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# homeschoolsciencegeek

### field trip

Over the weekend, my students and I took a private tour of the Lick Observatory on Mount Hamilton.  We got to see a couple different telescopes, hear about the research they’re involved in, and learned about the life of James Lick.  Unfortunately, clouds were rolling in and the humidity was too high to use the big telescope for viewing (don’t want condensation on the optics).   But I was able to set up  my  telescope (outside the dome in the photo above) so everyone got to see Saturn and Jupiter before we had to head down the mountain.   It was actually pretty dark when the above photo was taken, that is the Milky Way appearing vertically by the dome and an airplane trail crossing over the dome.  I highly recommend taking a fieldtrip to a local observatory if you have one in your area.

Instead of lecturing on the force of gravity this week, I had the high school students use a physics simulator at the Physics Classroom website to figure out for themselves how the force of gravity depends on the distance between objects and the mass of the objects.  They have an activity sheet you can download that steps you through this activity.  By moving the sliders you can change the mass of the moon and the planet, or you can move the moon closer or farther from the planet. This interactive works on smart phones and tablets as well as laptops.

Students set the masses and then recorded the Force at different distances.  The handout does not require a graph, but I had them make a graph of their data.  One student used a graphing calculator to do a best fit to his data and found that the force depends on 1 over the distance squared.

Students then kept the distance fixed and changed one of the masses and found that the force of gravity depends linearly on mass.

I also set up a demo that demonstrates how massive objects curve space-time by stretching a large piece of spandex-like fabric over a hula-hoop and then balancing it on chairs to keep it level.  When a large marble is place in the center the fabric stretches and curves the fabric (space-time)

The larger the mass, the more the fabric is curved.  Students took turns making smaller marbles orbit the large marble.  We also increased the ‘mass’ of the ‘star’ in the middle by pulling down on it from below.   I also talked about LIGO and how they’re measuring the vibrations on the fabric of space-time, which are gravitational waves.  Here are videos on the subject.

Students were to read Chapter 5 Gravity in Foundation of Astronomy and watch the following Crash Course Astronomy this week.

We also did the How Do We Know What the Milky Way Looks Like? Activity from the Big History Project Unit 2 under Other Material.  Since we can leave the Milky Way galaxy, the images that we see of it are not photographs but artists renderings based on what we can infer from our observations.  Students were asked to pretend that they had never seen the outside of the building we were in and to write down a description of the house using only information they could gather from inside.  They also had to write down what they could tell about about an ancient group of people from just a few photos of archeaological evidence.

The middle school class did the same activity sheet on gravity using the website but I started the class with a presentation on Newton’s Laws, the difference between speed and velocity, acceleration, forces and gravity.  I skipped the presentation with the high school class since many of them had taken physics with me already.  I did not require the middle school students to graph their data, but sketched the graphs on the white board.  We also did the BHP How Do We Know What the Milky Way Looks Like? activity and played with the fabric of space-time.

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This week both classes met at a local park for another Ranger led class.  Ranger Amy started with a discussion of water sheds, where the water in the stream comes from and where it ends up.  She asked the students what kinds of things should we look at to see if the stream is healthy?

After walking down to the stream students were divided into two groups and given a clip board with some data sheets to fill out.  First they recorded their location (GPS coordinates) and the date/time.  Students were given thermometers to measure the temperature of the air and the stream.  They also had to look around for possible sources of pollution that could end up in the stream.

We also measured the oxygen level (darker blue means higher oxygen level – healthier stream) in the water and used 9 in 1 water testing strips (which are now sold as 10 in 1) to measure pH, nitrates, nitrites, copper, lead, and more.  Students gathered water samples in small containers, dunked the strips in their samples and compared their results to key.

Lastly, Ranger Amy handed each student a strainer and they spread out around and in the stream to scoop up critters. We recorded the number of each species that was caught, mosquito larvae, water striders, mayfly nymphs, snails, etc.  Here are some photos of our finds.

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Both my classes went on a wildflower hike with a local ranger today.  We started at a Native Garden and students were given a list of 10 native plants to locate in the garden and then pick one to sketch.  We then walked 2 miles into the park looking for the plants we had seen at the Native Garden.  Ranger Amy gave us additional information on the plants and history of the park as we walked.  She also discussed native versus non-native plants, including Eucalyptus trees, which can be found throughout the park and our town. We also saw a coyote, a couple of deer, turtles and tracks in the mud from a skunk. Here are some photos from our adventure.

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I highly recommend contacting your local parks department and making connections with the rangers. They enjoy having the kids to the park and the cost for a ranger-led program is very reasonable. High School students were asked to read the chapters in their textbooks on Plant Diversity this week and watch

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This week both my physics classes went to the Tech Museum in San Jose for a class on roller coasters and to check out the Body Worlds Decoded exhibit.  The class started with a short lecture on roller coasters with a lot of class participation and then students had 10 minutes to build a short roller coaster.  After some more discussion on roller coasters and energy the students were asked to build roller coasters with a loop!  If they succeeded  with time to spare they were given a challenge card (2 loops for example).  As you can see in the photos, this was done with pretty inexpensive equipment,  foam hose insulation cut in half for tracks and whatever building toys (tinker toys in this case) you might have, masking tape and a marble.  Classes like these at museums are great, I’ve never been disappointed.  The Tech Museum field trips are a great deal, only \$5 per kid and chaperones were free, we got the 90 minute class, free IMAX film and got to wander around the museum afterwards.

The Body Worlds exhibit was pretty cool as well, may have to go back next year when we’re doing biology since I believe its going to become a permanent exhibit.

HOLLYWOOD ( and all that )

hanging out and hanging on in life and the movies (listening to great music)

Learn from Yesterday, live for today, hope for tomorrow. The important thing is not stop questioning ~Albert Einstein

graph paper diaries

because some of us need a few more lines to keep everything straight

Evan's Space

Wonders of Physics

Gas station without pumps

musings on life as a university professor

George Lakoff

George Lakoff has retired as Distinguished Professor of Cognitive Science and Linguistics at the University of California at Berkeley. He is now Director of the Center for the Neural Mind & Society (cnms.berkeley.edu).