Abstract
Have you ever wondered how a chick breathes inside its shell? Every animal needs oxygen to survive, so the chick must get air somehow! Try this science project to discover the answer.Objective
Determine if the pores in a chicken egg shell allow water to enter by weighing eggs before and after hard boiling.
Introduction
Every animal requires oxygen to live. When animals, including humans, breathe in, oxygen enters the lungs, where it is shuttled into the blood stream and distributed to all the different parts of the body. The oxygen is used in an internal chemical reaction called metabolism to provide the animal with energy. The process of metabolism also produces a waste gas called carbon dioxide. In order to get rid of this waste gas, the blood stream carries the carbon dioxide back to the lungs where it is collected and finally breathed out.
Animals that grow inside their mothers, like humans, get their oxygen from their mothers. The blood stream of the baby animal and the mother are connected through an umbilical cord, which allows the baby to collect oxygen that his or her mother breathes in and use the mother's lungs to get rid of the carbon dioxide. But how do animals that grow in a shell and do not have umbilical cords, like chickens, take in oxygen and get rid of carbon dioxide?
Bird and reptile eggs have a hard shell. Directly under the shell are two membranes. When the eggs are laid by the mother, they are warmer than the air, and as they cool, the material inside the egg shrinks a little bit. This shrinking pulls the two membranes apart, leaving behind an air cell, also called an air sack, that is filled with oxygen. As the animal develops, it needs the oxygen replenished so it can continue to grow, and it needs the carbon dioxide it's making to be able to escape from the air cell. So, how does this happen? Well, if you examine a chicken egg carefully with a magnifying glass, you'll see that there are tiny little holes, called pores, in the shell. A chicken egg shell has more than 7,000 pores! Do you think that the pores could be a way for carbon dioxide to escape and fresh air to get in? In this science project you'll determine if substances can move in and out of an egg through these pores. To do this you'll weigh several raw chicken eggs. Then you'll cook them in water and weigh them again. If the pores really do allow materials to cross back and forth between the inside of the egg and the outside environment, then the air inside the egg should be replaced by water, and water is heavier than air. Ready to find out the answer? Let's get cooking!
![]() |
| Figure 1. This diagram shows different parts of the egg. Notice the air cell, which forms between the inner and outer membranes. |
Terms, Concepts and Questions to Start Background Research
Bibliography
These websites have more information about breathing, oxygen, carbon dioxide, and metabolism.
Materials and Equipment
Experimental Procedure
| Raw Weight (g) | Hard-Boiled Weight (g) | Was there a change in weight? (increase/decrease/no change) | Change in Weight (g) | Observations During Heating | |
| Egg #1 | |||||
| Egg #2 | |||||
| Egg #3 | |||||
| Egg #4 | |||||
| Egg #5 |
Variations
Credits
Haleh Khoshnevisan, MedImmune
Sandra Slutz, PhD, Science Buddies
Last edit date: 2008-07-23 12:00:00
If you like this project, you might enjoy exploring careers in Zoology.
![]() |
Zoologist and Wildlife Biologist Ever wondered what wild animals do all day, where a certain species lives, or how to make sure a species doesn't go extinct? Zoologists and wildlife biologists tackle all these questions. They study the behaviors and habitats of wild animals, while also working to maintain healthy populations, both in the wild and in captivity. |
![]() |
Animal Breeder Why is it that certain breeds of cattle produce more flesh or milk? Why is one horse faster than another? The answer is that these breeds were engineered to have these special characteristics. Animal breeders need to understand genetics in order to produce animals that are bigger, faster, or more beautiful. If you are interested in working with animals and are fascinated by the science of genetics, then you should investigate this career. | |
![]() |
Biologist Life is all around you in beauty, abundance, and complexity. Biologists are the scientists who study life in all its forms and try to understand fundamental life processes, and how life relates to its environment. They answer basic questions, like how do fireflies create light? Why do grunion fish lay their eggs based on the moon and tides? What genes control deafness? Why don't cancer cells die? How do plants respond to ultraviolet light? Beyond basic research, biologists might also apply their research and create new biotechnology. There are endless discoveries waiting to be found in the field of biology! | |||
|
Join Science Buddies
Become a Science Buddies member! It's free! As a member you will be the first to receive our new and innovative project ideas, news about upcoming science competitions, science fair tips, and information on other science related initiatives. |