Senior Science Discussion Thread

[kawther]

Hey

Can anyone tell me what to write for the history of a pacemaker?

thanks

1950s - pacemakers were large external devices that worked on AC
1960s - implanted pacemakers with longer life batteries. Sensors were used to detect when the heart was beating so pacemakers provided pacing when necessary
1980s - 1990s- computer technology enabled programable settings in pacemakers
2000s- pacemakers now collect and store information in memory.

Hope this helps! 

[MEL7401]

Hey!
I'm Year 11- does anyone have any effective ways/tips to study for Senior science???

[jamonwindeyer]

Hey!
I'm Year 11- does anyone have any effective ways/tips to study for Senior science???

Hey Mel! Welcome to the forums

Not for Senior Science specifically, but you should give this a read! It's a big list of creative and powerful study methods besides that - Stay organised, do little bits at a time, write your notes as you go (if you need notes), and do lots of practice!

[MEL7401]

Thanks!

[JD99]

Hey flashcards work really well for Senior Science, as they help memorize the TONNES of definitions!!


from a fellow Senior Science student!!

[JD99]

Oh and I also should have mentioned that Dotpoint books are AWESOME!! just remembered when I started using mine!
it has exam style questions on every dotpoint from the syllabus! very handy!

[biffi023]

hey 
can anyone pls describe anionic, cationic, non-ionic and amphoteric for me in basic terms?.. and what I really need to know about each of them?? i have what kind of charge each one of them is so i can memorise that.. but dont know what they actually mean or what they represent in real life etc..
thanks ppl 

[ella.suggate]

Hello

Just wondering if someone could please help me out on understanding the ionisation of a drug in the lifestyle chemistry topic.

Thanks!

[Jenny_trn]

Hi!
Does anyone know the response to this point: 'identify the transformation of energy at each stage of information transfer in the following device' but for  Mobile Phones?

Thanks!

[marcorabbitolol]

Hi!
Does anyone know the response to this point: 'identify the transformation of energy at each stage of information transfer in the following device' but for  Mobile Phones?

Thanks!

do u mean this?
sound-electrical (sent to switching centre)-electromagnetic (microwave)- electrical- sound
or
sound-coded in mic- transmitted via microwaves from tower to tower- detected by receiving mobile- decoded- sound

i think they r basically the same- just 2 sets of notes saying 2 different things (always ideal the night before the exam)
hope that helps

[Jenny_trn]

do u mean this?
sound-electrical (sent to switching centre)-electromagnetic (microwave)- electrical- sound
or
sound-coded in mic- transmitted via microwaves from tower to tower- detected by receiving mobile- decoded- sound

i think they r basically the same- just 2 sets of notes saying 2 different things (always ideal the night before the exam)
hope that helps

yeah, thank you! I was looking for the first one, the second one refers to the information transfer process dotpoint.

[zanibalh]

guys im so confused, is an emulsifying agent and an emulsifier the same thing? or are they different because I have different explanations for both.
it'll also be great if someone could clarify what an emulsion is.

[Kate Science]

guys im so confused, is an emulsifying agent and an emulsifier the same thing? or are they different because I have different explanations for both.
it'll also be great if someone could clarify what an emulsion is.

Heya! You're absolutely right to be confused - science terms get so frustrating! But there is a difference between the two.

So an emulsifying agent is the chemical that allows the emulsion to form (allows the dispersion of oil droplets in water or vice versa).
But an emulsifier is a chemical that stabilises that emulsion once its formed (by increasing the kinetic stability of the particles).
For example, egg yolks are used as an emulsifier in mayonnaise to keep the oil from separating out. The emulsifying agent is lecithin.

And to clarify, an emulsion is a dispersion of tiny tiny droplets of oil in an a watery solution OR tiny tiny droplets of a watery solution in an oil. If you poured some olive oil into a half filled water bottle - the two liquids would form two layers because they are "immiscible" (they do not mix). Crack an egg inside and shake it up for a while - you get mayonnaise!! Mayonnaise is a mixture that has the water and oil components in the drink bottle mixed evenly and the two liquids no longer have separate layers. That's an emulsion.

Other examples include:
Milk (watery liquid with tiny drops of fat (i.e. oil) dispersed)
Cream (fatty liquid with tiny drops of water dispersed in it)

Hope that helps!

[zanibalh]

Hey guys,

For information systems, how does total internal reflection relate to optical fibres?
& is there a communication process for optical fibres?

[jamonwindeyer]

Hey guys,

For information systems, how does total internal reflection relate to optical fibres?
& is there a communication process for optical fibres?

Hi! Optical fibres use total internal reflection to transmit data at the speed of light. Essentially, we take a light signal and modulate it (meaning change its amplitude or frequency) as a way to represent bits of information (say, 1's or 0's in binary). We pass it into an optical fibre, and it travels along it, bouncing from wall to wall - This is total internal reflection. We detect it at the other end and decode the modulation to figure out what was sent in the first place - Hey presto, you've got NBN, or whatever we're using it for.

The comms process (I didn't do SS so this might not be what you need) is the same as pretty much any other communication system. Take your data, code it (that's the modulation), transmit it (total internal reflection), decode the message at the other end (demodulation) and then use the information