MECHANICAL SYSTEMS:
Name: ________________________8___
Date: _________________________
LEARNING OUTCOME #2: Analyze machines by describing the structures and
functions of the overall system, the subsystems and the component parts
2b) identify the source of energy for some familiar mechanical devices
LEARNING OUTCOME #1: Illustrate the development of science and technology by
describing, comparing and interpreting mechanical devices that have been improved
over time
1a) investigate and provide examples of mechanical devices used in the past to
meet particular needs
1b) illustrate how a common need has been met in different ways over time
1c) illustrate how trial and error and scientific knowledge both play a role in
technological development (e.g., development of aircraft)
LEARNING OUTCOME 4; Analyze the social and environmental contexts of science and
technology, as they apply to the development of mechanical devices
4a) evaluate the design and function of a mechanical device in relation to its
efficiency and effectiveness, and identify its impacts on humans and the
environment
4c) develop and apply a set of criteria for evaluating a given mechanical device,
and defend those criteria in terms of relevance to social and environmental
needs
4d) illustrate how technological development is influenced by advances in
science, and by changes in society and the environment
READ PAGE 254-268 TO ANSWER THE FOLLOWING:
1. A machine is ___________________________________________________
2. What was a “sakia” (Persian Wheel)used for?
3. What did Archimedes invent that replaced the “sakia”?
4. What has been invented that replaced hand power to run this device?
5. A simple machine is _________________________________________________
______________________________________________________________________
6. What are the six simple machines?
1. __________________________________
2. __________________________________
3. __________________________________
4. __________________________________
5. __________________________________
6. __________________________________
REMEMBER FROM GRADE 7?
7) Force is defined as PUSH OR PULL ON AN OBJECT.
8) Force is measured using a _______________ __________________ (instrument).
9) A spring scale records force using ______________________________.
-look at a green spring scale: _______ grams equals 1 newton.
-if an object weighs 400 grams it would measure _____newtons.
10) A green spring (5N) scale can measure
__________N to _________N
a red spring (20N) scale can measure __________N to _________N
a white spring (30N) scale can measure __________N to _________N
11) You would use a _________ spring scale to measure an object that
weighs 50g, and a ____________ spring scale to measure an object that measures
650 grams. the 5N scale is most sensitive.
12) Using a second green scale how much does a spring scale weight?
____g or ___N
13) When a force is applied to an object to make it move or change
direction it is considered to be the input or effort force.
14) Each simple machine can give you either a
-______________________________________________ advantage,
(less input effort is needed to move a heavy object ie: 100N to move 5000N)
- _____________________________________________ advantage
(object moves a long distance compared to the distance the input force moves)
or
- a change of ____________________________.
(object goes in the opposite direction as the input force)
SIMPLE MACHINE: THE PULLEY!
A "pulley" is a simple machine that: _______________________________________________
__________________________________________________________________________________
PROCEED TO LAB A PULLEY SET-UP and answer the following:
1. Using the system set-up (identical to the one on the right. How
much effort force is needed to lift the object? ________N
Try changing the spring scale upside down, as shown to the
right? ________N
Since the block of wood is the same should the effort force be
the same? yes/no Is it? yes/no
Why/why not?
***when using a spring scale to pull downwards on something (handle over
the end), you must add the weight of the scale (0.5n) to your measurement
because the scale (weigh) is pulling down. example: if you’re scale
measures a downward force of 3.4 n, and the green scale weighed 0.5n the
actual force pulling down is 3.9n.
PROCEED TO LAB B PULLEY SET-UP and answer the following:
2. Using the fixed pulley system (shown to the right).
Predict how much effort force is needed to lift the object
__________N
Test the set up. Actual effort force needed to lift the object
is ______N
Explain any difference in the effort force needed from
LAB A set-up to this set up?
What advantage does a fixed pulley give you? _______________________
What are some examples of fixed pulleys that you see every day?
_____________________________________________________
PROCEED TO LAB C PULLEY SET-UP and answer the following:
3. Using the moveable pulley system (shown to the right).
Predict how much effort force is needed to lift the object.
_____________N
Test the set up. Actual effort force needed to lift the
object is ______N
Explain any difference you may have from LAB A, LAB B
to LAB C.
What advantage does a moveable pulley give you?
