See how light knocks electrons off a metal target, and recreate the experiment that spawned the field of quantum mechanics.

The population projections presented in this publication cover the period 30 June 2008 to 2101 for Australia and 30 June 2008 to 2056 for the states, territories, and capital cities/balances of state.

This issue contains estimates of the resident population of Australian states and territories as at 30 June of each reference year. Estimates up to 2006 are final, based on the results of the 2006 Census of Population and Housing. Estimates for June 2007 have been revised and estimates from June 2008 onwards are preliminary.

Blast a Buick out of a cannon! Learn about projectile motion by firing various objects. Set the angle, initial speed, and mass. Add air resistance. Make a game out of this simulation by trying to hit a target.

Delve into a microscopic world working with models that show how electron waves can tunnel through certain types of barriers. Learn about the novel devices and apparatuses that have been invented using this concept. Discover how tunneling makes it possible for computers to run faster and for scientists to look more deeply into the microscopic world.

How does energy flow in and out of our atmosphere? Explore how solar and infrared radiation enters and exits the atmosphere with an interactive model. Control the amounts of carbon dioxide and clouds present in the model and learn how these factors can influence global temperature. Record results using snapshots of the model in the virtual lab notebook where you can annotate your observations.

Broadcast radio waves from KPhET. Wiggle the transmitter electron manually or have it oscillate automatically. Display the field as a curve or vectors. The strip chart shows the electron positions at the transmitter and at the receiver.

Learn about different types of radiometric dating, such as carbon dating. Understand how decay and half life work to enable radiometric dating to work. Play a game that tests your ability to match the percentage of the dating element that remains to the age of the object.

Explore forces, energy and work as you push household objects up and down a ramp. Lower and raise the ramp to see how the angle of inclination affects the parallel forces acting on the file cabinet. Graphs show forces, energy and work.

Measure relative humidity in the air using a simple device made of a temperature sensor, a plastic bottle, and some clay. Electronically plot the data you collect on graphs to analyze and learn from it. Experiment with different materials and different room temperatures in order to explore what affects humidity.

Learn about the physics of resistance in a wire. Change its resistivity, length, and area to see how they affect the wire's resistance. The sizes of the symbols in the equation change along with the diagram of a wire.

How did Rutherford figure out the structure of the atom without being able to see it? Simulate the famous experiment in which he disproved the Plum Pudding model of the atom by observing alpha particles bouncing off atoms and determining that they must have a small core.

In the final lesson of the SDO curriculum, student teams collaborate to design and present their three Solar Module activities as part of their 3-D Solar Exhibit summative assessment.

Use a virtual scanning tunneling microscope (STM) to observe electron behavior in an atomic-scale world. Walk through the principles of this technology step-by-step. First learn how the STM works. Then try it yourself! Use a virtual STM to manipulate individual atoms by scanning for, picking up, and moving electrons. Finally, explore the advantages and disadvantages of the two modes of an STM: the constant-height mode and the constant-current mode.

This lesson uses NASA satellite data to correlate cloud cover over Africa to the solar declination. The student will access NASA data using the MY NASA DATA Live Access Server and import the data into Excel spreadsheet software. Students will use NASA satellite data to correlate cloud cover over Africa to the solar declination.

Explore your own straight-line motion using a motion sensor to generate distance versus time graphs of your own motion. Learn how changes in speed and direction affect the graph, and gain an understanding of how motion can be represented on a graph.

Semiconductors are the materials that make modern electronics work. Learn about the basic properties of intrinsic and extrinsic or 'doped' semiconductors with several visualizations. Turn a silicon crystal into an insulator or a conductor, create a depletion region between semiconductors, and explore probability waves of an electron in this interactive activity.

Dope the semiconductor to create a diode. Watch the electrons change position and energy.

Why do the lights turn on in a room as soon as you flip a switch? Flip the switch and electrons slowly creep along a wire. The light turns on when the signal reaches it.

Investigate what makes something soluble by exploring the effects of intermolecular attractions and what properties are necessary in a solution to overcome them. Interactive models simulate the process of dissolution, allowing you to experiment with how external factors, such as heat, can affect a substance's solubility.