50 Agricultural Mechanics and Technology Systems
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work includes recording activities such as travel to worksites and developing
reports. An exploratory SAE typically does not require a student to invest
money in a project or take a fi nancial risk. Financial risk is the uncertainty of
receiving a return on money invested in a project.
Research
A research SAE is an original project that involves agriscience—the
application of scientifi c principles to an agricultural problem. In research
SAEs, students experiment or conduct an analysis in order to expand
knowledge about a certain topic. This type of SAE requires the student to
understand and apply the scientifi c method.
Research SAEs can be conducted using experimental or nonexperimental
methods. An experiment involves orderly procedures to test hypotheses
about how physical processes work under particular conditions, Figure 3-5.
Nonexperimental research is descriptive research performed by collecting
and comparing information. Nonexperimental research does not control
confounding variables and does not allow the research to assume
relationships between variables.
Science photo/Shutterstock.com
experiment. It is not changed by the
researcher, but is observed to determine
the effect of changes made to the
independent variable. An experiment
must also provide for adequate control
of confounding (external) variables that
could affect the interpretation of results.
If the hypothesis is not verified by
the results of the experiment, it may
be modified and again be tested by
experimentation. After experiments have
been carried out, the data is gathered and
analyzed. A conclusion is formed based
on the analysis of the data.
STEM STEM Connection Connection
The Scientifi c Method
The scientific method is a series of steps used to
answer questions and draw conclusions. The scientific
method can be used to answer scientific questions as well
as simple, everyday questions.
The following are the common steps of the scientific
method:
1. Ask a question.
2. Research to form a hypothesis.
3. Experiment.
4. Gather and analyze data.
5. Form a conclusion.
The first step in the scientific method is typically to
ask a question based on observation. The next step is to
do research to form a hypothesis. A hypothesis is your
prediction of the answer to your question. Once you have
formed a hypothesis, you design an experiment to test
whether the hypothesis is true.
Experiments are conducted by controlling certain
variables to determine the effect on others. Variables
are conditions or processes that affect the results of
the experiment. An independent variable is a condition
or process that is changed by the researcher. The
dependent variable is the variable being tested in the
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Battery-Operated Power Tools
Another common DC power source for a portable power tool is a
rechargeable battery. Battery-operated tools are also known as
cordless
power tools and commonly use between 9.6 volts–36 volts DC power. Tools
equipped with similar motors deliver higher speeds proportional to higher
voltage inputs. Conversely, as more torque is applied to a power tool, it uses
more amperage or current.
Three main types of rechargeable batteries are used in cordless power
tools. Nickel-cadmium (NiCad) batteries
are the oldest example. NiCad
batteries are the least expensive and last for about 1000 charge cycles, but
they can easily deteriorate when not charged and discharged properly.
Nickel-metal-hydride (NiMH) batteries
can run two to three times
longer on a single charge than NiCad batteries. NiMH batteries, however, are
very sensitive to improper charging methods and storage conditions. Deep
discharging will shorten their life span, and exposure to extreme high or low
temperatures degrades the battery.
Both NiMH and NiCad batteries can develop a
charge memory effect.
If
they are improperly charged, a charge memory develops in these batteries,
allowing only a portion of the battery to accept a charge.
Lithium-ion (Li-ion) batteries,
although more
expensive, outperform the other battery types used
in power tools,
Figure 8-2. Due to their high power
density, Li-ion batteries offer a more uniform delivery
of power. The performance of NiCad and NiMH
batteries starts slowing down at about 70% charge.
Li-ion-powered tools deliver uniform speed and torque
down to about 20% of a full charge. Li-ion batteries last
only for 350 to 500 charges, but they do not suffer from
a charge memory effect.
The key to preserving the life of power tool
batteries is using a quality charging system.
Battery
chargers use standard 120-volt AC current to fully
charge a battery in 1 to 16 hours. Fast charging is
not always best. NiCad and NiMH batteries last
longer using chargers that deliver a full charge in
about an hour, but Li-ion batteries can be damaged
by chargers that offer less than a 3-hour complete
charge time.
