Science @ Siloso Sentosa

Papa and Mama brought me to Sentosa Siloso Beach for my first science excursion yesterday. Oh, I've learnt a great deal of new things! Such as...

Light has different levels of permeation through different mediums. Some mediums absorb a fraction of the light energy while allowing the rest to pass through it - such as the lens on this pair of sunglasses that I was wearing. The filtering off of some of the light energy meant that my vision of the beautiful beach would be less glaring.

And the shades looked cool on me, too.

The rectilinear propagation of light principle states that beams of light travel in straight lines while in a single medium. Because the light from the sun didn't bend around my body, the area immediately behind it was one that was obscured from the reach of the sunlight.

Hence a shadow was cast on the sandy beach.

Pressure = Force / Area

That means that the smaller the area, the larger the pressure.

Which was why I was able to easily perforate the plastic film of this mineral water cup with the sharp end of the straw. Now I know not to waste my time and poke poke poke with the flat end in the future whenever I want to have a drink.

I realised that I can get the water into my mouth by squeezing the mineral water cup.

The application of pressure onto the malleable body of the plastic recepticle resulted in a reduction of its internal volume. Since pressure is inversely proportional to volume, this meant that what I'd done created a corresponding increase in internal pressure, which in turn pushed the water up through the straw and into my parched throat.

I also discovered this alternate method to ease my thirst. When I sucked through the straw, what I was actually doing was generating a partial vacuum at the end of the straw inside my mouth. This meant that the pressure at this end was substantially lower than that at the other end in the cup.

The principles of fluid dynamics ensured that water would flow from a point of higher pressure to another point where the pressure was lower. That was how the water in the cup gets pushed up the straw and into my mouth!

Squeezing the plastic cup also demonstrated another law of physics - that of gravity.

Observe that I was able to impart an initial upward velocity to the water stream with my pressure application. This upward momentum was just negated by the forces of gravity at the apex of the stream's sinusoidal trajectory (where vel = 0) after which the water stream developed a negative (i.e. downward) velocity in its descent.

Being on the carousel ride taught me the laws of circular motion:

v = rw

where v is velocity, r is radius and w is angular velocity.

This also made me better appreciate the effects of centrifugal forces.

Papa taught me that the moment arm exerted by a cantilever weight is proportional to the distance from the weight to the fulcrum point.

That was why it was way easier for him to carry my 10kg body with his arms bent rather than having them fully straightened.

Papa is strong. But not THAT strong.

Density = Mass/ Volume

The difference in density was demonstrated with the seaweed floating on the water in my pail. The seaweed floated because its density was lower than the water medium that it was placed in.

Lastly, I've learnt the concept of surface tension, which is the phenomenon that allowed Mama's soapy solution to manifest as this pretty bubble!



I really wish I could come back to Sentosa's beaches again, soon. There are just sooo many things to learn!