Name: ______Block: ______Date: ______
Save as “Balloon” in EM subfolder
Balloon & Static Electricity
Go to Google and search “PhET Simulations”. On the left side of the page, click on “Electricity, Magnets & Circuits.” On the right side of the page, scroll down to find the “Balloons & Static Electricity” simulation. It is a Java file. You may download Java for free from java.com.
This simulates the most common case of electrostatics is static cling without showing any charges. We will watch it again with charges, but not right now!!
SELECT
START: An unruly balloon is used in the following simulation. As you are most likely aware, charge can be described as either positive or negative. When + or – charges are present in roughly equal concentrations, the object is said to be neutrally charged.
Large numbers of the negative particles (or electrons) can be transferred in certain circumstances from one neutral surface to another. This generates an object with an excess of + charges and an object with an excess of – charges. The simulation illustrates the movement of both + and – charges and therresulting attractive and repulsive forces.
ACTIVITY-1: Balloon
Part-A: No charges showing
1)Describe what happens when the balloon is rubbed against the wall.
_
2)Predict what will happen when the balloon is returned to the center of the room.
_
Now drag to the center and confirm your prediction.Did you predict it right? ____
3)Now rub against the Sweater; and see if it clings. What happened? Explain why it happened; what changes to the balloon and to the sweater, respectively.
__
Predict what will happen when the balloon is returned to the exact center of the room. Confirm your prediction by using Phet.
4)Formulate a hypothesis on why it goes towards the sweater and not the wall.
___
5)Use your hypothesis to predict what will transpire when the balloon is placed gradually closer to the wall, but not touching the wall-INDUCTION. Once you tried it, what happened?
___
Part-B: Charges showing Run this experiment again, Starting from 1 or 2, but showing the charges.
MAKE SURE TO PRESS RESETand Select
Revise 1-5; your hypothesis and answers to include this new observation. You want to address both how opposite charges interact and how like charges interact.
6)Why won’t the + charges move from the wall to the balloon?
__
7)How come in the sweater the + and – separate, but on the wall they don’t? __
- This shifting of charges on the neutral wall is called charging by induction.
- The non-conducting objects, like the wall remain neutral but become polarized.
- The transfer of charges to another object is charging by rubbing or friction.
ACTIVITY 1: Lab Questions:Answer questions #1-4 using COMPLETE SENTENCES!!!
1.Play with the simulation and observe what happens when the balloon is rubbed on the sweater. Explain why this happens. __
--The process you completed in #1 is a called charging an object by friction.
2.Bring your charged balloon near the wall and describe what happens to the wall. Explain why this happens. ___
The effect you observed in the wall in #2 is called polarization. This shifting of charges on the neutral wall is called charging by induction.
3.Now, take your charged balloon and place it somewhere between the wall and the sweater. Observe what happens, and describe it here. How does distance affect the force by which the balloon is being pulled. Explain. ______
4. Write a correlation using the word distance and electric force & increases /decreases.
_
5. Considering that the total system includes 3 objects; the sweater, the balloon and the wall; has the net charge in the system changed during this experiment? If yes, explain what changed. If no, explain why not.
__
DIRECTIONS:
After doing the simulation without and with charges; review SHORT answers.
Save as a word document and as a PDF document. (both bc I need to try to grade your work and I need to test what works best).
Save your files as “Balloon” inside your EM subfolder in the Google drive that you shared.
DO NOT NOTIFY ME BY e-mail.