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Static Electricity & Charge


Akoranga 1 Mahi Tuatahi

On the board, brainstorm all the things you can remember about electricity from Year 10!



Te Whāinga Ako

  1. Explain how static electricity is created by the removal or addition of electric charge (and is measured in Coulombs)

Write the date and te whāinga ako in your book


Static Electricity

Static electricity has many effects - some dangerous, some hilarious, but they all depend on charge!

Static Electricity


Charges: Positive & Negative

From Year 10 we should all remember that, much like magnets, opposites attract and likes repel.

Electric Charges


Charge Carriers

Recall: the atom. What element is this? What are the three subatomic particles that make it up?

Draw this diagram in your book and label the particles and the charge they carry.



Pātai: What happens when an atom loses or gains electrons?


Ions

Source


Pātai Tahi

What did we do in Year 10 Pūtaiao to remove charges from one object and put them onto another?


Whakatika Tahi

We applied friction!


Van der Graaf Generator

Van der Graaf Generator


Akoranga 2 Mahi Tuatahi

Working with the person next to you, describe the process of generating a spark using the Van der Graaff Generator. Start with the motor, the brush, the dome and then go to the wand and spark.

Van der Graaf Generator



Te Whāinga Ako

  1. Explain how static electricity is created by the removal or addition of electric charge (and is measured in Coulombs)

Write the date and te whāinga ako in your book


What is Charge?


So, What is a Coulomb?



\begin{aligned} num_{e} &= \frac{Q_{total}}{q_{e}} \newline num_{e} &= \frac{1}{1.6 \times 10^{-19}} \newline num_{e} &= 6,250,000,000,000,000,000 = 6.25 \times 10^{18} \end{aligned}

$6.25 \times 10^{18} electrons = -1 C$

$1C$ is the amount of charge carried by $6.25 \times 10^{18}$ electrons.


Pātai Rua

If a balloon has charge of $-3C$: did the balloon lose or gain electrons, and how many?


Whakatika

If a balloon has charge of $-3C$: did the balloon lose or gain electrons, and how many?

\begin{aligned} & \text{Negative C} \rightarrow \text{electrons gained (-ve charge)} \newline & num_{e} = 3 \times (6.25 \times 10^{18}) \newline & num_{e} = 1.875 \times 10^{19} && \text{ electrons gained} \end{aligned}


Akoranga 3 Mahi Tuatahi

If Charlotte has charge of $0.2C$ did she lose or gain electrons and how many?


Whakatika

If Charlotte has charge of $0.2C$ did she lose or gain electrons and how many?

\begin{aligned} & \text{Positive C} \rightarrow \text{electrons lost (+ve charge)} \newline & num_{e} = 0.2 \times (6.25 \times 10^{18}) \newline & num_{e} = 1.25 \times 10^{18} && \text{ electrons lost} \end{aligned}


Ngā Whāinga Ako

  1. Be able to define current
  2. Be able to calculate current using charge and time
  3. Recall the properties of conductors and insulators

Write the date and ngā whāinga ako in your book


Charge and Current

\begin{aligned} current &= \frac{charge}{time} \newline I &= \frac{q}{t} \newline A &= \frac{C}{s} \end{aligned}

Alternative definition of a Coulomb:

A current of $1A$ will carry $1C$ of charge past a point in $1s$.


Task/Ngohe

Worksheet One Q1-4


Conductors

Source


Insulators



Task/Ngohe

Homework Booklet Q1a