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Static Electricity

• Static electricity = charges which aren’t free to move = causes the charges to build up in one place = ends with a spark or a shock
• Negatively charged electrons are moved off one material to another material when insulating materials are rubbed together = materials are now electrically charged (positive static charge on one material and equal negative static charge on the other)
• Polythene rod and cloth: electrons move from the cloth to the rod, leaving the rod with a negative static charge and the cloth a positive static charge
• Acetate rod and cloth : electrons move from the rod to the cloth, leaving the rod with a negative static charge and the cloth a negative static charge.
• Positive charges DO NOT move. Positive and negative electrostatic charges are only produced bymoving electrons .
• Positive static charge = caused by electrons moving elsewhere
• Material loses electrons = loses negative charge = left with an equal positive charge
• Electric charge builds on an object = potential difference between the object and earth (at 0V) INCREASES
• If PD gets big enough = electrons can jump across the gap between the charged object and earth = SPARK
• Electrons can also jump to any earthed conductor which is near. Therefore, you get static shocks when you get out of the car: charge builds up on cars metal frame. If you touch the car the charge travels through you to earth
• Usually happens when the gap is small.
• Two things with opposite electric charges = attracted to each other
• Two things with same electric charges =repel each other
• Forces get weaker as the distance between objects increases
• Forces will cause the objects to move If they can = electrostatic attraction/repulsion and is a non-contact force (objects do not need to touch)

How long have you…? (present perfect 4) Exercises

Use the information given to create questions beginning with ‘How long…?’

• It is snowing.

• The weather is shining.

• John and Kate are married.

• My brother has gone on holiday.

• My aunty and uncle live in Canada.

• My sister is a teacher.

• I work at the chemist.

• I’ve known Susan since I was a baby.

• Jonathan is learning to speak to Mandarin.

Fill in the missing gaps in the sentences using the present perfect (=has/have + past participle)

• I have known Kate a long time.

• My brother has been playing the piano he was 11 years old.

• My mum and dad on holiday to America. They

gone since last Sunday.

• I Ben and Emma since primary school.

We to the same primary and secondary school.

• My sister learning to speak French because she
is going to France next month.

Use the appropriate words in the missing gaps.

have you lived       lives      to

has been       works        have known

I have bought       have worked.

• My sister in Spain. She is studying Spanish

with her friend Rosie. I Rosie since I was 5.

• Spencer like with Jamie. They have worked

together for 2 years.

• How long in Australia?

• a new dress for prom.

• He to Thorpe park.

Challenge: Create 4 of your own questions beginning with ‘How long……?’

1.

2.

3.

4.

1 2 3 4 5 6

“Every accomplishment starts
With the decision to try.” Gail Dever

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