Boning Up on BARF
Stage 1 – Desired Results
Content Standard(s):
Grade 5
Standard 3.0 Life Science: The students will use scientific skills and processes to explain
the dynamic nature of living things, their interactions, and the results from the interactions
that occur over time.
B. Cells
2. Investigate and provide evidence that living things are made mostly of cells that can be
seen and studied only through a microscope.
b. Use microscopes and pictures to investigate, describe with drawings, and compare the
cells in a variety of multicellular organisms, such as cells in elodea and onions, muscle
cells, nerve cells, skin cells, etc. in animals.
Grade 7
Standard 3.0 Life Science: The students will use scientific skills and processes to explain
the dynamic nature of living things, their interactions, and the results from the interactions
that occur over time.
B. Cells
2. Recognize and provide examples that human beings, like other organisms have complex
body systems of cells, tissues and organs that interact to support an organism's growth and
survival.
b. Select several body systems and explain the role of cells, tissues and organs that
effectively carry out a vital function for the organism, such as
Understanding (s)/goals
Bones contain different substances, some of
which make them strong, others make them
flexible.
Essential Question(s):
How do different chemicals affect bone
material?
Why does the mass of the bone change
when soaked in bleach?
Why does the mass of the bone change
when soaked in vinegar?
How do the characteristics of the bone
change by soaking it in bleach/vinegar?
Student objectives (outcomes):
Infer that changes in the mass of chicken bones that have been soaked in acid (vinegar) or
base (bleach) are due to the removal of substances that make up the bone.
Stage 2 – Assessment Evidence
Performance Task(s):
Other Evidence:
Measure and observe un-soaked bones.
Students will be able to apply knowledge of
Measure and observe changes in bone
materials making up bones to explain
material that has been soaked in chemicals. situations such as bone fractures and dried
bone material.
Stage 3 – Learning Plan
Learning Activities:
Engage: Mention that I have dogs that I want to feed well. Invite children to tell about what
their dogs eat. Present scenario about BARF (biologically appropriate raw food) dog diet
and the issue regarding whether it is safe to feed dogs fresh, uncooked chicken bones. This
leads to the question: How is the material in a dried/cooked bone the same as or different
from the material in a living bone?
Explore: Students will mass cleaned fresh chicken bones, observing the bone properties
and measuring its mass. They will predict what will happen to the bones over time when
they are soaked in bleach and vinegar.
Procedure: Remove and clean a fresh chicken bone (humerus) from a chicken wing
Remove as much of the soft tissue as possible
Mass the bone
Predict what will happen to a bone that is, a) soaked in vinegar, b) soaked in bleach
Debrief: See questions
What is the difference in mass between the unsoaked and soaked measurement?
What does this suggest happened to the bone?
What other observations can you make about the changes in the characteristics of the
bone?
What do the changes in characteristics of the bone suggest happened to it?
Explain:
The vinegar dissolves the calcium compounds (calcium phosphate) in the bone, leaving the
collagen proteins. This makes the bones flexible.
The bleach dissolves the collagen proteins, making the bones very brittle.
Evaluate: Describe how it is possible for someone to do a high jump without their bones
either cracking or folding under them.
Elderly people often have problems with their bones breaking easily. What can you infer
about the substances in their bones that would explain this?
Exit ticket:
How do different chemicals affect bone material?
Online Resources:
BARF (Biologically Appropriate Raw Food)
http://www.barfvictoria.com.au/philosophy.html
http://www.americandogtreats.com/barf-diet-benefits.asp
http://www.americandogtreats.com/raw-dog-food-treats.asp
http://www.rawlearning.com/rawfaq.html
http://www.daybreakaussies.com/raw_feeding.htm
http://leerburg.com/feedingarawdiet.htm#chickenbones
Bone Labs
http://weirdsciencekids.com/Rubberchickenbone.html
http://www.wackyuses.com/experiments/rubberchickenbone.htm
http://www.biology.usm.edu/biologylabs/materials/BSC250LCHICKENEXPERIMENT.doc
Opening Narrative:
Boning Up on BARF
I love my two dogs and, of course, want to do the best for them. Lately, I’ve been
hearing a lot about a special diet for dogs called BARF. It’s not what you think. In this
case, “BARF” stands for “Biologically Appropriate Raw Food.” It’s a special sort of diet
for dogs in which their menu consists of raw meats bones—essentially the sorts of things
that a wild dog might eat if he caught his own food. I like the idea. It seems like a lot of
the dogs’ BARF diet could be made from leftover scraps from when I prepare meat for
myself. But then I remembered that someone told me to never feed my dog table scraps,
especially chicken bones. I’ve been told that I should never feed my dog chicken bones
at all. Then I wondered, about the difference between raw chicken bones and cooked
chicken bones. Maybe raw chicken bones are OK to feed to my dog. I wondered
whether, if I go to a BARF diet for my dogs, I can feed them chicken bones at all. This
led me to some questions.
What are chicken bones made of that might help or hurt my dog?
What does cooking do to a chicken bone?
Primary Resources:
BARF for Beginners
http://www.njboxers.com/faqs.htm
Firm But Flexible, Chicken Bone Labe
teachhealthk-12.uthscsa.edu/curriculum/bones/pa12pdf/1203C-THO.pdf
Living Bones Strong Bones
www1.nasa.gov/pdf/182815main_FE_LBSB_ED.pdf