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Evan Toh
Nov 41 min read
How induced current is produced when magnet is inserted into a solenoid
According to Fraraday's Law, the magnitude of the induced emg, hence induced current, is directly proportional to the rate of change of...
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Evan Toh
Nov 41 min read
Electromagnet demo
When the current flows through the solenoid, the U-shaped iron rod will become magnetised easily and strongly. When the current is cut...
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Evan Toh
Nov 41 min read
Current carrying wire + compass placed below wire
When a current flows through a wire, magnetic field is produced around the wire. This magnetic field can be detected using a compass....
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Evan Toh
Nov 41 min read
Overloading of a multi plug resulting in overheating and fire
It fine to use a multiplug as it brings convenience. The problem arises when too many high power appliances are connected and on at the...
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Evan Toh
Nov 31 min read
Changing a 2 pin-plug to 3 pin-plug
Changing the pin will not change the voltage required by the appliance.
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Evan Toh
Nov 31 min read
Simple heating element demo
The wire used here is not the typical copper wire. It is nichrome wire which has much higher resistivity compared to copper. Hence, for...
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Evan Toh
Nov 20 min read
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Evan Toh
Nov 21 min read
Balloon at reduced pressure
A partially inflated balloon is placed inside a sealed container as air is pumped out of the by syringe. As the pressure of the container...
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Evan Toh
Nov 21 min read
Marshmallow Hulk in Vacuum Jar
When the pump is switched on and the air in the jar is gradually removed, the pressure in the jar decreases. There will be fewer air...
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Evan Toh
Nov 20 min read
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Evan Toh
Nov 11 min read
Boiling water at reduced pressure – Water boils at 75 oC
At sea level (where most of us are), the standard atmospheric pressure is about 101325 Pa. The boiling point of water is at 100 oC which...
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Evan Toh
Oct 301 min read
PP2022P1Q17 Why is the athlete wrapped with silver and white sheet after a run?
We have learned that silver smooth reflective surface is a poor absorber , poor emitter or a good reflector of infra-red radiation. How...
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Evan Toh
Aug 312 min read
Pee Boy - Gas expands and contracts the most
The 3 states of matter – solid, liquid and gas. In general, when a body is heated, it expands and volume increases. The mass remains the...
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Evan Toh
Aug 311 min read
Hand Boiler
Hand boiler toy is a demonstration of thermal transfer and how the 3 states of matter interact. The coloured liquid inside is usually...
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Evan Toh
Aug 311 min read
Water is a poor conductor
In the three states of matter, in general, solid is the best conductor as the particles are closely packed in an orderly manner, hence...
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Evan Toh
Aug 311 min read
Metal is a good conductor – paper over metal gets burned slower
he paper over metal or over plastic/wood will get burned faster? Everyone knows that metal is a good conductor of thermal energy. But...
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