Use the following simulationto study “Ohm’s Law”:

1. Raise the voltage until you have 9V.  How many 1.5 V batteries does it take?  Take a picture of this with Command-Shift-4.

2. Decrease the Amount of batteries and come up with a rule for how the number of batteries effect the Voltage in the circuit.

3. As you increase the Voltage, what happens to the current?  Take a picture with Command-shift-4.

4. As you decrease the Voltage, what happens to the current?

5. As you increase the resistance, what happens to the current?  Take a picture with Command-shift-4

6. As you decrease the resistance, what happens to the current?

Use the circuit construction kit here  to create all six circuits on the board.

1. You need to right-click or Control-Click to change the resistance of the light to the proper value.

2. Set up a voltmeter across the light or lights, and an ammeter somewhere in the circuit.

3. Take a picture of each circuit with Command-Shift-4 and put your circuit in a comic.

Create a ten square comic with these images as well as captions explaining what is important in each picture and what the picture shows.  Title it “Ohm’s Law”

Use this simulation to learn about resistance.

“Battery-Resistor”:

Check “show inside battery” and “show cores”, watch what happens, adjust some variables and play a little.

1. Why do electrons (blue dots) move? What’s pushing them?  Draw a diagram of the battery, label the flow of electrons.

2. What does the Ammeter (on the left) measure? How is this shown in the sim?

3. What role do the “green dots” in the resistor play in the sim? What do you think they represent?  How do they change as you turn the resistance up and down?

4. Increase the resistance (# green dots). What affect does this have on temperature? WHY?

5. To make the circuit “cold”, what do you need to do? WHY?

6. Describe the relationship between voltage and temperature.

Use the following simulation: “Resistance in a Wire”

1. In this sim, R is the resistance, rho (ρ) is the resistivity, L is the length of the wire, and A is the cross sectional area (thickness) of the wire.  Write down the formula in your notes and write down what each variable stands for.

2. Try increasing the resistivity (ρ) of the resistor. What changes in the resistor?

3. Now increase the length (L). What happens to “R”? WHY?

4. Now increase the area (A) of the resistor. What changes? WHY?

5. Write a summary about the different relationships you looked at in the properties and measurements of a resistor.

Use the following simulationto study “Ohm’s Law”:

In this sim, vary the values of Resistance (R), Current (I) and Voltage (V).

1. Find  three different combinations of V and R which get a current (I) of 6 mA  (milliamps)?

2. Describe the relationship between I and R. Why is this?

3. What would happen to the current if you could decrease the resistance to 0? Explain why in terms of resistance and the flow of electricity.

To understand voltage in a circuit, construct the following circuit:

Click the box to create a voltmeter and use the two electrodes to test the voltage of your battery.
 Then test the voltage across the light.  Be sure to keep the electrodes in the order they are in the image below:

1. Draw the circuit and label the voltage across the battery and across the light.

Now add a light to the circuit like this:

2.  Draw the circuit in your notes, measure the voltages across the battery and each of the lights, and label the voltages across each light.

3. How do the voltages across each light compare to the voltage across the battery?

4. Add another light and test the voltages.  These lights in a row are what’s called a “SERIES” circuit, because each light is in series.  Write a statement explaining how voltage changes in a series circuit.

Now you will create what is called a “PARALLEL” circuit and test its voltages.  Make this circuit:
5. Measure the voltage across the battery and each light.  Be sure to keep the red electrode on the top and the black on the bottom. Draw the circuit and label the voltages.

6. Add another light, draw the circuit, and label the voltages.

7. How do voltages change in a parallel circuit?

Freezing Flowers and Exploding Cans Make Physics Exciting

Run the simulation here, draw it in your notes, and answer the following questions:

1. What is the current through the circuit when the battery voltage is zero?

2. What happens to the current as voltage increases?

3. Write what you found in #2 as a rule or a statement about voltage and current.

Run the Circuit Construction Kit here.

4. Create a circuit like this one and draw it in your notes.

Create a Non-Contact Ammeter by clicking the box in the tools section.

Put the Ammeter over a wire and measure the current through the wire.

5. Move the ammeter to another wire and all around your circuit.  Label each wire with the current that is going through it.

6. What you have just found is called “Kirchhoff Law.”  Look it up and explain how it applies to your circuit and what you found.

