Science Buddies: "Ask an Expert"

Hey guys. I am doing a project in which I want to make a lotion type substance with chemicals in them to react with bacteria to alert people of their presence. I was just wondering if there was any way I could measure the change in color of the substance quantitatively? I am unable to use a spectrometer since my bacterial colonies would be on agar. Thanks for your time guys!

Hi Atreya,

There are a couple options that might help you. One is to carefully harvest your colonies from the agar and suspend them in liquid medium so you can use a spectrometer. Another option is to take high-quality digital photographs (with controlled lighting and positioning) of your petri dishes, and use Photoshop to quantify the color of the colonies.

I hope that helps. Please post again (in this same thread) if you have more questions.

Heather

Thanks so much for your quick help! I will definitely try the photoshop idea. It seems like a great idea. I would also try the suspension in a liquid medium but it might possibly change the color further of the dye, but photoshop seems like it would work. Thanks agin so much for your help!