Science Centre Singapore

Mysterious Drinking Bird

The drinking bird toy is a heat engine. It converts a temperature difference between the head and the bulb to a pressure difference, which eventually performs mechanical work.

• Will the cycle continue if the water is removed?
• How important is the position of the pivot to the motion?
• How is the bubble related to the motion?

RGB Lights 

Turn the knobs.
Can you predict the RGB intensities required to produce a desired colour?
In which pre-determined sector?

 

Seeing Particles

Invented by Charles Wilson in 1900, the cloud chamber was the first apparatus to detect sub-atomic particles. Particles passing through it cause vapour trails in the alcohol-in-air atmosphere it contains. These trails can be almost any shape and are unpredictable. Cloud chambers are used to visualise radioactivity. This cloud chamber detects natural radiation.

The Proof Is In The Experiment

Gregor Mendel (1822–84), an Austrian Monk, worked out a system, in peas, where each characteristic is controlled by a factor we now call genes. Each gene exists in two forms, one dominant over the recessive. Each individual carries two copies of the gene. Only one copy of the dominant has to be present for its characteristic to show.

The Big Changes

Thomas Kuhn believed that science advances through revolutionary changes or paradigm shifts. New theories are needed to include newly observed phenomena.

Falsifiability

Karl Popper proposed that scientific hypotheses and theories should be falsifiable, ie contain the possibility of being proven wrong. Once a theory has been falsified, a more suitable one needs to be found. Scientists should always try to prove their theories wrong, rather than continually prove them right.

Moving Energy

The released end-ball’s energy is transferred from stationary ball to stationary ball because energy cannot be created or destroyed. The opposite end-ball moves when it receives the energy but no resistance to moving forward. This process is repeated in the reverse when the end-ball swings back. Releasing 2 or more end-balls results in the same number of balls moving off at the other end, for the same reasons. Friction and slightly different balls cause energy losses that slow and finally stop the swings.

Atomic Models

Modelling the atom began more than 2500 years ago. Less than a century ago, before scientists could split them, atoms were thought to be indivisible. Now we know that atoms are incredibly small: their radii are 30–300 trillionth (10-12) metre , and their nuclei 10,000 times smaller! An atomic nucleus contains positively charged protons, usually bound to chargeless neutrons. The atom is the smallest particle of an element.

What Is It Exactly?

Views that are not directly in front of the pointer give different readings. These are parallax errors. By aligning the pointer over its own image in the mirror, parallax is reduced.

Which Water?

Good experiments should keep all variables constant, except the one variable being tested. There should be a “control” case in which every factor is kept at a constant value against which it will be tested later. Experiments always show up more questions and therefore the need for more and better experiments to answer them.

Is this a good experimental design to show whether the animal prefers a particular type of water?

See Beyond The Naked Eye

Scientists use scanning electron microscopes to see very, very small objects, almost in 3D. It works at much higher magnifications and sees things in much greater detail than any light microscope. This is because it uses a beam of electrons which are essentially dimensionless points compared to the wavelengths of light. The electron beam scans across the object surface. The reflected electrons are captured and electronically translated into a picture which is displayed on the monitor.