Science.7
CLASS SET – Do Not
Work and the Human Body Lab
Essential Questions
1. What is the relationship between force and
motion?
2. What does it look like when we do work?
Write On This!
Vocabulary
Objectives
work, force, energy, Newton, joule
1. Explain and investigate work, energy and
force.
2. Contrast situations where work is done with
different amounts of force to situations where
no work is done.
Problem/Purpose: To investigate the scientific definition of work.
Background information: WORK is done when a force causes an object to move in the
direction of the force. For work to be done, two things must occur. First, you must apply a
force to an object. Second, the object must move in the same direction as the force you
apply. If there is no motion, there is no work. This is very different from the way we use the
word work in everyday life. Work can be calculated with this formula:
Work = Force X Distance
W=Fd
UNITS OF MEASUREMENT:
Force: Newtons
Distance: Meters
Work: Joules (NewtonsMeters)
Materials:
4 books
Ramp
Meter stick
Spring scale
PART 1:OBSERVINGWORK
Procedure:
1. Stand and hold your arms out in front of you at waist level, palms up.
2. Have your partner stack two books on your hands, one on each hand.
3. Lift the books to about shoulder level, then lower them.
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4. Now try raising them overhead. When your hands are overhead, are you working
harder than when you raised them to shoulder level?
Describe your observations in your ISN, using complete sentences
5. Lower the books again. Have your partner put two more books on each of your
hands, so you’re holding four books. Try to raise them to shoulder level. Are you
pushing harder (using more force) than when you were holding only two books?
Describe your observations in your ISN, using complete sentences
6. Hold the four books at shoulder level until your arms get tired. Are you exerting
force? Do you think you are doing work in these situations? What is the work
being done on?
Describe your observations in your ISN, using complete sentences
Have your teacher check your answers please.
Lab Modified from: M. Poarch – 2003
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Science.7
Work and the Human Body Lab
Name ___________________________
Date ____________________________
PART 2:
UNITS OF MEASUREMENT:
Force: Newtons
Distance: Meters
Work: Joules (NewtonsMeters)
Materials:
4 books
Ramp
String
Spring scale
Meter stick
Question: What affect will the steepness of a ramp have on work?
Hypothesis:
Independent Variable:
Dependent Variable:
Controls:
Procedure:
1. Set up the provided ramp flat on the table top. Loop the string around a book, and
hook this to the spring scale. Slowly and evenly, drag the book down the ramp. Try to
keep the measurement of force on the spring scale steady. Record the amount of force
used in the data table.
2. Use the ruler to measure how tall the ramp is (it is the height of the ramp itself),
record this in the data table. Careful to record this in METERS. (remember 100 cm = 1m)
3. Find out how much work you did by using the formula: work = force x distance.
Record your answer on your data table.
4. Repeat steps 1-3, but add one textbook each time to the end of the ramp, to increase
the incline of the ramp.
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Data Table:
Calculations of Work (Work = Force x Distance or W = F x D)
Object
Force (N)
Height of Ramp (m)
Work (J)
Flat =
Textbook
1 textbook =
Textbook
2 textbooks =
Textbook
3 textbooks =
Textbook
Conclude and Apply
1. As the ramp was made steeper, what happened to the force required to pull the book up? How did
this affect the work?
2. Was your hypothesis accepted or rejected?
3. A boy lifts a 30N desk 2 meters above the ground. How much work did the boy do on the desk?
Show your work.
4. Suppose you want to calculate how much work it takes to lift a 160 N barbell. Besides the mass of
the barbell, what other information do you need to know?
5. A 45N girl sits on a 8N bench. How much work is done on the bench? Show your work.
6. CHALLENGE: Identify 3 body systems directly involved doing the kind of work we did in this lab.
Explain how each was involved.
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