Reflections

So in March, I will be teaching a unit on the Human Body: Skeleton and Muscles to my third-graders. I've just finished my first lesson plan for the unit (and have many more to come).

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Third Grade Science: “Bendable Bones”

Lesson Foundation:

Big Idea: Characteristics of our bones allow our bodies to function in specific ways.

Standard Course of Study:

Competency Goal 4: The learner will conduct investigations and use appropriate technology to build an understanding of the form and function of the skeletal and muscle systems of the human body.

4.02: Describe several functions of bones: Support. Protection. Locomotion.

Statement of Objective:

1. SWBAT infer that the acid has weakened the bone
2. SWBAT hypothesize what will happen to a human bone in acid
3. SWBAT relate that an unhealthy human bone can become like the soft chicken bone (for follow-up lessons)

Critical Content

• Vinegar is an acid – a sour substance that neutralizes bases
• Calcium is an important mineral (a nonliving, naturally occurring substance) in the body that makes bones strong
• The vinegar dissolves the calcium from the bone, so the bone is no longer strong and you can bend it

Materials:

• Cooked chicken bones (30)
• Glass jars (5)
• White vinegar
• Rulers (to measure dimensions of bone)
• Coloration chart (to measure color of bone)
• Scissors (to test how brittle the bone is)
• Gift-wrap ribbon (30 strips)
• Sentence strips w/ guided practice steps
• Results table handouts (30)
• Colorful posters: "Question --> WHY"; "Answer --> APPLY"

Preparation Suggestions:

• Use bones which are clean of meat to avoid bad odor from decaying meat
• If the bone does not change over 5 days, add more vinegar and leave it longer

Allotted Time: 45 minutes to set up time; 5 days for bones to soak

 

Lesson Implementation (45 minutes)

Anticipatory Set: (7 min)

• In this lesson, students are only allowed to refer to each other as Dr. [First Name]. Teacher will proceed to call them by their new names.
• Briefly ask them of what scientists do (make a list together)
• Make detailed observations
• Ask good questions
• Discover new things
• Allow students to have a chicken bone each (on a paper towel)
• Basic Guidelines/Expectations
• Do not eat the bones
• Bones must always remain on the paper towel on the table
• Or your bone is taken away and you watch your neighbor
• Instruct “scientists” to investigate bones with a ruler to see what they can discover and what answers they have about the chicken bone.
• Tell each table to come up with “one big question” about bones after anticipatory set.

Statement of Objective: (1 min)

• We are going to find out what bones are made of and why they look and feel the way they do (i.e. functions of the bone!)

Input 1: (7 min)

• Classroom discussion

INQUIRY-BASED:

• As scientists, have students think and share their biggest question about bones. Anybody have answers?
• What other questions do the scientists have about bones? Anybody have answers?
• Any statements or discoveries about bones? Always challenge WHY they think bones are that way.
• Tell students that vinegar is going to make the bones do something very special.
• What do they think the vinegar is going to do?
  (reveal it is highly acidic and will react with the bone in some special way; acid is a sour tasting substance that is very strong and found in common foods such as apples and pineapples – do they recognize the strong taste I’m talking about? Bases are opposite to acids and include foods such milk and yoghurt, as well as the Calcium that is found in all bones!)
  What do they think is going to happen to the bone? WHY do they think that?
• Use science journals to record data and observations; Pass out result table sheets to students. **Leave extra blank rows so some kids can add to the table if they want to measure for other independent variables (differentiation)

Modeling 1 – RECORDING THE DATA: (3 min)

• As scientists, before and after an experiment is done, everything has to be measured so we can see the difference. They also make predictions.
• MODEL how to fill in the table – pretend to measure the length of the chicken wing, then, after asking students which column to write it in, fill out the “before” section. Proceed to fill in the “prediction” (based on student opinion – then exaggerate by saying I predict the chicken wing will grow 10 times the size).
• Explain list of materials and how to use them
  DEFINITIONS:
  coloration – finding the exact color of something by comparing it to a color scale;
  brittle – how easy it is to break or snap

	Before	After	Prediction	WHY
Length (cm)
Width (cm)
Coloration
Bendable?
Breakable/Brittle?

Check for Understanding: (2 min)

• Have students share their “predictions” with their partners/class (and rationales)
• Teacher circulate the room to look at students’ results tables

Modeling 2 – MAKING THE SOLUTION: (10 min)

• Model the directions to make solution, placing sentence strips with easy steps for making solutions on the board.
• Split up responsibilities so that one student at each table is in charge of reading instructions, one ensuring bones are correctly tied (with ribbon), one handling the vinegar (and one to hold the jar if there are four people at the table). Have students decide who will do what and raise hands when I call out each responsibility. ALL students clean up J

Guided Practice/Independent Practice (10 min)

• Cooperating teacher circulate between two tables; Me between three
• Making the solution by tables (5 tables) and placing their chicken wings inside

Closure/Assessment: (5 min)

• Now that they’ve completed the experiment, what is “the biggest question” that students have about what is going to happen to the bone? And WHY – recap the WHY reasons that we came up with before the experiment.
• While leading discussion on their biggest answers, ask them how it APPLIES to their lives (colorful posters of Question --> WHY; Answer --> APPLY).
• Discuss the role of Calcium in our bones: to be used by our muscles when we move or do exercise; therefore, it needs to be replenished by milk and other Calcium-rich foods. If we don’t have enough calcium, the bones will become very weak and be easily attacked by acids.

Next Time: take the bones out (at day 2 and day 5) and record results. Have discussions that compare their estimates with actual results.