The run time on battery-operated tools varies greatly depending on the
energy demands placed on the tool. Tools for drilling or driving fasteners
may have a 30-minute battery life, while tools that are used for grinding
or sawing are often limited to a 15-minute run time or less before a fully
charged battery is needed. Contractors who rely heavily on battery-operated
tools address the limited run time by having multiple batteries and charging
stations set up on a job site.
Jeffrey B. Banke/Shutterstock.com
Figure 8-2. Manufacturers
of cordless power tools
may use a single lithium-ion battery designed to fit
multiple cordless tools within their product line.
Safety Note
Although many of today’s
portable power tools are
capable of safely using
AC or DC current, check
for an AC/DC rating
marked on the tool or
in the manufacturer’s
instructions—especially
with older tools—before
attempting to connect to
a direct current power
source. Injury or tool
damage could result
from connecting to an
unsuitable power supply.
Safety Note
The cadmium in NiCad
batteries is considered a
heavy metal that is highly
toxic to the environment
when disposed of
improperly.
10 Agricultural Mechanics and Technology Systems
Copyright Goodheart-Willcox Co., Inc.
Mathematics for Agricultural Mechanics
Mathematics, or math, involves the study of quantities, patterns,
shapes, and changes. Math is an essential tool in the fi eld of agriculture and
agricultural mechanics because it is critical for solving problems related to
equipment and technology. Agricultural scientists, engineers, and many
other agricultural professionals use math daily. Mathematical problem
solving requires the ability to use information and facts to arrive at a solution.
Diagrams and sketches, patterns, equations or formulas, and unit cancellation
are all ways to approach solving math problems.
Common math terms used in solving problems for agricultural
mechanics and technology include:
• Distance—the amount of space between two items; used to measure
length or displacement.
• Perimeter—a continuous line forming the boundary of a closed
geometric shape, such as a crop fi
eld.
• Area—the size of a surface, such as the total square footage of a piece
of land.
• Temperature—a measure of an object’s heat energy.
• Volume—the amount of space occupied in three dimensions.
• Weight—the force of gravity acting on a body.
•
Force—an action that causes motion or a change of motion.
• Pressure—an amount of force exerted over a given area.
• Velocity—the rate of movement of an object expressed as distance
over time.
SAE Connection SAE Connection
Supervised Agricultural
Experience (SAE) in
Agricultural Mechanics
Are you creative? Do you enjoy building things?
Would “working with your hands” be an item listed
on your resume? Do you like to figure things out?
If you answered yes to these questions, a career in
agricultural technology and mechanics may be right
for you. From John Deere’s beginnings with the steel
plow to the massive tractors used today, agricultural
mechanics is a foundational part of agriculture.
As an agriculture student, you will likely be
introduced to the concept of the supervised agricultural
experience (SAE) as a part of the agricultural education
curriculum. There are countless opportunities for you
to engage in agricultural mechanics SAE projects.
You may repair and maintain an engine or install
and troubleshoot precision components for tractors,
sprayers, spreaders, harvesters, and other equipment.
The most difficult part is deciding where to start! Good
luck, and remember to talk with your agriculture teacher
about the SAE possibilities in your area.
Goodheart-Willcox Publisher
28 Agricultural Mechanics and Technology Systems
Copyright Goodheart-Willcox Co., Inc.
• Detailed records of hours worked and skills performed each day.
• Samples of work products. For example, you might include a report on
the safety review you did for the local equipment dealer or a copy of
the presentation you gave to the school board on repairing the athletic
fi elds at your school.
It is also helpful to have teachers or employers write letters explaining
what you learned in specifi situations. These are somewhat different than
letters of recommendation in that they address the specifi c skill(s) you
learned during a particular project or span of time. These, too, should become
part of your portfolio..
Documentsstnem
Other, more traditional documents that are needed for securing a job
include a résumé, cover letter, and list of references. You will often need these
when fi lling out a job application, or sometimes an employer will ask for
after you have submitted an application.
A résumé is a summary of your experience, education, and skills. A
cover letter is a letter, usually no more than one page, that introduces a job
and refers the reader to the accompanying résumé. Employers
may also want to hear information from people who know the job applicant,
personally or professionally. These people are known as references. The
applicant must provide their names and contact A reference can
be a friend or family member, but employers usually prefer former teachers,
or supervisors..
