1. Part 2 Sections: Review The Wheel and Axle The Pulley and Block
Exploring Creation with General Science Week 9 - Mod 4 Science, Applied Science, and Technology
Part 2
Sections:
Review
The Wheel and Axle
The Pulley and Block
The Inclined Plane
The Wedge
The Screw
Next Time

2. Review page 1
What is Applied Science? (Not an example)_______________ What is Science defined? _____________________________ Which one is motivated by curiosity? _____________________ The difference between a double blind study and a blind study is _________________________________________________ What is a direct variable: _______________________________ What is an indirect variable: ____________________________ An example of Science is ______________________________ An example of Applied Science is _______________________ Studying cloud formations is ____________________________ I do an experiment to find a better gasoline, that’s _S__AS__T_ What is a vacuum tube? ______________________________ What is your favorite color? ____________________________ 2 2 2 2

3. Review page 2
In the OYO question about scuff marks, the cleaner was a ____________ variable. Why? Surface tension is ___________________________________. The 4 parts of the Scientific Method is 1. O__________ 2. H___________ 3. E____________ 4. T_____________ Technology is ___________________________________ I invented an electric car that goes for 200 mi. before needing a charge, that’s ______________ I create a book on the eating habits of mice - ______________ What is a “control” in an experiment: _____________________ Pliers are an example of a ______ ______ lever. A wheelbarrow is an example of a ______ ______ lever. Your forearm is an example of a _______ _______ lever. 3 3 3

4. The Wheel and Axle
Defined: a large circular wheel attached to a smaller cylinder typically a solid tube. As axle turns, so does the wheel. If both don’t turn together, it’s not a wheel and axle. Discuss Figure 4.4 4 4

5. The Wheel and Axle
Axle & wheel applications – 2 of them, both found in automobiles. 1st application: applied force from the engine (to transmission to drive shaft) to the axle causes the wheels to turn. 2nd application: a force (the driver) turns the steering wheel, it turns the steering column axle & car turns (many gears involved). 5 5

6. The Wheel and Axle
A wheel and axle offer us a mechanical advantage (M. A.). Calculate the M. A. by using the diameter of the wheel and the diameter of the axle. Diameter: the length from one point of the wheel to a point directly across from the first point. 6 6 6

7. The Wheel and Axle
Calculating the M.A. of the wheel: M. A. = diameter of wheel / diameter of axle. Similar, but different than the M. A. learned about in previous section. Often you can calculate the same thing for different situations, but the equations are slightly different. 7 7 7

8. The Wheel and Axle
M. A. for a wheel and axle depends on which way you use the combination. If you turn the wheel to turn the axle, the M. A. magnifies the force you are applying – if M. A. is 10 and you turn the wheel, the axle turns with a force 10 times as large. 18-wheeler steering wheel… 8 8 8

9. The Wheel and Axle
If you turn the axle to move the wheel, your force is not magnified. You have to turn the axle with a much greater force than the wheel will turn. But you will gain speed and the wheel will turn faster than the axle. Example: 10 speed bike – changing gears to gain speed. 9 9 9

10. The Wheel and Axle
Discuss Example 4.2 – wheel with a diameter of 24”. What does this M. A. mean? If you are turning the wheel, the force with which you turn will be magnified by 12. So the axle will turn with 12x the force that is applied to the wheel. 10 10 10

11. The Wheel and Axle
If you are turning the axle, the speed will be magnified by 12. Thus, the wheel will turn with a speed 12 times faster than that of the axle. On Your Own 4.6 11 11 11

12. The Pulley and the Block
The pulley consists of a grooved wheel that rotates freely on an axle attached to a frame, also known as a block. Simple device: pull down on the rope that goes through the pulley and is attached to the load at the other end and the load rises. Equal and opposite actions. Discuss Figure 4.5 12 12

13. The Pulley and the Block
A single pulley is useful when lifting heavy loads. Since pulling down on a rope (changing the direction of the force) is most often easier than lifting a difficult object, a person can move a big and heavy object. A single pulley offers no M. A. 13 13 13

14. The Pulley and the Block
Do the following… Experiment 4.2 A Simulation of a Series of Pulleys 14 14 14

15. The Pulley and the Block
What did you learn? Rope looped around handles once, difficult to move helpers. Looped around 3 times, got easier. More loops, the easier it is. This simulated the use of pulleys. 15

16. The Pulley and the Block
1st trial: simulation of single pulley. Pull rope, direction reversed, no M. A. Your force equaled their resistance. 2nd trial: looped rope around 3 times equaled to 3 pulleys. Gained a M.A. this time. Should have been much easier to pull people together. M. A. equaled 3 – using 3 pulleys. 16 16 16

17. The Pulley and the Block
Using multiple pulleys is called a BLOCK and TACKLE. One pulley is fixed, other is movable. More pulleys, more M. A. In all 3 types of simple machines, a M. A. is attained; it is used to multiply force. You get something good (you’re Superman and you can move an object), but what do you give up? 17 17 17

18. The Pulley and the Block
If you use a simple machine to magnify force, you have to use your force over a longer distance. With a lever closer to the fulcrum than the resistance, you have to push the lever farther than the load will move. Or if you’re using a wheel & axle, may have to use more force to gain speed. 18 18 18

19. The Pulley and the Block
SO… your force or effort is your payment for using the simple machine. If you magnify force, have to apply that force over a much longer distance. If you magnify speed, have to apply a much larger force. On Your Own 4.7 19 19 19

20. The Inclined Plane
The simplest of the simple machines. Allows you to lift heavy loads by sliding them up an incline or ramp. Don’t have to lift the load, so you can move something heavier than normal. Figure 4.6 for example of Inclined Plane. M. A. = length of slope / height On Your Own 4.8 20 20

21. The Wedge
The Wedge is different than Inclined Plane – see figure 4.7 Since these are used differently, they are considered different simple machines. Splitting wood example Double Wedge – figure 4.8 M. A. = length of slope/height On Your Own 4.9 21 21 21

22. The Screw
Last simple machine is actually an Inclined Plane wrapped around the middle of a Wheel and Axle. Figure 4.9 Length – pitch – threads – circumference Pi – geometry – typical pitch Calculations… 22 22 22

23. The Screw
Using your fingers to install the screw. Better to use a screw driver… one with a larger diameter than the screw. The fatter the screw driver, the more the M. A. you get. But if the blade doesn’t fit into the slot, no M. A. Discuss Example 4.3 On Your Own 4.10 23 23 23

24. For Next Time
Turn in your Lab Write-up for… Experiment 4.2 – “A Simulation of a Series of Pulleys”. Exp. 4.1 is not required. Turn in all “On Your Own” – 4.1 thru 4.10 Take test for Module 4 and turn in. Start reading Module 5. If you get half way through, that’s good. 24 24