Physics and Biology Practical Test (2 Viewers)

[Green Yoda]

Hey guys,
So in week 7 and week 9 my physics and biology test is coming up respectively.
I'm always paranoid when doing prac tests..they don't always go in my favour.

So can anyone give me tips on how to ace prac tests. Basically want to get at least 90%+ and ultimately 100%.
I don't fully understand validity, reliability, accuracy and how and what to write in discussions. I know briefly that reliability has to do with how many times the experiment was done, validity has to do with the variables(unsure here) and accuracy has to do with how close the results were to the actual result.

Also do I have to draw a line of best fit? How would I best do this?
Also if i make a mistake while doing the prac what do i do? Where do i state this? (validity or accuracy?)

P.S The topic for physics is The world communicates and for Biology An Local Ecosystem, can anyone suggest possible pracs that can be asked?

 

[InteGrand]

Hey guys,
So in week 7 and week 9 my physics and biology test is coming up respectively.
I'm always paranoid when doing prac tests..they don't always go in my favour.

So can anyone give me tips on how to ace prac tests. Basically want to get at least 90%+ and ultimately 100%.
I don't fully understand validity, reliability, accuracy and how and what to write in discussions. I know briefly that reliability has to do with how many times the experiment was done, validity has to do with the variables(unsure here) and accuracy has to do with how close the results were to the actual result.

Also do I have to draw a line of best fit? How would I best do this?
Also if i make a mistake while doing the prac what do i do? Where do i state this? (validity or accuracy?)

P.S The topic for physics is The world communicates and for Biology An Local Ecosystem, can anyone suggest possible pracs that can be asked?

You can find info about Lines of Best Fit on this thread: http://community.boredofstudies.org/18/physics/335522/line-best-fit.html

 

[leehuan]

Considering you're interested in a FIRST-hand investigation:

Validity - Does your actual experiment address the aim
Accuracy - How close are you to the theoretical result
Reliability - Is there consistency within your results

 

[Green Yoda]

Bump

 

[DatAtarLyfe]

Considering you're interested in a FIRST-hand investigation:

Validity - Does your actual experiment address the aim
Accuracy - How close are you to the theoretical result
Reliability - Is there consistency within your results

This.
A valid experiment is one where all the variables are controlled to maintain a fair test and an appropriate method and equipment is used to test the aim.

For reliability, just talk about how if its been repeated multiple times or not, and explain what repetition does to the results i.e. Repetition wields results that are consistent to demonstrate the result was not a one off (assuming the experiment is valid)

Lee's def of accuracy is spot on. Accuracy is affected by validity as well as shitty equipment (voltmeters not calibrated properly etc.)

For line of best fit, plot all your values on the graph as crosses. Then, draw a line so that there is the same number of crosses on top of the line as there is below the line. Experiment on MS excel and plot random data and line of best fit it.

 

[eyeseeyou]

You need to know how to "critically think" and notice trends in your experiment. Also understand the theory behind the practicals

Good luck

 

[Green Yoda]

Thank You!
Any other tips?

 

[eyeseeyou]

Know your variables PROPERLY and don't mistake independant for dependant and graph them properly. Heaps of people do it the other way around and that usually costs them a mark or 2 in the HSC

May I ask Rathin but why didn't you choose chemistry?

 

[Green Yoda]

Know your variables PROPERLY and don't mistake independant for dependant and graph them properly. Heaps of people do it the other way around and that usually costs them a mark or 2 in the HSC

May I ask Rathin but why didn't you choose chemistry?

Always hated chem, i just find it really boring and it just doesn't spark my interest.

 

[eyeseeyou]

Always hated chem, i just find it really boring and it just doesn't spark my interest.

