Tuesday, June 24, 2014

STEM: Luminol experiment

This experiment is a fun way to simulate a crime scene where luminol is used to detect blood. An adult will need to help with breaking the glow sticks.

A few large glow sticks
Hydrogen peroxide
Paintbrush or Q-tip
A little bit of ketchup or paint
2 rocks

First, an adult needs to set up the two rocks , one rocks will be painted with ketchup, and one with the  contents of a glow stick. Here's how :

1. Very carefully cut the end of a glow stick off, do not not cut into the inner glass tube.

2. Now carefully slide out the inner glass tube and rinse it off ( the liquid around the tube is hydrogen peroxide)

3. In a small bowl with a lid, carefully break the glass tube by squeezing gently with a pair of pliers. use the lid while breaking the glass to prevent glass from flying everywhere.

4. paint one rock with the glow stick innards.

5. Paint the other rock with some ketchup or craft paint. Now time for some fun with the kids.. 

Add a squirt of Hydrogen peroxide to both rocks. It will fizz a little on each. Now turn off the lights...and the "guilty" rock will glow!

This simulates what happens when Crime scene investigators spray Luminol on an area and The Luminol reacts with the iron in hemoglobin. That chemical reaction gives off excess energy that is given off as a cold light, or Chemiluminescence. In a real crime scene, if investigators find a glow, that tells them they may have blood, and need to do further testing

The reaction that is happening in this experiment is very close. The insides of a glowstick reacts with hydrogen peroxide and gives off energy in the form of light.

This is a very fun demo to do, and produces a pretty spectacular glowing result . Use extra caution when handling the glass tubes, they do break very easily. 

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