Welcome

If you would like to read the syllabus for the Life Science or Earth Science, please click on the links to access information such as classroom rules, the grading scale, and topics to be discussed.
One last thing that you might find interesting is a NASA picture of the day. Every picture has a great description of what you are seeing.


Enjoy!

Classroom expectations

I expect you to:

1. Always think safety first. NO HORESEPLAY IN THE LAB AREA!
2. Be in the room and prepared for class when the period begins.
3. Do your own work and work on science in science class.
4. Respect each other, yourself, and science as a worthwhile subject.
5. Follow all school rules including the dress code.
6. Take responsibility for your own actions!

I will not tolerate:
1. Swearing, offensive language, or rudeness
2. Tardiness
3. Cell phones in the classroom
4. Cheating
5. Physical Contact – hitting, kicking, pushing, etc.
6. Unsafe Actions – anything that you intentionally do that puts you or someone else in danger
7. Defiance

Sunday, March 18, 2012

8th Grade Chapter 20: Work and Simple Machines




Section 1: Work and Power quiz
Work (in joules) = force (in newtons) x distance (in meters)

Power (in watts) = work (in joules) / time (in seconds)

Section 2: Using Machines quiz

Mechanical advantage = output force (in newtons) / input force (in newtons)


Efficiency (in percent) = (output work (in joules) / input work (in joules)) x 100

Section 3: Simple Machines quiz

an inclined plane (uses less force over a longer distance)

Here is a description of an inclined plane (made by the text book)
A wedge and screw are examples of inclined planes

a lever allows you to mainly increase  output force (the trade-off is that you need to use less force over a greater distance)






Mechanical advantage = input distance / output distance

Here are 3 classes of levers
http://www.pearsonsuccessnet.com/ebook/products/0-13-181251-3/sx6104a3.gif

http://01.edu-cdn.com/files/89501_89600/89547/file_89547.jpg
Another example of a lever called a wheel and axle.  The wheel and axle is two circular objects that rotate together.  The larger object is the wheel and the smaller object is the axle.

The mechanical advantage = wheel's radius / axle's radius




A fixed pulley is a rope or wheel that is used to change the direction of force.

A movable pulley allows you to use a smaller amount of force over a longer distance. (this gives you a mechanical advantage)


Here is the Standardized Practice Test (this is primarily a math quiz doing calculations related to mechanical advantage, work, power, etc)
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