Download Investigating Electrical Circuits with the PhET Animation

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Investigating Electrical Circuits with the PhET Animation:
Circuit Construction Kit-DC only
General instructions:
You will use one or two online animations, your textbook, section assessments, and
your guided notes to help you complete the following investigations.
Circuit Construction Kit-DC only
This animation allows you to drag objects onto the working area and move them
around. Place objects close to each other to connect them. Control-click on a
connection to see the options for that connection, including disconnecting the
objects. Clicking on an object and using the delete key on your keyboard removes
an item.
On the right side of the application, you will see some options. Click “show values”
in the options area.
Use this animation for items 1-9.
Key to this Document
Instructions are in black.
Experimental questions that you need to solve through experimentation with an
online animation are in green highlighted.
Data tables that you will fill out while experimenting are in aqua highlighting.
Items that need a response from you are in yellow highlighted.
Please put your answers to this activity in RED.
Circuit Basics
1. Using the simulation “Circuit Construction Kit-DC only”, build a circuit that lights
a light bulb, but only contains 3 components. (Also: Look in chapter 2.4 for help.)
Insert a picture of that circuit below. (use Command-Shift-4 to take a picture of
the circuit, and then drag it from your desktop to this document.)
What 3 components does every electrical circuit need to be complete?
1A.
1B.
1C.
2. It is called a short circuit when you connect the electrodes of a cell (battery)
with just a conductor and no load on the circuit. Do this on the animation. (Use
chapter 2.6 for help on short circuits)
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2A. What happens?
2B. Why does this happen?
2C. Why would we want to avoid this?
3. Please make a complete circuit that includes a switch and lights one light bulb
when the switch is closed. Insert a picture of that circuit below. (use CommandShift-4 to take a picture of the circuit, and then drag it from your desktop to this
document.)
Conductors vs. Insulators
Keep the circuit you just created in #4, and separate the wires so you can place an
object in the gap. Click on the grab bag and select each of the items so they are
all on your workspace.
4. Put each of the items into the gap to discover whether it is a conductor or an
insulator. List conductor or insulator for each item in the chart below.
Item
Dollar bill
Paper clip
Penny
Eraser
Pencil Lead
Hand
Dog
5. What do the conductors have in common?
Conductor or Insulator?
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6. Why is the pencil lead a bit different than the others?
Current
In this section, you will build the circuits under each question and use your
observations of the circuits to come to a conclusion/answer for each question. The
circuits you build do not need to look the same as the diagrams in shape; they do
need to be the same elements as shown by the symbols.
7. How is the amount of current affected by the voltage in a circuit?
You will need to change the amount of voltage in the battery, and then for each
voltage use the non-contact ammeter to measure the current. Notice also how the
brightness of the bulb changes with the amount of current.
Data Table
Voltage
Current
Conclusion:
8. How is the amount of current affected by the amount of resistance in a
circuit?
You will need to change the amount of resistance provided by the bulb, and then
for each resistance use the non-contact ammeter to measure the current. Notice
also how the brightness of the bulb changes with the amount of current.
Data Table
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Resistance
Current
Conclusion:
Series vs. Parallel Circuits
9. How does the current of a parallel circuit compare to the current in a series
circuit with the same amount of bulbs ? Measure the current of each circuit with
the non-contact ammeter found on the left. Please set the voltage of your battery
to 25 Volts by control-clicking on the battery and choosing “change voltage”.
Data Table
Number of bulbs
Current in series circuit
Current in parallel circuit
2
3
4
Use the experiments you just did to answer the following questions:
9A. How does the number of bulbs in series affect the current in a circuit?
9B. How does the number of bulbs in parallel affect the current in a circuit?
9C. How does the number of bulbs in series affect the resistance in a circuit?
9D. How does the number of bulbs in parallel affect the resistance in a circuit?
9E. What happens in a series circuit when you remove 1 bulb?
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9F. What happens in a parallel circuit when you remove 1 bulb?
Resistance
10. Now you will be using air through a straw to simulate electrons through a wire.
Blow through the drinking straw.
Next, cut the drinking straw in half and blow through a half-straw.
11. Was it more resistance or less resistance to blow through the shorter straw?
12. Cut the halves again in half, now you should have 4 quarters of a straw. With
the four pieces, blow through one, then blow through all four made into a larger,
square-shaped straw.
13. Was it more resistance or less resistance to blow through the thicker straw?
15. Next use the PhET simulation called “Resistance in a Wire” to complete the
following statements:
As wire length (cm) increases, the resistance (Ω) _________
As wire area (cm2) increases and the wire gets thicker, the resistance (Ω)_____
As wire density (Ωcm) increases, the resistance (Ω) __________
______________________________________________________________
Review Statements: use these to see if you have learned the main points of
this activity.
Underline the correct choice:
1. For a circuit to be complete there must be a(n) broken / unbroken path
for electron to flow through.
2. Conductors allow / prevent charges from flowing.
3. Short circuits are dangerous because
a. they can cause lots of heat due to electrical friction
b. they can catch on fire, or give people electrical shocks
c. they can cause an energy source like a battery to be depleted (or “run out
of electrical energy”) very quickly
d. all of the above.
Fill in the blank:
3. As the voltage in a circuit increases, the ____________________ also
increases.
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4. As the resistance in a circuit increases, the current in the circuit
__________________.
5. Wires that are thicker have ___________ resistance than thinner wires.
6. Longer wires have _____________ resistance than shorter wires.
7. When a wire has a ___________ temperature, its resistance becomes less.
8. Series circuits have __________ resistance than parallel circuits.
9. Series circuits have _________ path(s) for electrons to flow on, while parallel
circuits have ____________ path(s) for electron flow.