Category Archives: How does it work?

How does a see-saw work?

A see-saw (teeter-totter) is a advice that we often see in the children’s park. It is an advice that children use to play a game which is really full of fun. In this game, two persons (children)  of unequal weights sit on the ends of a wooden plank and go up and down alternately. The plank moves on the lever that can lift heavy objects using only a little force.

If the riders of the see-saw weigh equally and sit at the same distance from the center (fulcrum), the plank will balance.

But if the rider weigh unequally, the plank will move with the heavier rider going down and the lighter one riding up. In order to play, the rider pushes the ground with his feet. As the result, it goes up and the other rider comes down. This goes on in turn for the riders and they enjoy the see-saw ride a lot.

Remember that when the rider goes up, it is SEE (TEETER). But when he comes down, it is SAW(TOTTER).

see-saw (teeter-totter)


– Plank :បន្ទះក្តារ

– Alternately : ឆ្លាស់គ្នា

– Force : កំលាំង

– lever :​ ឃ្នាស់

fulcrum : កំណល់

How does neon-light work?

Neon is the name given to a colorless gas that is present in the atmosphere in a very small proportion-1/65,000th of the air. And a neon-light is the colored light produced when electricity passes through the gas in the bulb or tube with low pressure.

In a neon-light, a glass tubing is filled with neon gas. An electric current

How does a hot-air balloon go up?

Who doesn’t know that anything can rise/fly in the air only if it is lighter than the air. Accordingly, a balloon rises because the gas inside it is lighter than the air outside it. The gas filled in the balloon is helium which is lighter than the air. Hot-air balloons are filled with air that is heated and made lighter the cold air outside the balloon. And we know that hot air is lighter and it rises up according to the law of convection.

In a hot-air balloon, there is a burner outside it. This burner runs on gas that come from the bottle. The air heated by the burner goes into the balloon and inflates it. It is then that passengers get into the basket that hangs from the rocking in the wind.

The rising or coming down of the balloon is controlled by turning the flame of the burner up or down. The person who flies the balloon is called a balloonist.

Hot-air balloon


– helium : អេលីយ៉ូម (ជាតិឧស្ម័នម្យ៉ាង)

– rises up : ហោះឡើង

– convection : គោលការណ៍បំលាស់ប្តូរកំដៅរបស់អង្គធាតុរាវ

– inflate : បំប៉ោង

– basket : កន្រ្តក

– rocking : ញ័រ

– flame : អណ្តាតភ្លើង

How does a miror reflect an image?


How does an electric iron work?


How does a maximum-minimum thermometer work?


How does a bicycle work (move)?

A bicycle is one of the commonest and most successful man-powered machines used for traveling the world over. To go around riding a bike wastes nominal energy as only a little friction between its wheels and road has to be got over.

The pedals and wheels of a bicycle are mounted on ball-bearings. As the result, they can turn around very easily. If you are traveling down a slope, you need not pedal even. The bicycle will move at a faster speed due to the earth’s gravity.

Gears in a bicycle make it easier for the bike to move. The gear-levers shift the chain from one set of toothed wheels to another set. The chain indeed connects on a small chain-wheel to a large gear sprocket on the hind wheel.

Brakes are there to stop the moving bike whenever we like to do so. Bicycles for ladies have a low cross-bar so that they can cycle even when wearing a long skirt.



– nominal : ស្តួចស្តើង

– friction : កកិត

– pedals : ឈ្នាន់

– mounted : ដាក់

– ball-bearings : ដុំកង់

– toothed : ធ្មេញរបស់ដុំកង់

– sprocket : ថាស់កង់

– hind wheel : កង់ក្រោយ

– low cross-bar : តួកង់ស្រី (គ្មានដែកកាត់ត្រង់​នៅលើតួកង់)​

How does the boat float?

Who doesn’t know that a piece of wood floats on the water but a piece if iron sinks in it. Why? Because of the piece of wood is very light but a piece of iron is heavy. But a boat, thought made of wood and iron doesn’t sink in the water. It floats not only itself, but along with scores of passengers in it also. Why is it so? Let us try to understand the reason.

When any thing (ay a boat) enters water, it pushes some water downwards, with a certain force. As a reaction , the water pushes the boat upwards with certain force. The process is the result of the law: every action has an equal and opposite reaction.

Now if the upward-pushing force of the water is greater than the downward-pushing force of the boat, the boat float on the water. But if it is otherwise, the boat is sure to sink. So boats are made in such a way that they should displace such in quality of water as would exert an upward force larger than that the boats exert downwards. As the result, they do not sink but float.



– Float​ : អណ្តែត

– Force : កម្លាំង(សង្កត់)

– Reaction : ប្រតិកម្ម

– Exert : ប្រើ