2-9 Knowing more 2.3

• Natuurkunde
• Middelbare school
• havo, vwo
• Leerjaar 2

Electricity in gasses

and liquids (p. 83)

What you need:

- Textbook, writingbook, iPad

- Pen, pencil, geotriangle

- Calculator

Schoolbags in the cuboard

Phones in the phonebag

Bluetooth 

- ON

- VPN off

    Lesson today:

- Lesson goals (5 min)

- Content (10 min)

- Working by yourself 

     (8 min)

- Corrections (5 min)

- Time to make the test yourself (17 min)

- Conclusion (5 min)

For the next lesson, bring a photo of your consumer unit (meterkast)

                       Lesson goals:

- Explain if gasses can conduct an electric current, and if yes, under which conditions.

- Explain if liquids can conduct an electric current, and if yes, under which conditions.

Electricity in gasses

• A high voltage in a fluorescent tube 
  

        causes it to flicker and then a 

        continuous current can flow.

• Something similar happens with lightning. The high voltage between the cloud and the ground creates a channel of conducting air. 
• The cloud discharges a current of 100 000 A.
  

Electricity in liquids

• If you touch the two terminals of a 
  

        rectangular battery to your toung, 

        you can feel a tingeling sensation. 

• If you hold the termals of a rectangular battery up against your skin, you dont feel anything. 
  
• This is because there are fluids on your toungue that contain disolved salts, and this conducts electricity.
  

In the bathroom

• In wet rooms such as bathrooms 
  

       or kitchens, you should therefore 

       be extra careful with electricity.

• A damp skin is a better conductor than a dry skin.
  
• When an electric current passes through a body, the muscles contract. This is how we controll our muscles.

ECG (electrocardiograph)

An ECG records the electrical activity of the heart. 

This is shown as pulse traces on a monitor.

What causes a gas to conduct an electric current?

1. High voltage
2. Electrons
3. High current

What causes a liquid to conduct an electric current?

1. density
2. colour
3. mass
4. salt

What does ECG stand for?

1. electrocardiograph
2. electrocardiogram
3. electricity-capacitygram
4. energycardiograph

What do you know about current in a series circuit?

1. It keeps on decreasing
2. It keeps on increasing
3. It stays the same

What do you know about the current in a parallel circuit?

1. It is the same everywhere
2. Current in a side branch is less than that in a main branch
3. There is no specific rule

Inside a plasma light is a vacuum.
There is absolutely nothing inside.

1. true
2. false

A fluorescent tube flickers to cause conductivity in the gas.

1. true
2. false

Electrons have a blue purple colour.

1. true
2. false

Fresh water is a better electric conductor than salt water.

1. true
2. false

A heart rate meter makes use of an electric current.

1. True
2. False

Now do  58 to 61 (p. 83)

WHEN YOU ARE DONE: Research conductivity of liquids online

RULES:

• Write in your writingbook
  



• Use: Your textbook
• No discussion
  


• In 8 minutes we will discuss the answers
  

Conclusion:

• A gas can conduct a current if the 
  

       voltage is high enough.

• Liquids can also conduct a current. 
  
• A liquid is especially a good conductor if there are disolved salts in the solution.