Simple Machines
Why do boats have all these ropes and pulleys?
Module 4: Chapters 2-4
Grade Level
Middle School
Subject Areas
Physical Science, Boat Rigging,
Knots
Duration
Preparation time: 20 minutes
Lesson Time: 1 hour 40
minutes
Part I: 10 minutes
Part II: 30 minutes
Part III: 30 minutes
Part IV: 60 minutes
Setting
Indoor/Outdoor/On the water
Skills
Vocabulary
Block, halyard, pulley,
compound pulley, fixed
pulley, movable pulley,
simple machines, inclined
plane, screw, wedge, wheel
and axle, lever, force, work,
load.
Summary
Background Knowledge
Students identify and explore the six
simple machines. They will identify
compound, fixed, and moveable
pulleys on the sailboat and test the
benefits of 1:1 vs. 3:1 purchase
systems.
Simple Machines are used on sailboats to
reduce the amount of work needed by the
sailor and help us move things. There are
six simple machines; the most common
simple machine found on a sailboat is a
pulley. Sailors call pulleys blocks.
Objectives
Students will:
 Describe the six simple
machines and their application
to the sport of sailing.
 Identify the difference
between fixed and movable
pulleys.
 Create compound pulleys
 Apply the mechanical
advantage of a pulley when
raising and or trimming sail.
 Understand the net effect of
multiple forces on the position,
speed, and direction of the
motion of a sailboat.
Materials
 Learn sailing Right! Beginner
Chapters 2-4.
 Student Sheet Module 3:1
Scavenger Hunt Sheets (1 per
group)
 Student Sheet Module 3:2
Rigging (1 per person)
 One de-rigged instructional
boat.
 One de-rigged boat per group
for pulley (block) identification,
rigging and sailing
 Clipboards (1 per group)
Procedure
Part I (Outdoor Classroom)
10 minutes
Pre-reading: Assign Chapters 2-4 in Learn
Sailing Right! Beginner before today’s class
(not imperative).
1. Before teaching students how to rig a
sailboat, take the students out to the
boatyard. Have students gather around an
unrigged sailboat. Tell students that
sailboats can have very simple or very
complex rigging, but they all use the same
concepts. You have already learned how
sailboats are powered by wind, now we
are going to learn how to harness the wind
by maximizing the mechanical advantage
available to us.
2. Ask students to name a few parts of the
boat. (Bow, Stern, Port, Starboard) Remind
students that sometimes sailors use a
nomenclature or vocabulary.
3. Ask students, “What is this?” (point to a
pulley) “Does any one know what sailors
call these?” (Blocks) “Do you see any other
pulleys on the boat? Where?” Ask
students, Why do sailboats have so
many pulleys? What job does a
pulley do?”
3. Tell students today we are going
to learn how sailors decrease their
work by using simple machines.
4. Ask students to identify areas of
the sailboat where hard work is
being done. (Raising sails, trimming
sails, steering). Ask students how
simple machines are used to
reduce the amount of work.
5. This is a great time to teach
students how to rig a boat using
simple machines to reduce the
amount of work. Show students
the pulley in the top of the mast
that helps raise the main sail.
Explain each pulley as you rig.
Part II (Outdoors or Indoors)
Simple Machine Scavenger Hunt
30 minutes
1. Review the six simple machines
this can be done by a teacher in
class prior to the day at the sailing
center.
Pulley: Flag pole,
Screw: jar lid
Wheel and Axel: Car
Wedge: door stoppers
Inclined Plane: ladder, ramp
Lever: stapler
and scavenger hunt list.
3. Modification: Assign groups
certain areas; classroom, boatyard,
or boathouse.
4. After the scavenger hunt, gather
all of the students and review their
findings. Put the top 3 answers for
each simple machine on the board.
Suggestion: have teams switch
papers and check off the answers
as they are given. Give the winning
team some sort of prize or benefit.
Part III (Classroom/ Outdoor)
30 minutes
Identifying load and effort
Sailboats have a lot of pulleys.
Today we are going to discuss
fixed, moveable, and compound
pulleys. Pulleys are used to reduce
the amount of work. Using the
diagram of a sailboat identify the
load (sail), effort (person raising
the sail) and pulley type and
location. Explain that moveable
pulleys are usually used with fixed
pulleys and we refer to this
arrangement as a compound pulley
system. Fixed Pulleys: top of a
boat mast, jib pulley.
Moveable Pulleys: (find an
example of a moveable pulley)
1. Have students work in groups of
two or three per boat to rig a boat
and identify the pulley types on
board, the load, and the direction
of applied force.
2. Using a blank sheet of paper
2. Give students 30 minutes to find have students sketch the rig they
as many simple machines on the
are using, labeling each pulley
system on board.
property as possible. Students
should work in groups of 3 or 4.
Give each group a clipboard, pencil,
3. When students have completed
rigging their boats and identified
the pulley types on the boats,
students can either de-rig or
launch.
Part IV (On the water)
60 minutes
1. Ask students to identify the load on
the main sheet block. Ask students if
this load (pressure on the sail) ever
changes? How and when does it
change? Explain to students that the
load in this case is the amount of
pressure on the sail caused by the
wind and the point of sail. Sailors
reduce the amount of work needed in
windy conditions by modifying the
purchase system which is a compound
pulley.
2. While sailing ask students to tack or
gybe by grabbing the top of the
purchase and changing the sail
without using the purchase. Then, ask
them to tack using the purchase and
ask the about the difference.
3. Have a race with 1:1 purchase boats
vs 3:1 purchase or more. Does one sail
faster than the other? Does one sailor
need to exhort more effort (work)
than the other? Which point of sail
requires the most work from the
skipper? Why?
Resources:
1. NEOK-12 –games for kids on the
six simple machines
2. Minhsacademy – Video from Bill
Nye the Science Guy on Simple
Machines
Student Sheet Module 3.1
Group Names: __________________________________________________
Simple Machines
List Examples
1. Pulley
1.
2.
3.
2. Screw
1.
2.
3.
3. Wheel and Axle
1.
2.
3.
4. Wedge
1.
2.
3.
5. Inclined Plane
1.
2.
3.
6. Lever
1.
2.
3.
Student Sheet Module 3.2
Name: ________________________
Date: _________________________
Challenge: First, sketch your sailboat and the location of the pulleys used aboard. Second, label the pulley as
fixed, moveable, or compound. Last, label the load and direction of the applied force.