Lol I've heard people saying they hate physics and like chem. Mainly because they think Physics is "hard" and there's quite alot of maths

 

[Green Yoda]

Lol I've heard people saying they hate physics and like chem. Mainly because they think Physics is "hard" and there's quite alot of maths

The hardest part of physics in terms of maths would be using scientific notation lol

 

[Shuuya]

Lol I've heard people saying they hate physics and like chem. Mainly because they think Physics is "hard" and there's quite alot of maths

Why the inverted commas, physics is hard

 

[Shuuya]

Tip: Make sure to manage your time really well, because I always find that I spend too much time on the actual prac and up stressing to finish the rest of the exam

 

[Nailgun]

The hardest part of physics in terms of maths would be using scientific notation lol

yeah lol, projectile motion is probs hardest overall, but like, it isnt very hard either

note: this really only applies for physics pracs, idk about bio
For prac tests, imo don't be afraid not to do the experiment if you don't have to
one of my physics teachers actually recommends never actually doing the experiment unless its absolutely neccessary lol
as in if it's something that you could do with theory, and you'd know the results, generally it's a lot easier just to go off that and make up the results (using like formula)
dont be a retard and make up results if you're not sure though lol

you'll save heaps of time, and it's not like you can get marked down for having too accurate results (although you should probably introduce some variation lele)

another tip is if you are running out of time/want to save time, instead of actually doing trials, just add some slight variation to the first result you got (make sure you did it properly though) and then happy days


tl;dr, being disingenuous can work in your favor lel


edit: also make sure you plot on the right axis (dependent on the y axis, independent on the x axis)
when they want you to use the gradient you may need to use the inverse of it so 1/m
if they ask you to show how you got the gradient of the graph use a gradient triangle

also make sure that if it's actually a curve then draw a curve of best fit not a line - this screws heaps of people over lol
usually if you know the mathematical model of whatever relationship you are graphing that makes it easier to recognise

 

[Green Yoda]

yeah lol, projectile motion is probs hardest overall, but like, it isnt very hard either

note: this really only applies for physics pracs, idk about bio
For prac tests, imo don't be afraid not to do the experiment if you don't have to
one of my physics teachers actually recommends never actually doing the experiment unless its absolutely neccessary lol
as in if it's something that you could do with theory, and you'd know the results, generally it's a lot easier just to go off that and make up the results (using like formula)
dont be a retard and make up results if you're not sure though lol

you'll save heaps of time, and it's not like you can get marked down for having too accurate results (although you should probably introduce some variation lele)

another tip is if you are running out of time/want to save time, instead of actually doing trials, just add some slight variation to the first result you got (make sure you did it properly though) and then happy days


tl;dr, being disingenuous can work in your favor lel


edit: also make sure you plot on the right axis (dependent on the y axis, independent on the x axis)
when they want you to use the gradient you may need to use the inverse of it so 1/m
if they ask you to show how you got the gradient of the graph use a gradient triangle

also make sure that if it's actually a curve then draw a curve of best fit not a line - this screws heaps of people over lol
usually if you know the mathematical model of whatever relationship you are graphing that makes it easier to recognise

Thanks for the response
confused about what u said about the inverse gradient.
also how would i know when to draw line of best fit or curve of best fit?

 

[Shuuya]

Thanks for the response
confused about what u said about the inverse gradient.
also how would i know when to draw line of best fit or curve of best fit?

Inverse gradient:

For example, if you plotted Mass on the y axis and Force on the x axis, then to find acceleration you would need to find the inverse gradient (as F/m would be 1/a)

Draw a curve of best fit if most of the points are not within the range of a straight line

 

[Nailgun]

Basically, when you plot a graph you must always follow the rules regarding the axis and whether it's independent or dependent, and by using the gradient of the line you can calculate something. A more concrete example (it's a HSC formula but w/e) is the pendulum practical, where you get a pendulum and basically work out the time of one oscillation (you change the length of the pendulum (independent) which affects the time (dependent)

 

[Green Yoda]

What possible pracs for physics: The world communicates; biology: A local ecosystem?

 

[Nailgun]

What possible pracs for physics: The world communicates; biology: A local ecosystem?

We had one where we were given those refracty mirror glass thingoes and a ray box, and we had to measure the angle of refraction and hence calculate the refractive index of the glass (jks maybe it was perspex).

 

[Green Yoda]

We had one where we were given those refracty mirror glass thingoes and a ray box, and we had to measure the angle of refraction and hence calculate the refractive index of the glass (jks maybe it was perspex).

hmm we may or may not get up to refraction..possibly as there is till 6 weeks left and we have finished sound waves (ch 2/5) already.