MINI-INTERACTIVES:
Things
that move | Invisible Forces
| Shining & seeing | Patterns
in water | Touring etc.
| Hong Kong
Installed in a school library (a short video clip)
Invisible
forces
Feel the forces.
Doesn't it feel strange when two things push apart!
The red and blue colours show the "north" and "south"
ends of the magnets. Which ends pull together and which push apart?
Make sure the chain is not touching the table or anything else.
Rub a balloon on your clothes to produce an electric charge. Can you make
the very thin "gold-leaf" move, in the middle of the electroscope?
What happens if you touch the top of the electroscope or the chain while
the "gold-leaf" is sticking out sideways?
Slowly slide the magnet up and down with the red bar.
Can you see the magnet? What can you discover about the way the tiny pieces
of iron move in the clear oil?
A magnetic field makes curved shapes in the space near the
magnet. Can you discover any curves in the patterns made by the joined-up
pieces of iron?
Rub the clear plastic cover with a dry hand.
Or rub a balloon on your clothes and bring it near. How much can you discover
about the way the pieces of paper move?
By rubbing, you separated positive and negative charges. Positive and
negative charges attract each other, but similar charges are forced apart.
Can you make an electric current by moving the magnet near the coil?
You will need to close the circuit, using the loose wire.
The small, black diode near the loose wire only lets current
flow in one direction. What difference does it make if you touch the wire
against the screws at either end of the diode?
Feel the forces between the hanging magnets.
Doesn't it feel strange when two things push apart!
The red and blue colours show the "north" and "south"
ends of the magnets. Which ends pull together and which push apart?
The compass needles are sensitive at a considerable distance from the
coloured bar magnet and show the shape of the magnetic field.
The hovering ring-magnets have red and blue coloured faces to indicate
their north and south poles.
Rotating one of the bar magnets by hand immediately causes the other
one to flip round. This is a strangely appealing phenomenon to "play"
with...
Holding down the red button causes a green LED to flash in the battery
box. The motor's internal magnets have been removed, so it does not rotate
unless the bar magnet is brought close to the coil while the current is
flowing. The direction of rotation can be reversed by reversing the magnet
or by moving it to the opposite side of the coil-commutator assembly.
Can you find out which of the six mounted specimens conduct an electric
current and which do not?
A buzzer and an ammeter indicate current flowing when both wires touch
something which conducts an electric current. Also try things from your
pocket: coins, keys, credit cards…
Magnetic compasses must be carefully adjusted to function in steel
ships.
A simple magnetic compass is mounted in the centre of the ship.
Four rotatable plastic knobs, each approximately 25mm diameter, are symmetrically
positioned around the compass. One pair fore-and-aft and one pair athwartships.
Each knob is coloured red and blue and contains a small magnet. A red
plastic cylinder is attached to the bench up to 150mm to the (magnetic)
north of the centre of the base disc. This contains a stronger magnet,
aligned with the earth's magnetic field (not necessarily with the possibly
distorted field surrounding the exhibit).
The challenge is to adjust the four rotatable magnets such that the compass
points north whichever direction the ship is facing.
Press any of the red buttons while turning the handle.
Notice the extra effort needed when you switch the light bulbs on. The
energy that lights them has to come from somewhere. It comes from you.
It is harder work to supply enough energy to light more lamps or lamps
rated at a higher 'wattage'.
The ammeter shows how much current is flowing.
MINI-INTERACTIVES:
Things
that move | Invisible Forces
| Shining & seeing | Patterns
in water | Touring etc.
| Hong Kong
Installed in a school library (a short video clip)
|
