Cone Cylinder and Sphere Lesson Idea
\begin{eqnarray*}
V_{cylinder} &=& A \times H = \pi R^2H \\
V_{cone} &=& \frac 13 A \times H =\frac 13 \pi R^2H \\
\end{eqnarray*}
A cone with the same base area as a cylinder has a third
of the volume of the cylinder when both have the same height. To fill the
cyclinder to the brim or top using the cone, one has the fill the cone
three times. That can verified in a class. If the height of the cylinder
and cone equals the diameter. radius R of the cyclinder, then students
may verify that the volume of a solid hemisphere of diameter D = 2R plus
the volume of the cone equals the volume or capacity of the cylinder.
Here it may easier to take a solid ball, cut it in two hemispheres
and use its diameter D to provide the inner dimensions of the cone and
cylinder. Place the hemisphere in the cyclinder. Then take a cone
filled to its brim with water and pour its contents on top of the
hemi-sphere in the cylinder. The water should reach the top of the
cylinder and hemisphere. One could do a similar activity with a sphere in
place of a hemi-sphere if the H = D and not 2R, but water poured on top
the sphere tightly fitted in the cyclinder would not reach the space
underneath the sphere in the cyclinder because its path is blocked by the
sphere - Workaround: put half the water in first.
\[
V_{cylinder} +
V_{cone} = V_{sphere}
\]
Physical Verification of Formulas: The calculation of volume or
capacity from the product of base area times height can checked or
tested in the mathematics or physical science. The foregoing shows
how formula for the volume of a sphere can be related to formulas of
volumes of cylinders and cones. Prior to testing formulas for
volumes, we may test formulas for area calculations for circles or
disks: For example, take a piece of paper or carboard with with a
constant thickness and area per square unit (centimeter or inch) and
verify that the weight or mass of a disk of radius R of the material is
pR2 times the weight of a square
unit.
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Teachers & Tutors: Site pages offer better or best practices for providing skills -
simpler than expected & comprehensive but for exercises. For your charges, your duty is to study them alone or in
groups and develop skill building exercises & activities to share. Start now. The effort here is the best I can do.
Others are welcome to refine or exceed it. Please do.
Secondary
Mathematics for Ages 11+, A Practical Approach for home-tutoring or -schooling, or for schools & colleges
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into present or future lesson plans - some reading required.
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See too, the BBC-Belgium story Texting and
Driving - texting & the impossible test - the article links to a gruesome utube video on the subject
The Logic of Injustice:
How Texas sent
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justice, guilt beyond a reasonable doubt goes unrespected due to prosecutors who putting winning
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by asserting a pardon individual is still under suspicion. Then the pardoned individual or the latter's estate
is not compensation for years or decade
of improper or false imprisonment, or for execution. Site chapters on Logic
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May 2012, Composition Starting:
Pre-School and Primary Mathematics - Quantitative Skills, An
Intellectual View, Feedback Welcome:
The 8 Most Popular Site Inlinks
Parent Center: Help your child or teen
learn:
Parent-friendly
Work Booklets for ages 3+ to 13 Use these or others to check
or build skills. Other booklets are available but these booklets
allow parents unsure of themselves in mathematics to help their
children. The selection acquired in Canada is published in the
USA. So it has a US orientation. In retrospect, the selection
shows parents what to check with the booklets or by other ways,
the choice is theirs. But in retrospect, the selection does not
cover integral and fractions liquid weights and measures - ask
the publishers to correct that! For ages 9 to 12 say, parents may
compensate by showing boys and girls how to use weights or mass,
and further measures in food preparation. Beyond that children
may be shown how to measure and calculate angles, lengths and
areas [proportional amounts too] directly or by using maps and
plans drawns to scale. Learning how to gather and measure all the
ingredients, pots and pans for a dish or a meal, along with
cleaning up sets the stage for like activities or experiments in
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gives boys and girls a head start. Good luck. At the other
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McCainian: drill, drill, drill then Toronto
mathematician and actor John Mighton's jump math organization has jump math
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Fractions for
Grades 3-4 & Grades 5-6 [Read] Free Resources grades 1 to 8
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Mathematics
Skills For Ages 3 to 14 - technical!
Skills with take
home value - A few ideas
Basic skills include
time-date-calendar Matters; money matters; map, plan and
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Is your child able to add, subtract and multiply amounts
of money, work with fractions, work with clocks and calendars,
work with maps and plans, and measure length, weight-mass and
volume? Schools may promote your son or daughter without
providing basic skills in reading, writing and
arithmetic.
Arithmetic
and Number Theory Skills
Algebra
Starter Lessons
Geometry
- maps plans trigonometry vectors
More
Algebra
70
Calculus Starter Lessons
Calculus Lessons Elsewhere:
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How to Ace Calculus: Street Wise Guide - Mostly
Text.
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Flash
Video for Calculus Phobics
They cover basic topics in ways likely to complement your
notes, your textbooks and site material. When Goldilocks
trespassed in the house of the three bears, she found three bowls
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bears have different tastes. As invited guest here and elsewhere,
if one or more explanations is not to liking, try another. It may
be better or just right.
Unsolicited Advice
Learning to do and high marks if it comes to easy is often
deceptive - light rather than deep. For that reason, students
with learning difficulties determined not to let it get in their
way may go deeper and farther than those with none. High marks,
if the come easy, may be deceptive - provide a too light and not
a deep mastery. That could have been your problem in secondary
school, one that leads to comprehension shock or difficulties in
calculus and more generally in the first year of college. Bon
Appetite.
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