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Evan Toh
11 hours ago1 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
12 hours ago1 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
12 hours ago0 min read
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Evan Toh
12 hours ago0 min read
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Evan Toh
1 day ago1 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
3 days ago1 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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Evan Toh
Aug 311 min read
How to read the digital stopwatch
Depending on the experiment, the recording of measured time may be to the nearest 0.1 s or the nearest 1 s, even though a typical digital...
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Evan Toh
Aug 311 min read
Convection Toy – Angels Carousel
This simple toy is made possible using convection current in the air. The ‘fan’ of the carousel is similar to the windmill we are...
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Evan Toh
Aug 311 min read
Convection Current – demo
Convection is a process in which thermal energy is transferred within a fluid (liquid or gas) due to the difference in density which...
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Evan Toh
Aug 311 min read
Radiometer – Thermal Transfer
adiometer is a device for measuring the amount of infrared radiation. It consists of freely pivoted rotor with four vanes perpendicular...
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