Interactive Study Links:
• Debbie's Flashcards, etc. M4 (also see the list of objectives)
• Simple and Complex Machines - interactive, just for fun. =)
• Edheads: Simple Machines - interactive, just for fun. For simple machines, hover over the house.
• See the Inventor's Toolbox for examples of Simple Machines, then go to Gadget Anatomy to test what you learned.
• Edheads: Simple Machines
• Penny Lever lab, etc.
• Wheel and Axle
• A Screw is a kind of Inclined Plane (worksheet)
• Lever, Wheel and Axle, Pulley
• Six Simple Machines (I like the popcorn one on p. 5!)
• See these and more at Debbie's Educator's Resources (Thanks, Debbie!)
(1) p. 83-86a, The Distinction Between Science, Applied Science, and Technology
►Science attempts to understand how the universe and everything in it works, and how it is all interconnected.
Science is motivated by curiosity. The goal of science is knowledge.
►Applied science takes that knowledge and applies it to improve or simplify our lives. In other words, take the knowledge and do something useful with it.
The goal of applied science is to find a way to make something easier.
►Technology is the invention that makes things more simple or easier.
The goal of technology is to use the applied science to actually make a product that will make something more simple or easier.
Technology is not always a machine. Technology is "any invention or process that makes life better or a job easier." -Apologia General Science, p. 84
If you do an experiment and learn something from it, that is science.
If you find a way to make something better or easier, you have applied that science.
If you actually invent something to make life better or a job easier, that is technology.
(2) p. 86-92, Simple Machines; The Lever
Effort is the force used to push or pull.
Load or resistance is what is being lifted or pulled.
Fulcrum is the point at where there is a hinge-like motion.
►See this picture
►Read More about Simple Machines
►Understanding Simple Machines
►By using any simple machine to increase force or motion, you have an advantage called a mechanical advantage (or MA). This mechanical advantage can be measured.
Formula for finding the Mechanical Advantage of a Lever:
MA = (distance from fulcrum to effort) ÷ (distance from fulcrum to resistance/load)
We used the term "fe-fr" to help us remember the order.
If you look at the image of the three classes below, you will see it can take a bit of brain work to think how to apply this formula to each of these different levers.
1st class, 2nd class, and 3rd class levers
Remember FLE (or FRE):
F(orce) in the middle = 1st class
L(oad) or R(esistance) in the middle = 2nd class
E(ffort) in the middle = 3rd class
(3) p. 93-95, The Wheel and Axle
Formula for finding the Mechanical Advantage of the Wheel and Axle:
MA = (diameter of the wheel) ÷ (diameter of the axle)
(4) p. 95b-99, The Pulley
Formula for finding the Mechanical Advantage of Pulleys:
MA = count the number of pulleys! =)
Unless there is only one pulley -- then there is NO mechanical advantage because all you did was change the direction of the pull.
And that is why, on a 20-speed bicycle for example, you have to pedal faster than on a single-speed bike (with one gear). When the force exerted is easier, the distance will be greater. Your pedals have to move a greater distance. On a single-speed bicycle, you have to exert more force, but do not need to pedal as fast.
(5) p. 99b-100, The Inclined Plane
Formula for finding the Mechanical Advantage of an Inclined Plane:
MA = (length of the slope) ÷ (height)
(This is the same as the formula for the wedge)
(6) p. 100b-102a, The Wedge
Formula for finding the Mechanical Advantage of a Wedge:
MA = (length of the slope) ÷ (height)
(This is the same as the formula for the Inclined Plane)
I couldn't find any useful videos for the wedge. So if you
know of any, please let me know! =)
A wedge may look like an inclined plane, but it is used differently.
►"An inclined plane is meant to ease the force required to lift a load."
[Something moves over the surface of an inclined plane.]
►"A wedge... magnifies the force that is being applied." Apologia General Science, p. 101
[A wedge moves through something.]
Most common is the wedge used to split wood. This is a double wedge -- two wedges put together.
Sometimes splitting wood with an axe is not quite enough. A splitting wedge can be placed on the upended wood and a sledge hammer used to force the wedge into the wood.
Here is how one man used a tire to help him! Click over to about 3:00 minutes.
You girls may sometimes wear wedge shoes.
You might eat a wedge of cheese or a salad wedge.
If you want to sit between your two best friends, you can wedge in between them. This can be very useful, but I would not call it a simple machine. =)
(7) p. 102-105, The Screw
Formula for finding the Mechanical Advantage of a Screw:
First find the Circumference of the screwdriver or device turning the screw:
1. Circumference = 3.1416 x (diameter) [note: this is the only multiplication in the formulas in this module.]
Plug the circumference into your MA formula:
2. MA = (circumference) ÷ (pitch) "Pitch" is the distance between threads on the screw.