Science Buddies: "Ask an Expert"

I did the experiment, and I got a result that my solution of the luminol mixture with the catalyze with the cold water(about 5 degrees Celsius and my solution with the hot water barely had any light. Was the experiment suppose to be like that?
Or did I do something wrong? If I did it correctly; then why does temperature affect the brightness of the solution? Can someone give me some links for my project and examples for where I can search for information?

Hi Utanova,
I am sorry to say that I do not know the specifics of this experiment so I can't comment on the results.
In regards to resources on the web, please try the key phrase "luminol chemical reaction temperature" in google or other search engines. There seems to be quite a few articles on the topic that may be of use.

Please let us know if you have any other questions of if there's anything else we can do to help.
Good Luck!
Willey

Hi Utanova,

Willey gave you some useful tips for finding out more about the effect of temperature on the luminol reaction. Taking a look at some of the websites that come up when you do the search Willey suggested will help you better understand your results. Given what you've read in your search, are you results what you would expect?

I also wanted to probe a bit more deeply into your results. How hot was your hot water? And how much time elapsed between when you started the luminol reaction in the hot water and you made your observations? One possibility is that the reaction happened so quickly that you didn't see it. But, whether or not that explanation is realistic depends on how hot the water was and how quickly you observed the solution.

Well, hi (Terik)tdaly
My hot water was about 50 degrees Celsius and I took the picture after about 40 seconds elapsed. And I also searched on google with the key phrases "luminol chemical reaction temperature" and I found other people who also did the experiment and their results were the opposite of mine's and in the sites, they didn't quite explain why did that happen.

"My conclusion is that a lower temperature makes the chemical reaction with luminol last a longer period then the warmer experiment," according to http://cssf.usc.edu/History/2014/Projects/J0614.pdf.
So does this conclusion from that research show that I took the pictures at a time that was too off, therefore, my results were different? I did see that the cup of the lower temperature had a longer period of time of brightness and the warmer cup did lose it's light when I took the picture with the setting of my digital camera to slow shutter speed and low light settings.

Hi Utanova,

The water temperature you used should have been fine. As you found out during your internet research, you would normally expect that the hotter water would lead to brighter reaction. I think the most likely explanation is that by the time you took the picture after 40 seconds, the glow from the 50C water test had decreased below the glow of the cold water test at 40 seconds. The fact that you saw the lower temperature test glow for longer than the warmer temperature test supports that explanation. So, make sure that you point out in your results or conclusion section that you noticed a difference in how long the glow lasted at different temperatures.

Here's the chemistry behind what's happening: Increasing the temperature of the water makes the light-producing reaction happen more quickly. Because that reaction is happening more quickly, photons (packets of light) are emitted more quickly. This makes the reaction appear brighter. However, because the reaction goes more quickly, the reactants are used up more quickly. As a consequence, the reaction stops sooner. But another way, at high temperature, the reaction is bright and brief. At lower temperatures, the reaction is dimmer but last longer.

Post back as you have other questions.

Thank You Terik

I have a question.

Can you make a more advanced question of "How does temperature affect the blue glow created by the chemicals?"

Hi,
Sorry about this, I am not sure I quite understand the question.

If you are looking to perform a more advanced version of the experiment, please consider one of the variation listed under the "Make it your own tab" https://www.sciencebuddies.org/science- ... eityourown

Please let us know if there's anything else we can do to help.
Good Luck!
Willey