Simple Pendulum Experiment (1 Viewer)

[currysauce]

Hello all, i have a prac test on this dot point and was woundering if there is anything i should know?....

i.e the independant and dependent variable... control.... etc.....

also could someone re-arrange this eqn for me....

i did it and was hoping someone gets the same result

T = 2pi √ l / g

to make l and g the subject!!... thanks people.

 

[SarahMary]

l=gT^2/4pi^2
g=4lpi^2/T^2

 

[currysauce]

thankyou....

any thoughts on the independent and dependent varibles, got me a little stumped?

independent ? gravity?....

 

[Helstar87]

thankyou....

any thoughts on the independent and dependent varibles, got me a little stumped?

independent ? gravity?....

So your using that equation to work out the accelearation due to gravity using a pendulum right? Well that's what we used that equation for...
The Independent variable in the pendulum expt. is the length of the string of the pendulum
The dependent is the period
Sorry I don't know if that will help much... Is that what u were after?

 

[currysauce]

i meant the whole experiment probably

 

[TimeAndTide]

I got 9.5/10 for this prac. I'll scan it when i get my book back.

 

[powerhouse]

That would be great thanks.

Email it to me customxp@hotmail.com or MSN.

 

[currysauce]

send to me too!... currysauce@hotmail.com

 

[veridis]

just chuck it up here ey

 

[TimeAndTide]

added both of you...msn

 

[menty]

could i have it too. i missed out on this prac, so i got nfi wht to do

MSN: kevin@loadedreality.com

 

[Helstar87]

Pendulum Experiment

Aim:- To find out the value for acceleration due to gravity using computer-assisted technology
Hypothesis:- If I use a pendulum motion and measure the period whilst varying the distance, then the acceleration, when calculated will be 9.8m/s/s
Variables:- Independent:- Length
Dependent:- Period
Controlled:- mass, angle
Method:- 1) Obtain equipment and set up apparatus. (sorry. I don't have an scanner, hope you can follow this)
2) Attach a 100g pendulum to a 1m rope.
3) Pull the pendulum out so that it it 10 degrees out from its original position and let the pendulum go
4) Time how long it takes for the pendulum to complete 10 periods (one period = the time it takes to get back to its starting position
5) Divide this time by 10 to get the time taken to complete one period.
6) Repeat steps 3-5 using the 1m rope for the pendulum 4 more times then take the average time.
7) Repeat steps 3-6 using a 20cm, 30cm, 40cm, 50cm, 60cm, 70cm, 80cm and 90cm rope for the pendulum.
Results:- The formula is g = 4 x pie x length (of the pendulum)
--------------------
T squared
If you then draw up a graph where the 4 x pie x length values are on the vertical axis and the T (period) squared values are on the horizontal axis, the slope = the acceleration due to gravity.
There are then experimental reasons for variations from 9.8m/s/s
The biggest being random error - timing
Absolute error - Protractor and metre ruler
Paralex error - Protractor, metre rule
Systematic - Didn't measure to the pendulums centre of mass.
Non-experimental reasons for variations from 9.8m/s/s
1) Altitude. Increased altitude = decreased gravity
2) Earth spinning on its axis creates a centripital force which lessens gravity
3) Crust of the Earth isn't uniform. Where the crust is the thickest, gravity is highest
4) Distribution of dense elements in the universe isnt uniform
5) The Earth's globe is flattened at the poles. Gravity is stronger at the equator than at the poles
6) Air resistance.

Hope this helps!!!

 

[currysauce]

helstar! ur a champion...

hey do u do chem... if so... the fermentation prac... what would the variables be?

or if u do bio... in the pH concentration of CO2 prac... what are the variables!! thanks man!.. or girl

thanks!!!!

 

[fi_babezy]

Woot!!! I'm doing this prac for physics in about a week!!



Can anyone suggest some adjustments to my experiment template below. I wasn't there for the prac....should i see if i can actually do it b4 the prac test?

 

[fi_babezy]

Aim:
Use a pendulum to calculate the acceleration due to gravity on the surface of the earth and explain possible sources of variation.

Materials:
#retort stand, clamp and bosshead
#string (about 1.1m)
#stopwatch
#small ringed mass
#metre rule

Method:
1. Tie the end of the string and attach to the clamp so that the pendulum length is 1.0m. Adjust the clamp to the retort stand so that the mass can swing freely at the side of the bench.
2. Pull the mass slightly to one side of the stopwatch to measure the time taken for 20 oscillations. Record your result.
3. Repeat the experiment for successive shorter lengths of string to about 10cm. Record results.
Results:
Length (cm) Time for 10 swings (s) Period of pendulum (s) Period² (s²)






Or
20T(s) T(s) T² (s²) L(m)





Calculations
1. Plot length(y-axis) against period(x-axis) for your results.
2. Plot length (y-axis) against period² (x-axis) for your results.
3. Draw a straight line (of best fit) through the points as appropriate. Determine the slope of the line and the value of acceleration.

Conclusion
1. What is the value for acceleration due to gravity as indicated by your results?
2. What difference to your results would occur if you had used a heavier mass?
3. Explain possible sources of variation from 9.8m/s.

 

[TimeAndTide]

You need a constant angle of deviation for the pendulum so you can obtain accurate oscilations with the same amount of oscillations.

 

[Helstar87]

PH concentration of CO2

I do Biology and Chemistry. We havn't done the fermention prac yet, sorry. Maybe someone else has though. We have done the PH concentration of CO2 but I was away when we did it. I'll borrow someone's book though...
Ok so...
Aim:- To measure the effect of carbon dioxide on PH of water
Method:- 1) Put equal amounts of distilled water into 5 evaporating dishes
2) Add equal amounts of universal indicator into each dish.
3) Using a straw, blow air (carbon dioxide) into each of the solutions and observe the change in colour. The change in colour indicates a change in the PH level of the solution.
Results:- The water went from a nuetral PH colour to a more acidic PH colour, an orangy red colour.
Conclusion:- Corbon dioxide dissolved in water increases the acidity of a solution. This is a problem for the cells because the enzymes can only function properly at an optimum PH. This efficient enzyme activity can't occur in acidic PH environments, they need a neutral environment.

Hope that helps, as I said I wasn't there so I hope it's what your after

P.S. I'm a girl!!