________________________________
What are some examples of moveable pulleys that you see every day?
__________________________________________________________________________
PROCEED TO LAB D PULLEY SET-UP and answer the following:
4. Using combination pulley system set
up at the front of the class.
Predict how much effort force is needed to
lift the object: ____________N.
Test the set up. Actual effort force needed to lift the object
is ______N
What advantage does a multiple or combination pulley give
you? ____________________________________________
What are some examples of combination pulleys that you see every day?
__________________________________________________
SIMPLE MACHINE: THE INCLINED PLANE
Name: ______________ 8__
1. An inclined plane is ______________________________________________________________
__________________________________________________________________________________
PROCEED TO LAB E THE INCLINE PLANE SET-UP and answer the following:
2. Using the inclined plane (ramp) set up (about
30 to the surface of your work table). Pull the
object the ramp.
How much force is needed to pull the load up?
__________N
What advantage does an inclined plane give
you? __________________________
What do you think would happen if you made the inclined plane longer thus getting
a smaller angle?
What do you think would happen if you made the inclined plane shorter and
steeper?
PROCEED TO LAB F THE INCLINE PLANE SET-UP and answer the following:
3. How is the incline changed from LAB E? steeper or shallower
How much force is needed to pull the object up the inclined plane? _________N
4. How can an inclined plane be used to decrease the effort force
required to move an object?
the further the horizontal distance you have to pull the load the
_________________________ effort force is needed to move a load.
or:
the longer the inclined plane the __________________________ effort force is
needed to move a load.
PULLY AND INCLINED PLANE REVIEW
1. What was the force of gravity on the load you lifted?
(hint how much effort was needed to lift the object?) _____________N
2. Which type of pulley, a fixed or moveable helped you lift the object with the least
effort?
3. Explain what happened as you increased the number of pulleys to your pulley
system in relationship to the effort force required.
the more pulleys used the _______________________ effort force is needed to
move a load.
or
the more rope you have to pull the _________________ force is needed to
move a load.
4. Did the inclined plane (ramp) reduce the effort force of moving the object, compared
to lifting it straight up? yes/no
5. One thing that has not been considered is friction. Friction occurs whenever two
surfaces rub against one another; therefore friction is the _________________________
to _____________________________ that creates ____________________________.
6. How does the following conditions effect the amount of friction?
Condition
effect on friction
(increase or decrease)
soft materials
large surface area
objects being moved
from a standing position
rough surface
high pressure between
surfaces (heavier objects)
7. Explain four conditions that would decrease friction.
effect on effort force
(increase or decrease)
An invention is a unique or novel device, method, composition or process. It may be an
improvement upon a machine or product, or a new process for creating an object or a
result. An invention that achieves a completely unique function or result may be a
radical breakthrough.
Technology: refers to the making, modification, usage, and knowledge of tools,
machines, techniques, crafts, systems, and methods of organization, in order to solve a
problem, improve a preexisting solution to a problem, achieve a goal, handle an applied
input/output relation or perform a specific function. It can also refer to the collection of
such tools, including machinery, modifications, arrangements and procedures.
Technologies significantly affect human as well as other animal species' ability to
control and adapt to their natural environments. The term can either be applied
generally or to specific areas: examples include construction technology, medical
technology, and information technology.
Since mankind has been on Earth there have been inventions. Think about all the
inventions that have been made and how technology has changed the world to what we
have today.
a) What do you think are the top TEN INVENTIONS EVER? List them in the
chart below!
b) Watch the video on inventions (H2) and record the number given to your idea
of the world’s best inventions ever!
#
1
Name of Invention
Ranking as H2
2
3
4
5
6
7
8
9
10
TOTAL POINTS:
How well did you do???
Were there items you did not even think of as an invention??
If yes, it shows how young you really are!! LOL
EVALUATING MACHINES:
Read page 304-308:
Do you think all the inventions you saw were perfect the first time? _____ Probably not!
They needed evaluation!
1. Mechanical devices are constantly evaluated to _______________ ways to
_______________ _________ so they can sell more.
2. Inventors evaluate devices to __________________________________________________ or
to find
__________________________________________________________________________.
3. Using the bike complete this chart:
Definition
Efficiency:
21-speed bike
One-speed bike
Mountain Bike
Road Racing
Effectiveness:
Function:
Design:
4. Cost and how the device affects the environment is another factor in evaluating
mechanical devices. How does the environment affect the design of a mountain bike?
