Texarkana Independent School District
IPC – 1st , Biology – 3rd,
Chemistry – 1st
11th grade science
TIME ALLOTTED FOR INSTRUCTION:
Acceleration Due to Gravity
The student will demonstrate an understanding of motion, forces, and energy.
FOCUS TEKS AND STUDENT EXPECTATION:
11.4 The student knows concepts of force and motion evident in everyday life.
The student is expected to:
calculate speed, momentum, acceleration, work, and power in
systems such as in the human body, moving toys, and machines.
SUPPORTING TEKS AND STUDENT EXPECTATIONS:
Objective 1: The student will demonstrate an understanding of the nature of
11.1 The student, for at least 40% of instructional time, conducts field and
laboratory investigations using safe, environmentally appropriate, and
ethical practices. The student is expected to:
(A) demonstrate safe practices during field and laboratory investigations
11.2 The student uses scientific methods during field and laboratory
investigations. The student is expected to:
plan and implement investigative procedures including asking
questions, formulating testable hypotheses, and selecting equipment
(B) collect data and make measurements with precision
(C) organize, analyze, evaluate, make inferences, and predict trends from
(D) communicate valid conclusions
The student will understand that
Forces affect every object.
A force is any push or pull that one body exerts on another.
The force of attraction between the center of two objects.
The rate of change of velocity, which occurs if an object speeds up, changes direction, or slows down.
Any object dropped from a given height above the ground will accelerate as it falls because of gravity.
Terminal velocity is reached with air resistance (the upward force exerted on a falling object) equals acceleration due to gravity.
The acceleration due to gravity on Earth is 9.8 m/sec2 until the object reaches terminal velocity, at which time its velocity will be constant.
I. SEQUENCE OF ACTIVITIES (INSTRUCTIONAL STRATEGIES)
A. Focus/connections/anticipatory set
When students are seated, hold up two pieces of identical paper. Show students that the paper is identical.
Crumble up one sheet of paper. Hold the two pieces of paper at the same distance from the floor and drop
them both at the same time. Point out to students that the papers were identical, but that the flat paper took
longer to fall than the crumpled up paper. Ask students why this occurred. Lead students into the idea that it
was the shape of the flat paper that caused it to fall more slowly. Point out that it was the air under the paper
that made the paper fall more slowly. Ask the students what would happen if you could get rid of the air
under the paper. After they bring up several ideas, take the flat piece of paper and lay it on top of a book that
is at least the size of the paper. Ask the students what will happen if they are dropped together. (Most think
the paper will fly off the book and still fall slowly.) Drop the book with the paper on top of it. It will fall
quickly. Summarize by telling students that, if air resistance can be cancelled, all objects will fall at the same
rate (the acceleration due to gravity). Tell students that their lab will look at the acceleration due to gravity.
B. Instructional activities
(demonstrations, lectures, examples, hands-on experiences, role play, active learning experience, art, music, modeling, discussion, reading, listening, viewing, etc.)
Go over Transparency - vocabulary.
C. Guided activity or strategy
Demonstrate for students how to count the pendulum swings and have them practice several trials.
Demonstrate how to use a buret (or other container used) and allow them to practice how to get one drop to
fall at a time.
Students requiring modifications may be given a copy of the vocabulary definitions.
Students requiring enrichment may be assigned the definitions the previous night for homework.
II. STUDENT PERFORMANCE
Students should complete Lab Worksheet – Drip, Drop
Students requiring modifications should be assigned a peer tutor. The tutor may also help during the
calculation portion of the activity or students may receive additional help or leniency on grading the
Students requiring enrichment should act as peer tutors.
III. ASSESSMENT OF ACTIVITIES
Vocabulary may be assigned and taken as a grade or merely gone over in class.
Grade Lab Worksheet – Drip, Drop
B. Rubrics/grading criteria
Data table information may be graded as 4 points a box. Questions should be graded as 4 points each. Each
box or question incorrect or left unanswered should have up to 4 points deducted.
