Lab - DC Circuits:
https:
phet.colorado.edu/sims/html/circuit-construction-kit-dc/latest/circuit-construction-kit-
dc_en.html
Step I: Simple Circuit (Single Battery)
Create a simple circuit with one battery (1.5V), one light bulb, a switch and two wires.
- To adjust the voltage on the battery simply click on the battery itself and a slider should
appear that lets you adjust the voltage
- Use the meter to measure the voltage drop across the bulb (Place one end of the meter probe
at one contact point and the other probe at the other contact point. Contact point is where
the wire is touching the bulb. V = _____________
https:
phet.colorado.edu/sims/html/circuit-construction-kit-dc/latest/circuit-construction-kit-dc_en.html
https:
phet.colorado.edu/sims/html/circuit-construction-kit-dc/latest/circuit-construction-kit-dc_en.html
- Connect the meter so you can measure the cu
ent through the bulb. Disconnect one contact
point from the bulb and connect the meter from the disconnected point to the bulb to
measure the cu
ent. I = _____________
Step II: Simple Circuit (Two Batteries)
- Add one more battery. Make sure to connect the positive end to the negative end of each
cells. This is called a series connection for the batteries.
- How does this affect the
ightness of the bulb?
- Connect the meters as in the previous step and record the voltage and the cu
ent.
V = _____________ I = _____________
Step III: Series Circuit - A series circuit has only one path for cu
ent to flow
- Create a series circuit connecting a single battery (1.5V) and two light bulbs.
- Observe the
ightness and record the voltage across each bulb and the cu
ent through the
circuit.
V1 = _____________ V2 = _____________
I1 = _____________ I2 = _____________
- Now add a third bulb and observe how the
ightness of each bulb is affected. Describe your
observation.
_____________________________________________________________
Step IV: Parallel Circuit (Single Cell)
Create a parallel circuit (two bulbs one battery)
- What is the difference in the
ightness of the bulbs between the series and parallel circuits?
Why do you think this difference exists? Measure the voltage across each bulb and the cu
ent
through each bulb and record your values.
V1 = _____________ V2 = _____________
I1 = _____________ I2 = ______________
Lab – Electric Charge and Coulomb’s Law:
https:
phet.colorado.edu/sims/html
alloons-and-static-electricity/latest
alloons-and-static-
electricity_en.html
Firstly, we will look at electric charges and how they behave!
Take the balloon and move it across the left arm of the sweater, collecting the electrons from it, it
should look like this:
What do you observe when you
ing the balloon close to the wall? What happens when you drag
the balloon to the midway point between the wall and sweater and release it?
Repeat this process a few times by resetting the balloon and this time collecting a few more
electrons than you did originally. What changes as you collect more electrons with the balloon?
Why do you think these changes are occu
ing?
https:
phet.colorado.edu/sims/html
alloons-and-static-electricity/latest
alloons-and-static-electricity_en.html
https:
phet.colorado.edu/sims/html
alloons-and-static-electricity/latest
alloons-and-static-electricity_en.html
https:
phet.colorado.edu/sims/html/coulombs-law/latest/coulombs-law_en.html
Coulomb’s Law is an experimental law of physics that lets us find out the force between two
stationary, charged particles. The law states that the magnitude (size) of the electrostatic force of
attraction or repulsion between two charges is proportional to the magnitude of the charges and
inversely proportional to the distance between the charges. This is expressed by the equation:
Where F is the force (measured in Newtons), q1 and q2 are point charges (measured in micro
Coulombs, 10-6, r is the distance between them (measured in cm, but please convert it to meters for any
calculations), and K is a constant (known as Coulomb’s constant) that is equal to approximately 9*109
(and whose units are N*m2/C2).
In this lab we want to look at how the magnate of the charges and the distance between them impacts
the attractive or repulsive force between them.
When you first open the simulation, it should look like this:
https:
phet.colorado.edu/sims/html/coulombs-law/latest/coulombs-law_en.html
Complete the table below using the simulation while making sure that you change the values of q1, q2,
and r in each trial. Make sure to include at least one trial that includes different combinations of the
charges (meaning negative and positive charges). Don’t forget to include the negative sign in the table
if the charge has a negative magnitude. Record the value for the force on q1 and q2, respectively and
then find the Net force on the system by finding the sum of those forces (remember that forces are a
vector quantity and should be treated as such).
q1 q2 r r2 Force on
q1
Force on
q2
Net Force
of the
system
Calculated
k value
Conclusion:
1. Using one of the trials from the table above please calculate F using the formula on page
one. Show your work.
2. If you have two point charges with the same magnitude and the distance between them is
halved, what happens to the force between them? Will the force be attractive or
epulsive? (You can use the simulation to investigate)
3. If you have two point charges with the same magnitude and the distance between them is
doubled, what happens to the force between them?
4. Does your calculated value of k change?