Physics

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Physics
SC1301~Physics

Physics Practical 1

AIR NEEDS SPACE TOO

Where we get to look at the weather and how hot air balloons and space rockets work

Air is made up of molecules, and because it is a gas, we know that the molecules are free to move about and bump into each other. If you put some air into a container then the molecules also bump into the walls.

There is air all around you right now. Can you feel the molecules of air bumping into you? Well actually, you can’t feel them because you are so accustomed to them. If you were pushed out of a space rocket without your space-suit properly done up then there would be no air molecules pushing in on the outside of your skin and you would expand in a fairly unattractive way – but that experiment has not yet been done.

In fact, the column of air molecules above you creates a pressure on your body all the time – and we call that ATMOSPHERIC PRESSURE. When you go up in a jet aircraft (to about 8 to 10 kilometres high) there are not many air molecules left and the pressure outside is very low indeed. This is why we have to pressurise the aircraft cabin. If you dive to a depth of about 10 metres, the pressure of water plus air is equivalent to 2X atmospheric pressure.

Part 1. THE MAGIC GLASS

Part 2. THE SIPHON – HOW TO MAKE WATER RUN UP HILL

Part 3. BUOYANCY, THE TITANIC AND HOT AIR BALLOONS

Part 4. A GAS ROCKET

Physics Practical 2

LIGHT – WHICH TRAVELS IN STRAIGHT LINES

but hey! We can bend it

I was impressed once by a human-interest news item about an elderly near-blind gentleman who was living in solitude on one of the small islands east of Auckland, New Zealand. When asked how he managed with poor eyesight he pointed to the sky and said, " I can still see the sun; and it is 93 million miles away."

In this laboratory session, we will look at some of the properties of light; and at some of the science-based illusions.

Part 1. LIGHT TRAVELS IN STRAIGHT LINES

Part 2. FLAT MIRRORS – WHERE WE TURN LIGHT RAYS AROUND

Part 3. LENSES – WHERE WE BEND LIGHT IN A CONTROLLED WAY

Physics Practical 3

ELECTRICITY – THE STUFF OF MODERN TECHNOLOGY

where we get to look at the most important bits of Physics behind our technological life-style

I counted the number of electric motors in my house and got 35; and I almost certainly missed some. My house is not particularly high on the technology front; it is an ordinary Australian middle-class house. Electric circuits and associated things like motors and integrated circuit chips form a huge part of our Gross National Product and impact on our everyday living. In this session we will get some basic understanding of electricity (and its life companion magnetism) and find out how some of the things work. This is a fascinating area of Physics which has a sort of a membership fee, where you have to know some of the basic concepts, and also some of the superficial jargon, before you can start to get the real benefits and enjoyment. At the end of this session and the accompanying lectures, you will have your membership credentials.

Electricity is based on the simple idea that there are three types of particles in nature (and we are talking about sub-atomic particles here): negatively charged; positively charged; and neutral. The atom has a positive nucleus and a surrounding cloud of negative electrons. It turns out that it is quite easy to separate a few of the outside electrons from most atoms. You can do this by heating up a piece of metal, or by rubbing it; in cumulus clouds the vigorous winds cause electric charge separation from ice particles and we get the dramatic phenomenon of lightning. For a metal, like copper or aluminium, you can easily lift electrons out just like scooping a cup of water from a pond. To bring electric power to your house the Power Company simply scoops up metallic electrons and pumps them down the wires.

Water/Electricity Analogy

Part 1. AN ELECTRIC CIRCUIT

Part 2. THE MULTIMETER

Part 3. MAGNETS

Part 4. ELECTROMAGNETS

Part 5. THE ELECTRIC MOTOR

Electric Motor Schematic

PLEASE READ THE SAFETY PAGE

	Part 1. AN ELECTRIC CIRCUIT
	Part 2. THE MULTIMETER
	Part 3. MAGNETS
	Part 4. ELECTROMAGNETS
	Part 5. THE ELECTRIC MOTOR