Science Buddies: "Ask an Expert"

I'm wanting to do my science fair project on the Crime Scene Chemistry - The Cool Blue Light of Luminol, but I can't seem to find the control group. Is there a control group for this project? If not, should I change my problem, so there is a control group? It seems like many science fair judges want the control group, so I'd like to have one. Please reply ASAP!!

Hi studybuddy017,

A control group in an experiment is a standard to which comparisons are made to other groups. Other groups (treatment groups) have treatments applied to them that are not used in the control. If all goes well, differences observed between the control group and the other groups are due to the test treatments.

In the experiment that you asked about, you investigate the effect of temperature on the luminol reaction rate. To do this you conduct the luminol reaction at two temperatures. During the reaction you observe the changes in the luminol's blue glow over time. Then you compare your observations for the two temperatures.

Strictly speaking, there is no control group in this experiment. Instead, the temperature is the independent variable. But you might think of the low temperature reaction condition as a standard (or benchmark) for comparison with observations made at the high temperature.

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

A. Norman

I’m doing the science fair project called “crime scene chemistry- the cool blue light of luminol”.

Question: In the materials section it says I need “Digital camera that can take pictures in dim light (should allow for long exposures; for example, 5 sec)”. Can I use my IPhone to take photos or do I specifically need a good digital camera?

Please reply as soon as possible!! I’m kinda in a hurry

Hi studybuddy,
This question seems directly related to your previous post, so I'm merging it. That way, the expert who was helping you can continue to follow-up on your questions. Thanks!

Hi studybuddy,

You should be able to use an iPhone to take the photos for the luminol project. But you'll need to set the shutter speed manually. To do this you'll need to use an app that enables manual exposure settings (for example Camera+). The following links have more details on setting the shutter speed on an iPhoine.

http://snapsnapsnap.photos/a-beginners- ... ter-speed/

https://www.imore.com/best-apps-slow-sh ... hotography

Be sure to experiment with the exposure time as outlined in the project procedure. You want to set an exposure time that clearly shows the glow from the luminol in your photos. Once you've settled on a shutter speed, use the same camera position and exposure time for all the photos you take during your luminol experiments.

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

A. Norman

So I'm doing the Crime Scene Chemistry- The Cool Blue Light Of Luminol for my science fair project. I did all my trials but I'm having trouble graphing the data. I already made a graph data for the brightness and time, but I need to make another graph for brightness and temperature. I'm confused on how to create the graph (the groups, values...) Please Help!!

Hi StudyBuddy,
Please keep your follow-up questions together with your previous questions on the same science project. That way, the experts who have been helping you will see your new question and will be able to follow and help you.
Thank you.
Moderator

Hi studybuddy,

My suggestion is to put the brightness and time data for both temperatures on the same graph. That way you can easily see the effect of temperature on brightness as the time changes.

To do this first plot the brightness (on the y-axis) versus time (on the x-axis) for one of your temperatures. Now plot the brightness data for the other temperature. Be sure to use a color or symbol for these data that is different from the first set. And label both of the data sets.

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

A. Norman