Tackle a CO2 science mystery hundreds of years old as we venture into the Cave of Dogs.

The Cave of Dogs

Scan this QR Code with your Phyphox sensor app to load the CO2 sensor settings for all activities in the CO2 Science Series.

The Cave of Dogs

A Science Mystery

Explore Carbon Dioxide (CO2) and the properties of gases in fun and interesting ways as we create, capture, and study CO2 in a quest to solve a mystery that is hundreds of years old.

Overview

Grades:
Time:

 

Subject:
Topics:

5-8
50 minutes (PDQ’s + Experiment) 
50 Minutes (Challenge & Collaboration)

Chemistry
Properties of Gasses, Chemical Reactions

 


Get ready to stir up some fizzy, bubbly
chemical reactions while you explore properties of gases that create some thought-provoking real-world phenomena!

Background

Imagine a mysterious cave  that affects people and animals quite differently as they enter to explore. Such a place actually exists, it is called the Cave of Dogs and it is located near Naples, Italy. The “mystery” of the cave is how it affects different animals.  A human can enter and walk about with no problem, but dogs or other small animals that enter pass out. Yikes!

The answer to the mystery?  If you haven’t already guessed, the more dense CO2 gas settles into the lower areas of the cave and animals that are close to the ground asphyxiate – there is no oxygen! Humans, walking upright, are above the CO2 level and able to breathe in the life-giving oxygen that CO2 displaces at a lower level. This mysterious cave has a fumarole from which volcanic gases including CO2 seep into the cave making it a very dangerous place to be if you want to be able to breathe!

Let’s explore further with databot™!

A fumarole is a volcanic vent that emits gases such as CO2.

Objectives

Understand & Recognize:

  • A chemical reaction is when two substances react with one another to create a new, different substance
  • Chemical reactions can cause physical and chemical changes in substances – even creating gas where there was none before.
  • Gases have weight, and different gases are heavier or lighter than others.
  • A fumarole is a volcanic vent, an opening in the earth’s crust, that emits steam and gases.
  • CO2:
    • Is an invisible and odorless gas.
    • Deadly to animals in concentrated amounts.
    • Heavier than air.
    •  Exhaled by human beings.
    • Levels can vary in the air around us depending on many factors.
    • It can be generated through a chemical reaction of baking soda and vinegar.

What You'll Need

  • Android smart device with Bluetooth Low Energy (BLE) to connect to databot™
  • databot™ + Phypox App installed on your Android device
  • Plastic Bottle – 2 Liter
  • Paper clips- 5
  • Binder clips – 3
  • Tea Candles – 3
  • Funnels to control your pours!
  • 12” round balloons (3 or more to be safe)
  • White Vinegar
  • Baking Soda
  • Vase or Jar large enough to hold candles and blocks.
  • Lighter (long-handled)
  • Blocks – LEGO works well.
  • Yardstick + Cloth Measuring Tape
  • Pencil or Dowel + a Heavy Book / Weight

Important Terms

Carbon Dioxide (CO2): A colorless, odorless gas naturally present in the air you breathe and is absorbed by plants in photosynthesis. There would be no animal life or green plants without carbon dioxide. Green plants use energy from the sun plus carbon dioxide and water to produce carbohydrates and oxygen.

Weight: is a measurement of the force of gravity applied to an object – it is calculated by multiplying an object’s mass by the acceleration of gravity. The weight of an object can vary depending on the gravitational field it is in.

Volume: The amount of space a substance takes up.

Density: An object’s mass in a given volume. For example, a 1 cm cube of gold is much denser than a 1 cm cube of balsa wood so the weight of the gold cube is much, much heavier.

Chemical Reaction: This occurs when substances combine to produce one or more new substances.

Reactant: The starting substance that enters into a chemical reaction.

Product: The substance created in a chemical reaction.

Fumarole: An opening in the Earth’s crust through which volcanic fumes are emitted.

Prep

Read the background information, study the terms, and explore the additional resource links.

Ready to get started? Let's go!

Next stop – PDQ1 – that means Pretty Darn Quick. Go dog, go!

This way to PDQ1

Educator Info

Educator Info

  • Read the background information, study the terms, and explore the additional resource links.
  • Do the PDQs and Experiment and review the accompanying educator information.
  • Review the Challenge and Collaboration extensions if of interest.  

This science mystery is all about Carbon Dioxide (CO2), an important gas that is an integral part of our ecosystem. Plants eat it, we exhale it, and too much of it can be harmful!! In this module the activities explore a specific property of gases – gases have “weight.”  CO2 is heavier than air which is illustrated in PDQ 2 as students actually see air being weighed against CO2.  The first PDQ is the always popular baking soda and vinegar reaction, but it is done with a simple apparatus that enables students to capture and store CO2 in a balloon. The actual Cave of Dogs experiment is a dramatic demonstration of CO2 putting out candles as CO2 is released from the balloon and slowly fills a simulated “Cave of Dogs” extinguishing candles placed at different heights.

*Important note – some students get upset about the thought of animals being injured in the cave so treat the topic with sensitivity!

The Cave of Dogs experiment is an engaging and fun experience for students as we facilitate a chemical reaction that gives off CO2 that is captured in a balloon enabling us to replicate the mysterious Cave of Dogs scenario. From the reaction and experiment, students see and experience the following:

 

Understand & Recognize:

  • A chemical reaction is when two substances react with one another to create a new, different substance
  • Chemical reactions can cause physical and chemical changes in substances – even creating gas where there was none before.
  • Gases have weight, and different gases are heavier or lighter than others.
  • A fumarole is a volcanic vent, an opening in the earth’s crust, that emits steam and gases.
    • CO2:
      • Is an invisible and odorless gas.
      • Deadly to animals in concentrated amounts.
      • Heavier than air.
      •  Exhaled by human beings.
      • Levels can vary in the air around us depending on many factors.
      • It can be generated through a chemical reaction of baking soda and vinegar.
  • 5-PS1-1: Develop a model to describe that matter is made of particles too small to be seen.
  • 5-PS1-4: Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
  • MS-PS1-2: Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
  • NGSS Practice 4: Analyzing and Interpreting Data
    Excerpt: When possible and feasible, students should use digital tools to analyze and interpret data. Whether analyzing data for the purpose of science or engineering, it is important students present data as evidence to support their conclusion.
  • Air has no weight
  • Why do the candles go out from the bottom up?
  • Why do you suppose the cave is more dangerous to animals than people?

The Grotta Del Cane (Dog Cave), Naples, Italy
Article, W.R. Halliday; Arrigo Cigna. January 2006
https://www.researchgate.net/publication/290890558_The_Grotta_Del_Cane_Dog_Cave_Naples_Italy

Cave of Dogs
Illinois Library, Rare Book and Manuscript Library
https://www.library.illinois.edu/rbx/2016/12/15/cave-of-the-dogs/

Atmospheric Pressure, the weight of air
WW2010, University of Illinois
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/prs/def.rxml

Carbon Dioxide
Wikipedia
https://en.wikipedia.org/wiki/Carbon_dioxide

Balancing Balloons, Air Has Weight
Fun Science Demos with Jared, Youtube Video
https://www.youtube.com/watch?v=o5LT_wfI98wCave of Dogs

NASA, Does Air Have Weight? How Do You Know?
A Structured-Inquiry Activity
https://www.nasa.gov/centers/langley/pdf/245898main_MeteorologyTeacherRes-Ch7.r3.pdf

Fumarole Image by Monika P on Pixabay!

The Cave of Dogs by Robert O. Grover & Team databot

© Copyright. aRbotics LLC. 2020. All rights reserved.