Passive Blood Labs

Blood patterns made from falling drops of blood

Lab 2: Falling Blood Drops in Motion

During this lab, you will see how motion affects the size and shape of the droplets and spines. You will need a long piece of butcher paper (4-5 meters in length) and tape to secure it to the floor.

Experiment

To do the lab, you will need to hold the dropper bottle upside down so that your hand is out and away from your body (waist level), but is still over the paper.
Start off walking at a SLOW WALKING RATE along the paper strip from one end to the other and GENTLY squeeze the bottle as you walk so that blood is released ONE DROP at a time. Be sure that all the drops land on your paper strip.
Repeat this procedure using a NORMAL WALKING RATE and a FAST WALKING RATE.
Take a picture of a quality droplet, upload these with your responses to the lab questions
When you are done, analyze your results and answer the questions on your worksheet. Clean up your area and put away your materials before you leave class.

Lab 2 Questions: Answer on your Blood Page

What did you notice about the shape of the droplets as you increased your walking speed?

What did you notice about the spines as you increased your walking speed?

What did you notice about the distance between the droplets as you increased your walking speed?

Lab 1: Falling Blood Drops

Objective:

In Part I, you will examine the relationship between height and velocity as well as height and blood drop diameter.

Procedure:

Using a dropper, allow a single drop of blood to drop from five different heights: 5 cm, 25 cm, 50 cm, 75 cm, and 100 cm onto a sheet of paper. Complete the following:

Set Up

Make a copy of this Google Sheet, share it with Mr. Miller
Set up the lab materials
- You'll need blood, a dropper, paper, and a meter stick
- You'll drop 3 drops of blood from 5 different heights

Experiment

Label your paper and drop 3 droplets of blood from each height (.05, .25, .5, .75, 1.00 meters)
Calculate the final velocity using this handy free fall calculator.
- Enter the height (In METERS, not CM!) and enter 1 as the mass. (doesn't affect the velocity)
Measure the diameter of the drops.
Count the number of satellites (separate droplets)

Analysis

Calculate averages for diameter and number of spines
Make 2 graphs: Drop Height vs. Velocity and Drop Height vs. Diameter
Answer the questions below on the spreadsheet

Turn In

Embed the spreadsheet on your Blood page

Lab 1 Questions: Answer on your Blood Page

Make conclusions about the 2 graphs you made. Use quantitative data in each.

How do the spines compare from the different heights? Be descriptive.

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