## Physics at Home Archive - Page 3

Fractals Unit: Iterative Formation - Aug 2, 2011

You don't have to graph complicated equations to create your own fractal--you can create your own on plain paper by following the directions at Fractals Unit: Iterative Formation. There are several simple patterns you can try, such as the Von Koch curve.

For those who do want to graph complicated equations, there are many free fractal-generating programs available online for advanced users, such as Apophysis.

Reduced Gravity Demonstrator - Jul 1, 2011

To find out how to build a drop tower to investigate apparent weightlessness, see the NASA site Reduced Gravity Demonstrator. Be sure to have adult help if you try this. (BTW, it's a challenging and expensive project.)

Also, check out this NASA video to see astronaut David Scott drop a hammer and a feather on the moon.

This issue was updated on 07/11/2011.

Double Pendulum Model - Jun 8, 2011

For a simulation of the double pendulum, click here; then, in the new window, click on "download ejs mech..." and then click on the "Double Pendulum" window. Get the double pendulum started by clicking and dragging the two masses to different heights.

Calculate Your Radiation Dose - May 12, 2011

Visit Calculate Your Radiation Dose to calculate your annual radiation dose, and see this EPA page on health effects to learn about normal doses of radiation. To find out more about natural sources of radiation, visit Sources of Radiation Natural Background Sources by the Nuclear Regulatory Commission (and don't miss the two links at the bottom). Also, food, especially the banana, is slightly radioactive, as described in this short Discover Magazine piece.

Light: The Physics of Art and Visual Perception - Apr 12, 2011

A diffracting grating shows the colors within light like a prism. The tiny slits that make up the grating bend entering light into different directions according to their wavelength, which shows the different colors.

In this activity you can look at the spectrum of light from a candle. Make sure to have adult supervision while working with flames. Diffracting gratings can be purchased cheaply online. Also, you can use your grating to investigate light produced by other light sources in your house.

Balloon Analogy in Cosmology - Feb 1, 2011

Quasars are the most distant objects we can see from Earth. Their light reaches us from billions of years in the past. Astronomers know how far they really are from us because the light we see is dramatically redshifted, meaning they are moving away from us astonishingly fast. See the Balloon Analogy in Cosmology to learn more about the expansion of the universe and how astronomers use redshift to measure distances in space. Find out how you can paste galaxies on a balloon and make a model of how the universe expands.

Doppler Physlet - Dec 1, 2010

Try this Physlet simulation from Davidson College to investigate the shockwaves and Doppler effect produced by objects moving at various speeds--in particular, at speeds below and above the speed of sound.

Laser Applications - Nov 1, 2010

Lasers are everywhere, from the supermarket to your CD player. Learn about even more applications at Laser Applications, and be sure to check out the Laserfest website for more information.

Near-Earth Object Program - Oct 16, 2010

Asteroids are usually shown between the orbits of Mars and Jupiter, but they also swing in as far as Earth's orbit, and frequently. At the time of this writing, astronomers have identified 1156 potentially hazardous asteroids, so-called because of their large size and close projected approach to Earth.

- To learn more about asteroid detection and impact risk, check out the NASA's Near-Earth Object Program.
- For daily updates about the Earth's local environment, read Spaceweather.com.

U.S. Department of Energy: Energy Efficiency & Renewable Energy - Oct 1, 2010

Beyond the search for renewable energy sources, a complementary approach is to save energy by using it more efficiently. See this California state government website to find out how changes to your home and your lifestyle can help. To learn more, visit U.S. Department of Energy: Energy Efficiency & Renewable Energy and click on the links under "Renewable Energy" and "Energy Efficiency" on the right.