Forensics Day 5: #bloodyfriday

Yesterday was “Bloody Friday,” and goodness did we have fun with it.

We started off with a fake blood competition–students used this recipe (and added their own modifications) to make blood that looks the most real.

Then we looked at blood spatter patterns using this lab here in which we check out how the height the blood was dropped from, the surface that it’s dropped onto, the angle it’s dropped at, and the speed at which it was dropped affects how it looks. They got SO into it–I mean, who doesn’t love a mystery with a bit of blood in it?

We then ended the day with a Nobel Prize Winning Blood Typing Game and a Skype call with a Blood Analyst from the Medical Examiner’s Office in NYC.



Yeast Balloon Lab

This is a fun yeast lab that can be used to teach about Fungi in a Taxonomy unit, or to teach about anaerobic respiration in the Cellular Respiration Unit, or just  as a simple introduction to inquiry:

Fungi yeast balloon lab

It focuses on how much CO2 yeast produce in environments with different amounts of sugar in them. My students generally found that the yeast produced the most CO2 for 1mL and 5mL of sugar solution.

To make it inquiry-based:

  • have them first complete this lab, and then ask them the question: what else could affect the rate of yeast CO2 emission?
  • I would suggest leaving the amount of yeast the same, and then changing either the amount of sugar (make the measurements more specific), the amount of sunlight, or the temperature of the water

Thoughts and Tips:

  • students need to know how to make a wet mount slide prior to this lab
  • it’s best if this is done during a lab block (80-ish minutes)–it will take them about 30 minutes to set up, and then they’ll have 40 minutes for data collection
  • pre-heat the water for the yeast to about 90C so that the students can get started with the lab straightaway
  • have the students heat up the water as they’re stirring the sugar in to get more of it to dissolve

From the Students:

“I have never done any labs in my past years in science and it felt like an actual experiment was occurring and it was a very interesting topic”

“It was cool to see something blow up with touching it”