2. Methods
2.1 Equipment
This is a list of the equipment that we are using for our experiment.
2.1.1. Equipment List (Lab)
1)1x NE51-Van de Graaf generator
2)1x E55-Multimeter (Digital)
2.1.2. Equipment list (Self-procured)
7x Thick insulated copper wire (check the diameter at the shop)
3x Lightbulbs
1x Screwdriver
3x Jars (same type that can contain up to 680ml)
1x Aluminium foil (outside: 37.5cm, height 8cm)
500g Salt
2 liters of Water
3 screws (same type)
2.2 Diagram
[Fig 2.2.1] The setup for our experiment.
2.3 Procedures
2.3.1 Procedures for Experiment
2.3.1.1 Procedures for Experiment 1
1)Turn on the air-conditioning in the physics lab for 45 minutes (19 Degrees Celsius)
In the meantime
1.1)Set up the van de graaff generator (See 2.3.2.3)
1.2)Connect the leyden jar to the dome of the van de graaff with masking tape.
1.3)Connect the grounding wire to the outer foil of the jar with masking tape.
2)Charge the Van de Graaff generator for 2 minutes
3)Measure the voltage in the jar.
4)Turn off the Van de Graff generator
4)Repeat steps 2-4 with the water leyden jar with different concentrations of salt till sufficient data is collected.
2.3.1.2 Procedures for Experiment 2
1)Turn on the air-conditioning in the physics lab for 45 minutes (19 Degrees Celsius)
In the meantime
1.1)Set up the van de graaff generator (See 2.3.2.3)
1.2)Connect the salt water leyden jar to the dome of the van de graaff with masking tape.
1.3)Connect the grounding wire to the outer foil of the jar with masking tape.
2)Charge the Van de Graaff generator for 2 minutes.
3)Measure the voltage in the jar.
4)Turn off the Van de Graff generator.
4)Repeat steps 2-4 with a different type of jar (different surface area of foil on jar) till sufficient data is collected.)
2.3.2 Procedures for Making of Leyden Jar and Operation of Van de Graff
Generator
2.3.2.1 Leyden Jar (Salt Water)
1)Obtain glass jar
2) Peel off any stickers around it, and wrap the outside with aluminum foil (length: 37.5cm, breadth max 10cm.
3)Make a hole on top of the lid, and then glue a wire into it.
4)Fill the jar up with water. Add the needed salt (180g as of Experiment 1) used for testing. Make sure the wire is in contact with the water
5)Tape a wire the the exterior to be used for grounding.
2.3.2.2 Leyden Jar (Foil)
1)Obtain glass jar
2)Remove all stickers around it and wrap the exterior with aluminium foil.
3)Make a hole on top of the lid, and then glue a wire into it.
4)Wrap the interior of the jar with aluminium foil.
5)Tape the wire run through the lid to the interior foil
6)Tape a wire to the exterior foil to be used for grounding.
2.3.2.3 Van de Graaff
1)Place the Van de Graaff on a solid, flat surface.
2)Plug the Van de Graaff into a power outlet.
3)Flick the switch.
2.4 Risk Assessment and Management
We are going to utilise Leyden Jars, Van de Graaff generators and wires. If electricity is handled improperly, the high voltage that can be stored in the leyden jars can cause serious injury and can potentially electrocute someone or destroy expensive research equipment.
We will wear insulating/safety gloves that protect against electrocution or simply being more careful handling items that contain/generate electricity. Do not touch water or any liquids during experiment. We will ensure that distance is kept from potentially hazardous equipment to prevent burns from overheating of equipment or arcing electricity(if applicable). We will make sure the experiment is conducted in a dry environment. Leyden Jars, if constructed in appropriate size and manner, can deliver a fatal shock. We cannot build jars larger that 30x30 cm approx. else it would be lethal.
As the Van de Graff generator is used for our experiment, we made the following precautions, such as:
1. Plug the generator into a grounded (3-prong) 220 volt 50 Hz outlet only.
2. Do not operate in a wet or damp location or outdoors (to avoid shock).
3. Check for loose, worn or frayed wires. Replace any defective parts. (See parts list).
4. Since discharge of electricity can damage electronic devices, keep away from appliances such as televisions,
computers, stereos, microwave ovens.
5. The shock caused by touching the generator directly is not harmful and is similar to the shock received when walking across a carpet and touching a metallic object. It may feel uncomfortable however and should therefore be avoided.
2.5 Data Analysis
2.5.1 Hypothesis(1)
The greater the concentration of salt, the greater the amount of short circuit voltage stored in the Leyden Jar.
Plot a table of concentration of salt (g) against different tries for various concentrations of salt as follows:
Concentration of salt
|
40g
|
60g
|
80g
|
100g
|
120g
|
140g
|
160g
|
180g
|
200g
|
Try 1
| |||||||||
Try 2
| |||||||||
Try 3
| |||||||||
Average
|
2.5.2 Hypothesis(2)
The larger the surface area of the foil, the more amount of electricity the jar can store.
Plot a table of breadth of foil (cm) against different tries for various different sizes of foil as follows:
Breadth of foil
|
2cm
|
4cm
|
6cm
|
8cm
|
10cm
|
Try 1
| |||||
Try 2
| |||||
Try 3
| |||||
Average
|
From these tables, we should be able to plot graphs and determine whether our hypotheses are right or not.
