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Electric Forces Hold the Pieces Together

Electric Forces Hold the Pieces Together. This is Dr. Patrick Particulate. As you can see, he takes his job VERY seriously. You could say that he’s very particular about particles.

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Electric Forces Hold the Pieces Together

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  1. Electric Forces Hold the Pieces Together This is Dr. Patrick Particulate. As you can see, he takes his job VERY seriously. You could say that he’s very particular about particles. Since he’s so busy, we are going to save him some trouble and use an Instant Messenger program to talk with him. That way he can multi-task. Good thing he LOVES teaching! SOURCE: http://www.aip.org/history/electron/images/thoma3.jpg

  2. Please wait… Loading SciMaster Instant Messenger 2.1.0 program… Program Initializing…

  3. Class: Hello Dr. Particulate. This is the Science Class. Class: Are you there? Dr. P: Oh yes, Dr. Particulate at your service! Now then, I believe you are inquiring as to the nature of particles, is that correct? Class: Yes sir, Dr. P! Can you help us out? Dr. P: You bet your cathodes I can! It would be my pleasure. Dr. P: Here, let me upload a graphic that represents a particle of matter. Then I’ll tell you more about it. Dr. P: You just interrupt me if you have questions, okay? Class:Sounds great! Thanks! We’re all ears! (or eyes) lol Are you there? Sounds great! Thanks! We’re all ears! (or eyes) lol Hello Dr. Particulate. This is the Science Class. Yes sir, Dr. P! Can you help us out?

  4. Active-Edit graphic uploading from user Dr. P. . . Dr. P: Here is a picture that I will use to represent a particle. I can edit the picture while we are chatting. Dr. P: It is important to know that basic material particles are more than what they might appear in this picture. Dr. P: They are actually made up of even smaller parts, which act differently from each other. We call one major difference “charge,” and we say that some charges are “positively charged” and some are “negatively charged.”

  5. Class: Wait… why isn’t this one moving? The others were! Dr. P: Very good observation! =) You are absolutely right—this particle SHOULD be moving. However, I have made it look like it is standing still for now. I will correct this later. Excellent! Class: Thanks! We THOUGHT they should be… ;) Wait… why isn’t this one moving? The others were! Thanks! We THOUGHT they should be… ;)

  6. Dr. P: Any more questions? Class: Nope! This is interesting!  Dr. P: Well excellent! Alright then, back to charges. Dr. P: So we can use a + symbol for the positive charges and a – symbol for the negative charges. Does that make sense to you? Class: Sure does—positive is like adding something and negative is like subtracting something (+ and -). Nope! This is interesting!  Sure does—positive is like adding something and negative is like subtracting something (+ and -).

  7. Dr. P: Good, that works. Just remember that we are not actually adding or subtracting—the particles are made from smaller pieces of matter. Some are positively charged. Some are also negatively charged. Class: Right…got it. Positive and negative charges. Dr. P: Exactly.Here, let me add these to the graphic… Dr. P: Can you see them? Not a perfect picture, but it should give you the idea. Right…got it. Positive and negative charges.

  8. Class: We see ‘em. Look good to us. Class: So what exactly do these charges DO? Dr. P: Well, these particles are always in groups. Dr. P: Something about charges is that “opposites attract” and “same-sign charges repel.” Ever heard of this idea? Class: Kinda... So let’s see if we got this right… Class: If two +’s are near each other, then they will push apart. Same with two –’s. Right? We see ‘em. Look good to us. Kinda… So let’s see if we got this right… So what exactly do these charges DO? If two +’s are near each other, then they will push apart. Same with two –’s. Right?

  9. Dr. P: That’s right! They push each other away. When you have a + and a – near each other, they pull each other together. These pushes and pulls are called Forces. Dr. P: In fact, they are Electric Forces. When these Electric Forces are applied all over the place, it’s like having imaginary springs between each particle and its neighbors. Class: Springs? But…not REAL springs, right? Dr. P: Right. We just pretend they are there. Springs? But…not REAL springs, right?

  10. Dr. P: Here, let me show you what I mean… Dr. P: Bringing two particles near each other has an interesting effect. Dr. P: As you can see, the negative charges and the positive charges tend to move on opposite sides from each other. Class: Wait, is this because of the whole “opposites attract” thing?! Dr. P: You’ve got it! Yes! Wait, is this because of the whole “opposites attract” thing?!

  11. Dr. P: Do you need to see the process again? Class: Sure. Want to be sure we didn’t miss anything. Dr. P: No problem. Here you go. Dr. P: How was that? Satisfied? Was it clear enough? Class: We’ve got it this time. Thanks, Doc.  Dr. P: Of course. My pleasure! Dr. P: So let’s look at a simpler way of studying these charges…and how electric forces act like springs. Sure. Want to be sure we didn’t miss anything. We’ve got it this time. Thanks, Doc. 