These documents should be prepared as if were your only chance
of making a good because they often are. Spelling and grammar
cause many applicants to be rejected before their documents even
make it to the hiring personnel. Many students say, “I won’t be writing on
my job; they really don’t care if I have a résumé.” These students are wrong.
Agricultural Mechanics Teacher
Job description: Agricultural mechanics teachers teach introductory
and advanced courses in agricultural mechanics and technology.
Course topics include welding, power equipment, construction, and
computer technology. Agricultural mechanics teachers may also advise
the FFA chapter and actively participate in curriculum development.
Education required: Bachelor of Science in Agricultural Education
or closely related field with the expectation of acquiring a graduate
degree, such as a Master of Science or Master of Arts in Teaching.
Job fit: This job may be a fit for you if you enjoy helping people
and working with technology. Individuals who are problem solvers and
have natural curiosity about how things work will enjoy this career.
Career Connection Career Connection
auremar/Shutterstock.com
I t is also help ful to have teachers or emp loyers
what you learned in specifi c situations. The se are s fic
letters o f recommendation in that the y address oonly nl
learned durin g a particular pro ject or span o f t ime.
part of y our portfolio
Docu
O ther, more traditional documents that are nee
include a résumé, cover letter, and list of refe rences
when fi lling out a job application, or sometimes an fi
tthem hem after y ou have submitted an applicati on.
A résumé is a summary of your experience, ed é
cover letter is a letter , usua lly no more than o ne pa r
ccandidate andidate and ref ers the reader to the accompany in
may also want to hear inf ormation f rom peo ple wh
eeither ither personally or prof essionally. These peopl e ar
applicant must provide their names and contact iinformation. n
b e a friend or famil y member, but emplo yers usua l
cco-workers, o-wor kers, or sup ervisors
T hese documents should be prepared as if tthey hey
of mak ing a g ood iimpression, mpress ion, because the y often a
eerrors rrors cause many applicants to be rej ected befo re
ma ke it to t h e h iring personne l. Many students s ay
my job; they really don’t care i f I have a résum é.” T
26
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Continuing Education and
Training
Many students can enter the job market
with a basic set of skills, then improve their
skills with
continuing education . Generally,
this training is available from local technical
or trade schools, industry associations,
colleges or universities, or online schools.
Some employers offer tuition reimbursement
to their employees for continuing education.
It is wise to take advantage of the opportunity
to improve your skills through continuing
education, especially if the employer will
pay for the training.
Education Needed
Because of the wide variety of careers
available to skilled agricultural mechanics, the educational requirements
for each specifi
c job vary as well. Students can prepare directly for many
agricultural mechanics jobs in a high school training program, certifi cation
program, or apprenticeship. However, more opportunities are available if
the student has received an associate degree from a trade or technical school,
or from a community college. As the job responsibilities increase, students
may determine that the next logical step in their education is a bachelor’s
degree, which opens many doors at the engineering and technically skilled
AgEd Connection AgEd Connection
We spend much of our lives preparing for and
working in our careers. There are many career
opportunities in agriculture, and one of the best ways
to prepare for your job search is to participate in a job
interview CDE.
A job interview CDE will allow you to develop,
practice, and demonstrate the skills needed when
seeking employment in agricultural industry. In this
event, you may be required to create a cover letter and
résumé, complete an electronic job application, practice
telephone skills, and participate in a personal interview.
Awards may be available for winners, and everyone
who participates will gain valuable experience that will
help prepare them for actual job applications. Ask your
advisor and agriculture teacher about participating in a
job interview CDE today.
Job Interview CDE
racorn/Shutterstock.com
goodluz/Shutterstock.com
Figure 2-5.
The compensation you receive from an apprenticeship
may be wages, or it could be the knowledge and experience you
gain from the work.
x
Career
Connections
introduce careers
in different
agricultural areas
and can help
provide a path for
career success.
SAE Connections make real-life
connections to a variety of interesting
SAE opportunities.
AgEd Connection features introduce
you to the exciting world of leadership
and personal development opportunities
including career development events in
a variety of areas.
STEM Connections
integrate all four
components of STEM
education as well as
the social sciences
and language arts.
Safety Notes alert you to potentially
dangerous materials and practices.