Lesson 1: The First physics lesson with a native speaker of English
The topic is “Electrostatic charge”
- To rub (for example: to rub a dry cloth against a piece of plastic)
- To bend
- To cover
- To spread apart
- To repel
- To attract
- To cause
- To spin around
- To charge
- To spin the wheel
- To crackle
- To get a shock
- A glass jar
- A copper wire
- A hook
- Two pieces of alluminium foil
- A vynil record
- A surface
- A piece of cloth
- A straw
- Air gap
- A tin / a can
- Rarefied air
- A spark
- A storm
- The ground
- Plastic handles
The.. the… (Examples: the faster we spin the wheel, the stronger the charge becomes; the further apart the charged things are, the weaker the forces of attraction and repulsion are.)
What is crackling?
You may have noticed that pulling off a jumper or other clothing over your head can cause crackling. If the clothing is made from a synthetic fibre then charge is transferred as it rubs against your hair. The crackling is the sound made by the charge jumping through the air between the clothing and your hair.
How can a Car Door or a Radiator give you a Shock?
Touching a car door or a radiator can sometimes give you a shock. If both the car seat and your clothing are made from a synthetic fibre, then one rubs against the other transferring charge as you step out of the car.
The charge then jumps the small air gap between your finger and the car as you go to close the car door.
Similarly, if both a carpet and your shoes are made from synthetic materials, then charge is transferred as you walk around. Touching a radiator will cause the charge to jump the small air gap between your finger and the radiator.
The sensation of the charge on your skin feels unpleasant.
How can Electrostatic Charge cause a Spark?
In the examples above, when charge jumps across a small air gap it causes spark which can be dangerous. Lightning is a natural example of a huge charge jumping across a very large air gap between the ground and
the sky, and we know how dangerous lightning can be.
A property of microscopic particles, which may be either positive (e.g. protons) or negative (e.g. electrons).
[Particles with the same charge repel each other, and particles with opposite charges attract each other. The field of force that surrounds an electric charge is called an electric field, and a river of charged particles flowing through a conductor is called an electric current.]
A negatively-charged sub-atomic particle. It is an indivisible, elementary particle, and is usually to be found orbiting the nucleus of an atom.
[Electrons in an atom (which exist in the same quantity as the number of protons in the nucleus of the particular atom, so that the overall electric charge is zero) are constrained to occupy certain discrete orbital positions or “shells” around the nucleus. Interactions between the electrons of different atoms play an essential role in chemical bonding and phenomena such as electricity, magnetism and thermal conductivity.]
One of the two main building blocks (along with the neutron) of the nucleus at the centre of an atom.
[Protons carry a positive electrical charge, equal and opposite to that of electrons, and are made up of two “up” quarks and one “down” quark. The number of protons in an atom’s nucleus determines its atomic number and thus which chemical element it represents.]
The field of force that surrounds an electric charge (in the same way as a magnetic field is the field of force that surrounds a magnet).
[Together, the electric and magnetic fields make up the electromagnetic field which underlies light and other electromagnetic waves, and changes in either field will induce changes in the other.]
Special Thanks to Olena Shlap (native speaker of English)