Science Buddies: "Ask an Expert"

So I chose the topic see the light by making a spectrophotometer and it seems interesting enough. However it is more like a demonstration project. Is there an actual problem/testable question for it? If there is, then could you let me know? I need to know by tonight because I have to hand in the purpose, problem, hypothesis, materials, and variables tomorrow. So once again, the problem/testable question is what I want to know. Thanks

The experimentation in the project as presented has to do with detecting the absorbed light form the various colors of food coloring once you've made the spectrophotometer. I'm not going to define all of your variables for you, but it does seem obvious that by manipulating the coloring in the water you'll see different spectra.

Whether that's a sufficiently scientific experiment or simply a demonstration is kind of up to you.

Howard

Hey guys. For this experiment when I am taking the pictures of the spectrum, am I allowed to use the flash on my camera? Thanks

Hi TheFinalView,

No, you should not use the flash. For this experiment it is important that the only light be coming from the LED.

Let me know if you any other questions!

Hey guys. So in this project (See the light by making a cellphone spectrophotometer), what is the point of having the reference as the water? What is the point of having the reference in the software? I also need a control test in my experiment and I put it as water. However how would I be able to test the absorption spectrum of the control test, which is water, if i have to use the water as a reference? Because I would need the wavelength and absorption of water as well. Thanks and sorry if this sounds confusing.

PS

Is there an actual application to this experiment? Thanks again.

So, in this project the wavelength of maximum absorbance for blue is between 610-630 nm. WHy is this the case? Isn't blue supposed to have shorter wavelengths between 400-484? Isn't red supposed to have the longest wavelength and yet in this experiment it has a wavelength of 507-527? I need immediate help as I need to finish this type up TODAY so I can finish my display board tomorrow.

Hello. Please continue on the same thread instead of creating new threads, so that our experts can best answer your questions based on what has already been discussed. You have received excellent advice so far....good luck, and thanks for using Science Buddies!

Is there a real application to this experiment? Like after doing this blue came out with the highest wavelength but how would I apply this to real life? I don't think there is an actual application to this. If there is, can someone help me? thanks.

Hello TheFinalView,

A couple of applications of the “See the Light” project come to mind.

This project explores how visible light interacts with colored materials (in this case food colorings). You use a spectrophotometer to demonstrate that a blue dye transmits shorter wavelengths of light and absorbs longer wavelengths. Without this kind of interaction between light and substances that can transmit (or reflect) light, we wouldn't have any colors.

Spectrophotometers are widely used in chemical analysis. They can be used to measure the amounts of specific chemical compounds in solutions or mixtures. Also they can be used to help identify chemical compounds. The cell phone spectrophotometer from your project is a simplified version of instruments used daily in chemistry labs everywhere.

I hope this helps. Please post again if you have more questions.

A. Norman

I have entered my photo and reference into the downloaded program, but I cannot see the bottom of the graph on my screen. When I make it as large as I can, I get almost all of it, but the very bottom is not visible, and there are no scroll bars to scroll down.

How do I see the bottom of the graph?