7. Add another light like this:

8.  Measure the amperage around the circuit.  Complete this sentence: Twice the lights gives you ___________ the current through the circuit.

9. Add another light and write a similar sentence to #6.

10. Delete the lights and replace them with resistors.  Do resistors work the same way as lights?  What’s the difference?

11. Create a circuit like the following circuit:
Draw the circuit in your notes and measure the current through each wire.  Label each wire with the current going through it.

12. How does the current split when it has two paths to go through?

13. How does the current split when it has three paths to go through?

About two minutes after posting my project, I got my first backer. Doug Buckley supported the project with a $500 donation! Thanks Doug. You and your company are now associate publishers of the book.

And as I was writing this, another backer popped up! Thanks Scott for your donation! Woohooo!

Click here to see how a battery works.

1. Click the box to show the battery.  Draw the battery in your notes and label the positive and negative side clearly.  The positive side of the battery is always the side with the extra knob on the end and the negative side is always the flat side.

2. With the voltage of the battery in the middle (dead battery), how many electrons are present on each side? You don’t have to count, just estimate.  Same, more on left, more on right.

3. Slide the “Desired Voltage” control to the right a little. Draw the picture in your notes and explain what this does to the amount of electrons on either side of the battery.

4. Slide the “Desired Voltage” control all the way to the right.  You now have a fully charged battery. Draw the picture in your notes and explain what this does to the amount of electrons on either side of the battery.

5. Draw the battery and explain which side is the positive and which side is the negative side of the battery, and why.

6. What would happen if you connected a wire from the positive to the negative side of the battery?

Conductivity

Use this simulation to study conductivity.

1. This simulation shows what happens when you connect a wire from one end of a battery to the other.  Draw the picture in your notes.  Increase the voltage of the battery by clicking the up arrow once.  Explain what happens to the electrons in the battery and the wire.

2. Slowly increase the voltage and explain what happens to the electrons as you increase voltage.  Also explain what happens to the energy of the electrons as voltage increases.

3. Switch the material to plastic and explain what happens to the electrons.

Circuits

Run this simulation to study circuits.

1. Pull out a battery, a light, a switch, and wires to make a circuit that looks like this:

Close the switch and explain what happens to the electrons and what happens to the light.

2. Open the Grab Bag and put a dollar bill in your circuit (right-click or Control-click to remove a wire) like this:

Is the dollar bill a conductor or a non-conductor?  Try everything in the grab bag and explain if it is a conductor or non-conductor.  You can right-click or Control-Click things to remove them.

3. Right click or Control-click on the battery and turn up its voltage.  Retry the pencil lead and the hand, and the dog to see if they are conductors.  What is needed to make them conduct electricity?

4. Turn on More Voltage and explain what happens in the circuit when the voltage gets too high.

5. Take the light out of the circuit and connect its wires together like this:

What happens when there is no light?

1. Opposite charges… (attract or repel)

2. Like charges… (attract or repel)

3. Draw the electric field from a positive charge.  Show the direction of the field with arrows.

4. Draw the electric field from a negative charge. Show the direction of the field with arrows.

5. A positive charge placed in an electric field, will have a force on it in what direction?

6. If a balloon is rubbed up against a sweater, what part of the atom is transferred to the balloon?

7. If a balloon is rubbed up against a sweater, the sweater becomes charged… (positively or negatively)

8. What is it called when charge is moved by rubbing?

9. Iridium (Ir #77) has how many protons, how many neutrons, and how many electrons in a stable, neutral atom?  Periodic Chart.

10. The element with a single proton in the nucleus is called?

11. Every atom of carbon was created where?

12. Gold and other heavy elements were created where?

13. What makes an electrically neutral atom?

14. What is an ion?

15. What is the charge of a neutron?

16. List 3 everyday examples of static electricity.

17. What are the charged parts of the atom?

18. What is the unit of charge?

19. What is the charge on one electron?

20. If a charge has 4 field lines coming out of it, and another charge has eight field lines going into it.  What can you say about the two charges?

Go to the next section and answer the following questions:
9. How do you create an electrically neutral atom?
10. What is an Ion?
11. List three common examples where electrons move from one material into another.
12. What is the unit of charge?
13. What is the charge of an electron?