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How well does a cloth cover stop sprayed droplets?
Credit: CITIZEN SCIENCE: Eichler, Hopperton, Alava, Pereira, Ahmed, Kozlakidis, Ilic and Rodriguez-Palacios. This is an open-access
article distributed under the terms of the Creative Commons Attribution License (CC BY).
Recommended Grade Level(s):
Appropriate for: Middle and High School
Time Requirements:
30 minutes
Teaching Topics & Concepts:
Cloth can stop the spread of sprayed liquid droplets.
Background:
The goal of the experiment is to determine how many macroscopic (visible)
droplets get past a face cover and reach a surface.
Materials:
• 1 spray bottle
• Enough dark soda, cold coffee, or sports drink to fill a spray bottle halfway
• 14 pieces of letter sized white paper
• A large empty space on a table or washable floor
• 1 empty cereal box
• Scrap cloth about 10" x 10"
• Scissors
• Silverware, a soup can, or other objects to be used as weights
Procedure:
1. Cut 2 approximately 4" diameter windows on both sides of the box as shown in the pictures above so that the spray bottle
nozzle will be at the level of the holes when placed flat on the ground. If this is not possible, cut the windows as high up as
you can get them.
2. Tape a single layer of cloth/textile over one of the windows.
3. Secure the box in upright position by placing heavy objects such as utensils, soup can, or other inside
4. Place 7 pieces of paper on the floor or table long end to end, number them 1–7 (1 is nearest the spray bottle).
5. Place the box directly in front of paper 1 with no space in between and set the spray bottle flat with the nozzle pointed
to spray through the box and through the cloth. If the bottle is too large just angle the bottle so the stream is as close
to horizontal as possible.
6. Give one complete spray. Remember to wait 30 seconds to let droplets fall. Observe the spray pattern and answer the
questions. Save the box for use in other experiments.
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