Try Engineering

I found Try Engineering looking for some fun interactive games for my kids on the web. The site is for people interested in engineering careers and so has a lot of information about careers and schools.

Two tabs are of interest in our house. One is the Lesson Plans tab that has a long list of interesting engineering activities for either homeschool or co-op. You can download an 8 page pdf catalogue of all the available plans. The other is the Play Games tab. They have 4 interactive activities produced by the site--Bionic Arm Design Challenge, Questioneering, Design a Parachute, and PowerUp. They also have a good-sized list of other interesting engineering games. I showed this to Ds#2 just before he went to bed and now he can't wait to get on the computer in the morning!

BioEd Online

The latest great science web resource I found is BioEd Online and its companion site, K8 Science. The sites have news, presentations, slides, lesson plans, and teacher resources for biology. While the sites cover relatively few topics in biology, they still have a decent repository of good quality resource available for free.

The sites have a lot of information about laboratory techniques, including a sheep dissection video, measuring and counting with a light microscope, micropipetting, dilutions, and more. K8 includes some physical science topics as well. Despite their limited subject coverage, they have managed to put out quite a bit regarding embryonic stem cells; unfortunately they have no information regarding other sources of stem cells. They have a presentation on cloning, too.

Overall the sites are a great place to look for ideas or to supplement something you may be doing already.

Geminid Meteor Showers

The Geminid Meteor Showers have begun and are due to peak at 2 am on December 14th!

From Universe Today:

Occurring every year in mid-December, the Geminid meteor shower is commonly referred to as the most reliable meteor shower of the year. That is, it almost always puts on a great show!

The Geminid meteor shower is sure to be a stunning show this year, as the Moon will not be visible at night, so its glow will not impede your meteor viewing ability. In addition, the Geminids' radiant is favorably positioned for most viewers at this time of year.

Can I shake my kids out of bed at 2 am? Our homeschooling friends up the street live on the top of a treeless hill that would be perfect for viewing...

Rock and Mineral Show

As part of our geology study we went to a local rock and mineral show. It is a great opportunity to collect minerals and to see where locally people are finding them. This is our first visit to one of theses shows; someone on the AtHomeScience Yahoo group suggested this wonderful idea.

Any child that went to the show got a grab bag of various rocks, and then my kids bought a few, too. The 5 rocks along the bottom of the picture were bought while the rest came in their grab bags.

Ds#1 noticed that one dealer was selling rocks that looked very similar to one he had recently found. We knew it was an igneous rock, granite in particular. It had no pick feldspar though it can be white. The specimen is striking for the many black crystals in it. The black crystals turn out to be biotite, a type of mica; we could tell because it was easy to flake. And since the rock also has muscovite mica, it is called binary granite.

BTW, the University of Pittsburgh and Cal Poly Pomona have informative and pictorial sites for identifying igneous, metamorphic, and sedimentary rocks.

Saturday Science Challenge #13

Layers of the Earth

The earth has 3 basic layers--the crust, the mantle, and the core. Texts will emphasize the thinness of the crust. Making models is a wonderful way to demonstrate this, though I found my kids were particularly impressed by this demonstration.

The earth is not perfectly spherical, and the crust of the earth is irregular, so exact numbers are not really possible, but these are the ones we can use for this activity:

Radius = 6378 km
Distance to core edge = 2890 km
Distance to mantle edge = 35 km (from Wikipedia)

Take a measuring tape at least 6 m long; have someone hold it in place at the "center" of the "earth." First measure out to 2.73 m. Holding chalk and the edge of the tape together, draw a circle, or at least an arc; this first line is the edge of the core. Now bring the tape out to 6m and draw a second arc; this second line is the edge of the mantle. Ask your kids, "How thick is the crust in this model? How much longer do I extend the measuring tape to draw the crust?" Have them mark where they think the line would fall.

Answer: 3 cm

For advanced students, have them calculate the ratios. I choose to have the edge of the mantle to be 6 m, so how large is the full radius for the model? The actual distance from the center of the earth to the mantle's outer edge edge is 6378 km - 35 km = 6343 km. Now set up a ratio:

distance to outer mantle (6346) is to earth's radius (6378) as model distance to outer mantle (6 m) is to model radius (rm).

6346/6378 = 6/rm --> (6378)(6) = (6346)(rm) --> (6378)(6)/6346 = rm
rm = 6.03

You can set up a similar ratio to check the edge of the core.