Archive for the ‘algebra’ Category
Pump Up the volume or Knock, Knock Knockin on Your skull wall!
February 18, 2013Well, little Mathpiggies, lots of students want to be Sound Engineers. It is time to tell cool middle school students that Sound Engineers NEED maths.
According to Salford Uni’s Guide to Decibels:
Just about every piece of audio equipment (microphones, loudspeakers, sound cards, amplifiers, mixers, etc) will have specifications expressed logarithmically (i.e. in dBs).
We don’t want to frighten junior sound engineers with complicated formulae. But we can have a little peak at SOUND ENGINEERING.
Here’s the deal.
You want to be a Sound Engineer like this:
……………………………………………………………….
Not like this:
Sound is tricky. It is a wave of compressed air travelling through the air to your ear.
It is measured in INTENSITY (Air Pressure per sq m) or Power (eg. Energy carried per sec in, say, Kilowatts).
…………………………………………………………………………..
If you have ever been to a Rock Concert you can feel the pressure of the sound wave of the BASS hitting your chest.
At an ELTON JOHN concert Mathspig could feel BENNIE AND THE JETS POUNDING ON HER CHEST …. COULD HARDLY BREATH.
The problem, however, is your ears can detect sound pressure over an astounding range of 1 to 1 trillion. Imagine a volume Dial if we used o to a trillion:
The other problem is your ears aren’t accurate. Your ears can detect doubling the intensity of a dripping tap but not doubling the sound of a jackhammer. This is why we can easily damage our hearing. We perceive the loudness as linear when it is not.
To measure sound volume engineers use Powers or Exponents:
Start with 1 million:
1000000 = 10 x 10 x 10 x 10 x 10 x 10 = 106
we call 6 the index and 10 the base.
Similarly 100000 = 105, 10000 = 104, 1000=103, 100=102, 10=101, 1=100; so why not express numbers from 0 to 1000000 as:
1,2,3,4,5,6.
We use decibels, which are 1/10 th of a Bell to measure sound.
But the sound intensity as measured in decibels dB is a ratio compared to the Threshold of Hearing (TOH), which is set at 100 = 1. Sometimes the sound intensity is a negative number because there are plenty of sounds below our hearing range. Just ask a dog or a bat.
This chart is from the excellent Physics Classroom
A noise that is 3B or 30 dB louder than another noise is hitting your ear drums with 103 or 1000 times more pressure. Ahhhhhhhhhhhh!
Here is a typical sound levels chart:
Here is the ear safety chart:
Turn Down the volume Exercise:
First, look at the chart above and compare dB readings. Note: Every 20 dB or 2 B increase in sound intensity increases the sound pressure on your ear drum by a factor of 100.
Now, we are going to convert the sound pressure in dB on the typical sound levels chart chart back from the dB (or log scale, mathpig teachers) to real scale by:
Convert to B by dividing each measurement by 10 and turning into a power and calculating value:
eg Ordinary Conversation: 60 dB = 6.0 B = 106 intensity = 1,000,000
Rock Band: 120 dB = 12.0B = 1012 intensity = 1,000,000,000,000
If you are interested in simple explanation of volume and Guitar Amplifiers go here:
or here
Deaf Metal
February 18, 2013Hellooo mathpiggies, I said HELLOOO MATHSPIGGIES.
Who has been to a rock concert recently? Studies show that adolescents often suffer temporary (sometimes permanent) hearing loss after going to a 3 hr rock concert in rows up to 18 away from the stage.
Rock Concerts Cause Temporary Hearing Loss in Teens
Specifically, 53.6 percent of the teens said they were not hearing as well as they did before the concert, and 25 percent reported tinnitus, which is ringing in the ears.
………………………………………………………………………………
Danger Zone Maths Exercise
For the Out door Rock Stadium (below) calculate the sound intensity (S) in dB for distance of 2, 10, 15, 20 and 100m (The last one is in the car park) if the sound intensity (S) is 120dB at 1m.
………………………………………………………………………………….
You’ll find everything you want to know at the Physics Classroom:
Oh It’s Hard to be Humble When You’re as Famous as Me!
May 4, 2012So you wanna be FAMOUS and fabulous and uber-cool too.
Maybe you wanna be the Chris Rock of maths. Being famous is soooooo cool.
…………….……You get attitude!!!
……………………You Get cool sunglasses!!!
….You get a chauffeur that’s not your mum!
But what are the chances? What is the probability that a kid at your school will become famous one day? Cate Blanchet went to Mathpigs kids’ school. But in Australia we don’t make a fuss. They haven’t put a picture of her on the wall or anything.
So mathspigs let’s work out the probability of you becoming a STAR, BABY!
Here is an interesting statistic from Psychology Today.
………………………………………………………………………………………….
The first question is how do you measure fame? Do you have to be on TV to be famous? Do you have to be a Hollywood star? Should you be a wax dummy in Madame Tussaud’s? Not as a job. I mean because you are so fabulously famous.
Perhaps, you could use Tom Weller’s humorous Rictus scale (a parody of the Richter Scale) for earthquake intensity using media coverage as a guide to fame. Just replace the persons name for the word ‘scene’.
I’m thinking around ’5′ looks like FAME, but you decide. Now count how many ex-students from your school (and any current ones) who have become famous in the last 20 years and do the maths.
…………………………………………………………………………………..
|
Rictus Scale # |
Richter Scale Equivalent |
Media Coverage |
| 1 | 0-3 | Small articles in local papers |
| 2 | 3-5 | Lead story on local news; mentioned on network news |
| 3 | 5-6.5 | Lead story on network news; photos in nation newspapers; governor visits scene |
| 4 | 6.5-7.5 | Network correspondents sent to scene; president/PM visits area; commemorative T-shirts appear |
| 5 | 7.5 up | Covers of weekly news magazines; network specials; “instant books” appear |