Students requiring modifications may be given additional help on the calculation phase of the activity. The
Critical Thinking and Application questions in the activity may be graded with leniency or not assigned for
students requiring modifications.
Students requiring enrichment should answer all questions.
E. Sample discussion questions
1. Why do objects fall? They are attracted to the center of the earth because of gravity.
2. Since the acceleration due to gravity on Earth is 9.8 m/sec2, how fast would an object be traveling after 1
second? 9.8 m/sec
3. How fast would be object be traveling after 2 seconds. 2(9.8 m/sec) = 19.6 m/sec
4. Will an object continue to accelerate forever? No, only until it reaches terminal velocity.
5. When will an object reach terminal velocity? When the downward force of gravity equals the upward force
of air resistance.
6. If 4 objects (a book, a penny, a feather and a piece of flat paper) were dropped from the same height in a
container that does not contain air, which will hit the floor first? None, without air, they will all fall at the
same rate and hit the floor at the same time.
7. If two objects of identical size and shape were dropped from the same height on Earth, the heavier one will
reach the ground first. Why? The heavier object will not reach terminal velocity as fast and will continue
IV. TAKS PREPARATION
A. Transition to TAKS context
1. During an investigation, students accelerated boxes using different forces and then determined the masses
of the boxes. What is the mass in grams of a box that requires 0.1 newton to make it accelerate 2 m/s?
(a) 50 g
(b) 20 g
(c) 0.05 g
(d) 0.02 g
2. A motorcycle accelerates from a speed of 5 m/s to 70 m/s in a total time of 4.4 seconds. What is the
(a) 12.5 m/s2
(b) 15.91 m/s2
(c) 1.25 m/s2
(d) 19.32 m/s2
B. Sample TAKS questions
1. A ball moving at 30 m/s has a momentum of 15 kg.m/s. The mass of the ball is ____.
(a) 45 kg
(b) 15 kg
(c) 2.0 kg
(d) 0.5 kg
2. How much work is performed when a 50 kg crate is pushed 15 m with a force of 20 N?
(a) 300 J
(b) 750 J
(c) 1,000 J
(d) 15,000 J
3. If a force of 100 newtons was exerted on an object and no work was done, the object must have ____.
(a) accelerated rapidly
(b) remained motionless
(c) decreased its velocity
(d) gained momentum
4. The weight lifter used a force of 980 N to raise the barbell over her head in 5.21 seconds. Approximately
how much work did she do in raising the barbell?
(a) 380 J
(b) 982 J
(c) 2,000 J
(d) 10,000 J
V. KEY VOCABULARY
air resistance terminal velocity
A. Textbook – none needed
B. Supplementary materials/equipment
Instructor’s Copy – Drip, Drop
Lab Worksheet – Drip, Drop
Transparency – Vocabulary
Instructor’s Copy Transparency - Vocabulary
Worksheet – Force = mass x gravity
Instructor’s Copy Worksheet – Force = mass x gravity
VII. FOLLOW UP ACTIVITIES
(reteaching, cross-curricular support, technology activities, next lesson in sequence, etc.)
Assign Worksheet – Force = mass x gravity.
Next lesson in sequence
All subjects continue with IPC 4B: investigate and describe applications of Newton’s laws such as in vehicle restraints, sports activities, geological processes, and satellite orbits.
VIII. TEACHER NOTES
1. Run enough copies of the Lab Worksheet – Drip, Drop and Worksheet – Force = mass x acceleration for each
student to have one.
2. Make a transparency of Transparency – Vocabulary.
3. Decide on whether to use burets or another container where drops can be regulated.
4. For more uniform answers on Part A, the pendulums could be pre-assembled with all of the lengths the same.
5. For more uniform answers on Part B, the burets could be pre-set at a certain height and students could be told not to
adjust the height.
5. Spot check to assure that students are counting the pendulum swings correctly.
6. Spot check to assure that students have the burets dripping properly.