Author Archives: mrmurrayphysics

Projectile Motion using Angry Birds⤴

from @ i teach physics

Used Tracker motion analysis today to help us understand more about how projectile motion works. The video below shows how to use the autotracker function to analyse the motion of the Angry Bird.



We used the analysis to figure out how the horizontal and vertical motion of the bird changed over time. We also calculated the approximate length of Angry Bird required to give an acceleration similar to gravity. The question sheet below was used as a guide.

Projectile Motion Using Angry Birds


Projectiles⤴

from @ i teach physics

We started off with the simplest type of projectile - those that are projected horizontally. They therefore have an initial vertical velocity of zero so are pretty much the same as our calculations on bouncing balls and the like.



Things get a little more complicated when you launch projectiles into the air at an angle because the initial vertical velocity is no longer zero. If this is the case then you must think about the horizontal velocity and the vertical velocity separately.

5D – Vectors and vector diagrams⤴

from @ i teach physics



We draw vector diagrams to simulate what we see in the real world. I think some people still don't get this.

As I see it, there are two main rules when drawing vector diagrams:

1. Join your vectors 'tip to tail'
2. Use your common sense!

If the resulting velocity, displacement or force looks wrong then use your common sense. Th diagram is only showing you what will happen if you put these two velocities together or these two forces together.

5D – Errors and Uncertainties 2⤴

from @ i teach physics

When we have more than one uncertainty to deal with, we need to choose which one to take into account for our final answer. To do this, we use the value that has the greatest percentage uncertainty.

The percentage uncertainty is expressed as a percentage whereas the absolute uncertainty is written as a number.

5D – Errors and uncertainties⤴

from @ i teach physics

There are three types of uncertainty we need to consider for Higher Physics:

  • Reading; occurs when taking a measurement visually
  • Random; the subtle differences between experiments that produce differing results are caused by random errors
  • and Systematic; when there is something wrong with the equipment or the way in which it is used.
We can limit the effect of random errors by carrying out repeated measurments. You need to know how to calculate the mean and the error in the mean (approximate random uncertainty).

4H – Radiation types⤴

from @ i teach physics

Learning outcome: 
•We are learning what radiation is and its different types.
Success criteria: 
•Be able to describe the effects that radiation can have 
•Be able to give examples of sources of radiation
•Be able to give at least one method of detecting radiation
•Be able to describe the different types of radiation and how to protect ourselves against them

4H – X-rays⤴

from @ i teach physics

Learning outcome:  We are learning how x-rays work and how they can be used to diagnose health problems

Success Criteria: 
•Be able to describe one use for x-rays in medicine
•Be able to describe how x-rays can be detected
•Be able to describe how x-rays behave when they enter the human body
•Be able to describe the advantages of computerised tomography (CAT scan)
 

2.4 – Collecting volcanic ash⤴

from @ i teach physics

This week we set about collecting some of the volcanic ash from the recent Grimsvotn eruption. We collected this data as part of a British Geological Survey project to track the spread and concentration of the ash cloud.

We used sellotape and old catalogues atop a Land Rover in the car park; leaving these out for the entire school day on Tuesday. Thereafter, we attached the tape to the back of a sheet of paper which we will send to the British Geological survey for analysis.


Hopefully we'll have picked up some ash throughout the day. Pretty amazing when you think that it has travelled around 1000 miles to get to where we are.

How to make a webcam into an infrared camera⤴

from @ i teach physics

Every time I teach about infrared radiation, I have a lot of nice images I can show my classes and maybe even a clip or two from 'The Predator' to go with them. I saw an email today offering an infrared camera as part of your attendance on a course and it reminded me of the fact that I have always wanted one to show realtime images in the infrared spectrum.

Given that I've got a little more time on my hands than I normally do, on account of it being the exam season, I set about trying to make myself one.


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I opened up the nearest webcam and screwed off the plastic section surrounding the lens. On the back of it and found the infrared filter.









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I duly removed it and replaced the infrared filter and set about replacing it with a visible light one. I initially cut a small square from some blackened x-ray film and tested it but I was still seeing some colour. This guide  suggested that the best visible light filter could be scavenged from the negatives of some old colour film.


This was the trickiest part of the process but I eventually managed to fit two small pieces of this film in place on the back of the lens.


I've tested it briefly and it looks pretty good. I'll post some images later.

My camera was a basic Creative Live Cam but other manufacturers should be constructed in a similar fashion. A nice cheap alternative for bringing infrared into the classroom!

5CH – Past papers by topic⤴

from @ i teach physics

Now uploaded for the whole course. All of you should be working through these over the holiday, picking out the topics you find most difficult in the first instance. Any problems, give me a shout.