Science Buddies: "Ask an Expert"

I’m doing a science fair and using this project: “Crime Scene Chemistry: The Kastle-Meyer Test for Blood” My teacher told me to dilute it, just like it says in “Make It Your Own” Why would I need to dilute it? How does that relate to a real life crime scene? How do I us revise exact ratios in diluting it. Sorry, I’m new!!

Hello!

That's a really good question! Blood at a crime scene can get diluted in a lot of different ways. For example, blood can get diluted when it mixes with rain water, when someone tries to wash it away with cleaning solutions, or when it drips onto a wet surface like a towel. Diluting your samples from your science project simulates the diluted blood at a crime scene and it can tell you how sensitive the Kastle-Meyer test is. If the test can still detect the blood after you've diluted it 1:100 or 1:1000, that means that the test has a good sensitivity. You can dilute your samples by mixing them with water. For example, to dilute the potato juice 1:10, you could add 1 mL of juice to 9 mL of water.

If you have more questions or need more clarification, don't hesitate to post them here!
Katelyn

Thanks so much! Makes total sense!