5. Read figure 3.4 and explain the environmental concern.
EVALUATING A MECHANICAL DEVICE—A CASE STUDY (page 308-312)
DEVICE: pop can opener
Opener Design
Iron Can (late 1810)
Advantages
Non breakable
Steel Can (late 1850’s)
Have a metal zip opener
Disadvantages
Only opened with hammer
and chisel—heavy—rustsexcess iron in food
Heavy
Aluminum Can
1958
Church Key
Light weight
Need something to open it
Removable pull tab
Push button tab
Non-removable pull tab
Today aluminum cans are
replaced by plastic
(caps/pull up lids/etc.
The pop can openers have changed due to both human and environmental needs
along with new material, new technology and of course failure and trial and error.
TECHNOLOGY DEVELOPS THROUGH CHANGE (Page 315-319)
Sewing machines have changed over the years. Look at figure 3.14 on page 315.
Explain how and why the sewing machine changed from abc. Think about
technology, human wants and needs.
OH HOW THINGS HAVE CHANGED!
STORAGE OF INFORMATION FROM COMPUTERS
http://www.backuphistory.com/
FUNCTION: Store data from computers and transfer data to another computer.
PUNCH CARDS:
TAPES
FLOPPY DISCS
CD’s
USB
1951 punch cards can be
considered as the first data
storage devices for backup
1960-1980
1969 the first floppy disk was introduced
CD-Recordable (CD-R) and
CD-Rewritable (CD-RW)
drives. 1982
Portable USB storage flash
drives, invented in 1998
Design: paper with holes
punches as a code
Effectiveness: did the job
as long as the paper did
not get torn or damages
Efficiency: very slow and
low-capacity
Design: vinyl tape rolled
inside a plastic case
Effectiveness: recorded
material as a backup
Efficiency: very reliable,
held lots of information
Environmental Issues:
plastic and vinyl take a
long time to decompose.
Reusable so less use of
resources
Advantages: got the job
done
Disadvantages: slow, lowcapacity and required a
lot of devices, efforts and
time for processing, easily
damaged
Advantage: tape drive’s
reliability, scalability and
low cost
Disadvantage: tape could
be damaged easily
Design: thick,
polycarbonate plastic
disc, smaller
Effectiveness: backs
up data
Efficiency: very easy
to store, transport
and restore data
Environmental
Issues: plastic and
vinyl take a long time
to decompose.
Reusable so less use
of resources
Advantages: stores
more data than floppy
discs, easy to use and
has a longer life span
Disadvantage: high
costs to start with,
then fell, disc could
be scratched or
corrupted easily
Design: hard outer plastic
shell, inside is a small
printed circuit board
Effectiveness: stores data
Efficiency: small, easy to
use and transport data
Environmental Issues:
natural, decomposes but
uses lots of paper
Design: soft or hard rectangular
shell with a recording disc
inside.
Effectiveness: backed up data as
read-only. In 1973, a similar
floppy disk was rewritable.
Efficiency: easy to use, quick,
smaller and holds more data
Environmental Issues: plastic
and vinyl take a long time to
decompose. Reusable so less
use of resources
Advantage: stores more data
than tapes, being much cheaper
and more flexible
Disadvantage: still relatively low
capacity, disc only lasts a few
years, easily corrupted
Environmental Issues:
plastic and vinyl take a
long time to decompose.
Reusable so less use of
resources but easy to lose
Advantage: small, stores
several times more data
than a traditional 3,5 inch
floppy disk, and larger
ones can hold as much
data as a CD-ROM or even
more
size, power and costeffectiveness of these
drives longer lifespan
Disadvantage: easy to lose
The science of vinyl caused the change, along with the technology of applying the use of
Technology of plastics improved the size and
vinyl to data storage. Humans wanted easier ways to store data and to be able to restore
storage ability along with the ability to be reusable
data easily. Improvement allowed more data to be stored.
and lower chances of corruption.
Future: In the future I see the USB key being even smaller and would have the ability to record and/or restore data remotely. No more USB
ports needed. The amount of data to be stored would be greatly increased with small device size.