  12. Dr. P: What could you say about the particles, now? Class: Uhm…well, I guess we could say that each one has a more positive side and also a more negative side? Dr. P: Wow, you got that one right off the bat! Excellent. Let me draw in some dotted lines to emphasize this. Dr. P: It’s okay, then, for us to replace these charges with signs that show the positive and negative SIDES. This will make our model a lot less cluttered. Uhm…well, I guess we could say that each one has a more positive side and also a more negative side?

  13. Class: That definitely makes this a LOT simpler. Dr. P: And that’s the purpose of modeling: to make complex things simpler. Dr. P: You probably already know that a force is a “push” or a “pull,” depending on the situation. Dr. P: Since we are working with charges, we say that the forces involved are electric forces, as I said before. Dr. P: It would be nice if we could visualize these forces. That definitely makes this a LOT simpler.

  14. Dr. P: Since forces are not physical objects, we can just draw them in as arrows. The direction of the arrow tells us the direction of the force, and the length of the arrow tells us the strength of the force. Class: So a longer arrow is a bigger force? Dr. P: Right! And these electric forces change size based on how close or far away the positive and negative charges are from each other. You’ll see what I mean. So a longer arrow is a bigger force?

  15. Dr. P: The positive charges want to push away from each other… Dr. P: The negative charges also want to push away from each other… Dr. P: But the closest charges—the positive and negative charges that are nearest to each other—both want to pull towards each other, and being closer means stronger. Class: Wait! We see it! The attraction will win out, here. Wait! We see it! The attraction will win out, here.

  16. Dr. P: You’ve got it. The “net” or overall force that results is an attractive force. Dr. P: So, if it’s just these two particles near each other, they will try to move toward each other. Here, I’ll draw in the force arrows that represents this net-force. Class: Okay, that makes a lot of sense. Dr. P: This net-force acting on the particles serves to keep the particles connected. Okay, that makes a lot of sense.

  17. Class: Alright, we are getting it, now. Thanks for explaining that! Dr. P: Always welcome. Dr. P: And don’t worry, I know what your next question is: “But aren’t they supposed to be MOVING”?? Class: lol! Yep, you got it! Dr. P: Well here, let me animate this a little bit. I will add in some more particles to give you a better idea. Alright, we are getting it, now. Thanks for explaining that! lol! Yep, you got it!

  18. Class: Wow, that’s pretty cool! Class: So, more particles need more arrows? Dr. P: The more particles you have near each other, the more “neighbors” each particle has. For every neighbor, you have another attractive force. Dr. P: See how they’re seeming to fight for control over each neighbor’s attention? Imagine trillions of these particles sharing a “neighborhood.” Wow, that’s pretty cool! So, more particles need more arrows?

  19. Dr. P: Remember how I told you that we could imagine springs being in between each particle? Class: Sure! Dr. P: Well watch this. We can replace the charge-signs and the force arrows with these imaginary “springs.” Dr. P: Simpler, no? Class: Hah, definitely! Easy way to think of them. Sure! Hah, definitely! Easy way to think of them.

  20. Dr. P: That’s what models are all about. Making things simpler to understand. They let us study the ideas behind science without actually getting bogged down with all the small stuff. Class: It’s the small stuff that can be confusing! We’re all glad we have the spring model to help us understand. Dr. P: Well, now that you have the spring model, would it be too much of a stretch if I made the “springs” invisible? It’s the small stuff that can be confusing! We’re all glad we have the spring model to help us understand.

  21. Dr. P: There—no springs! Has anything changed? Class: Nope! Everything’s the same as before. Dr. P: Does that make sense? Class: Sure! The springs and arrows were all just models to help explain WHY the particles do what they do. Dr. P: Well done. Now you better understand what is going on between particles that make up materials. help explain WHY the particles do what they do. Nope! Everything’s the same as before. Sure! The springs and arrows were all just models to

  22. Class: Well thanks very much Dr. Particulate! Class: We’ve learned SO MUCH from you today! Dr. P: That’s great to hear! There’s more to learn, of course, but I’m sure that your teacher is well prepared to teach you all about particles. Class: Definitely! We’re looking forward to learning more  Dr. P: If you need me again, just use the Instant Messenger program. I’ll be around. Dr. P: Enjoy the adventure! Goodbye =) Class:We will! Thanks again! Bye! We’ve learned SO MUCH from you today! Definitely! We’re looking forward to learning more  We will! Thanks again! Bye! Well thanks very much Dr. Particulate!

  23. Please wait… Closing SciMaster Instant Messenger 2.1.0 program… Shutting Down Computer…

  24. What next? Well that was great of Dr. Particulate to tell us all about how electric forces govern the way particles of matter interact! Are you psyched to learn more? Hmmm…I wonder…what’s the difference between between a SOLID, a LIQUID, and a GAS?? We will be using the spring-model again to help explain how particles interact in these different forms.

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