we process and present the results.

Happy Fizx

Homework

Please finish the forces worksheet.

Looking back at where we've been

Since February we have been looking at the Mechanics topic. This has also provided a useful context to covering some of the maths and experimental skills required at this level.

There are a wide range of useful physics resourses online and those that demonstrate concepts through the use of applets are particularly good. This concept map for mechanics topics is from a good basic website that covers many of our topics this year.

Happy Fizziks
Mr Edwards

Momentum and Impulse

The words of the week are Momentum and Impulse. They are quite closely related and the Momentum concept is going to make use of all those vector maths skills we have been honing over the last few weeks.


A good way to think about momentum is as an objects "quantity of motion". It combines the motion and the mass of a object. Impulse is the net force applied to an object multiplied by the length of time it is applied.

The effect of impulse on an object is to accelerate (or retard) it which of course will change it's momentum. In fact: Impulse = the change in Momentum.

Happy fizziks
Mr Ed

Physics = Applied Mathematics

There is now one less excuse for being behind in your homework or not being totally prepared to do well in year twelve physics this year. By checking this blog you be able to figure out where we are up to in our physics marathon.

Please feel welcome to ask any questions via comments it is very likely that you have having trouble with some aspect of the course other students will be too.