Highschool Chemistry Help

[Guest InfinitZero]

Well I've been looking all over the net for some info on transmittance in like light but I keep getting unrelated information about astrophotography and other crap.

 

Anyways let me explain my dilemma. Im a highschool student and for chemistry its mandatory to do a science fair project.

For my topic I'm seeing if Hydrogen Ion Concentrations (pH) affect the colourants of fruit juices.

I already know that it does.

 

Anyways I made a buffer solution and filled 10 separate beakers with it. I adjusted the pH from 1-10

 

I added four mL of the buffer to one mL of the fruit juice

 

I did this for a few juices and asked my teacher to use the schools spectrophotometer to measure the change in nm for each of the 10 pH's when added to the juice.

 

I didn't know much about my topic at the time. Anyways like I said I wanted to measure the change in nm but for some reason my teacher wanted me to measure the transmittance at the three wavelengths (green,blue,red)

 

Anyways so the data I got was in percents. I dont really understand this concept of transmitance. I know that the juices should turn redder when mixed with an acidic solution and bluer with a basic solution. So if I'm measuring the change in cranberry juice on the red wavelength would a transmittance percent around 100% mean it was darker than a percent around 80 or is it vice versa.

 

If anyone could help explain this to me either through this post or through an e-mail it would be very helpful. There have to be some science nerds here on maestra willing to help me

 

Im getting desperate lol due Monday.

 

And as for why my teacher wanted to measure the change in transmittance at the three wavelengths mentioned above rather than in nm I don't know. Hes a pompous arrogant guy who thinks he knows everything when really he doesnt know that much at all lol.

 

Basically I wanna know based on the transmittance data I collected in the three wavelengths for each juice how can I graph this data or show how it changed.

The change was very small in some juices but it was big in others.

 

any help is really appreciated

btw im taking a grade 11 university chemistry class in Ontario,Canada

[Guest InfinitZero]

should I maybe post this in a different category?

[TimeTraveler]

You probably should have posted this in the homework help or chemistry section, but I would not repost it now, I am sure a moderator will kindly move it to the right section for you.

[Guest InfinitZero]

when I posted it i quickly glanced over the different forums I didn't even see a homework one..hmm i think ill go exploring now

 

I re-posted in the chemistry forum. The mods can delete this thread if they want.

 

thx for the info timetraveler and sorry for any inconveniences