Secular Science Resources for Homeschoolers


February 2016

Big History 023 – Defenses

imageWe started Threshold 7 of the Big History Project this week (well, maybe a bit last week).  Theshold 7 is Agriculture, when populations exceeded the limits that hunting and gathering could support we had to start growing our own food and domesticating animals, this allowed the populations to continue to grow.   For class I used another of the It’s About Time archaeology lessons, The Archaeology of Defence,  and their slide show on Irish Castles thru the ages.  I made a slideshow from the Archaeology of Defense material, talking about the first evidence of people protecting their homes with fosse (fancy word for ditch), banks and palisades (pointy sticks) and the different ways those things could be used. We also talked about how we defend ourselves and our stuff nowadays, including the use of military to protect our country.

The slide show of castles continued to stress the different defensive structures like draw bridges, murder holes, arrow loops, etc. It also discussed how castles changed through the ages as the plague hit, the developement of cannon, etc.  There are a few worksheets at the end of each lesson that the kids did at the end of class.  The first one involved looking at pictures of different homes/villages from different time periods and listing the form, fabric (what is it made of) and function of each defensive structure.  Then they had to point out and label the defensive structures on an enclosed castle and a tower house.  These sheets were put in their notebooks.

Castle stairsThe most interesting thing I learned from this lesson was that the narrow spiral stairs in castles are always (??) clockwise so that the defender on the top of the stair has the advantage, assuming he’s right handed, since he will be able to freely swing his sword, while an attacker coming up the stairs would not be able to do much at all with his right arm.  Guess you need to send the lefties up the stairwell in an attack.

For homework I asked the kids to build their own castle or tower house in Minecraft or with real legos if they preferred.  They could also just draw one if they like.  However they build it, I want them to put in some of the defensive structures we learned about.




Physics 023 – Atoms

Chapter 26 of Light & Matter discusses the ground breaking experiments that gave us our present model of the atom so we spent a lot of time in class watching videos of the history of atomic physics. Starting of course with Crash Course Chemistry: The periodic table.

And then another Hank Green video: SciShow Great Minds: Marie Curie


Then we moved on to Tyler DeWitt’s videos.  I really like his style of teaching with the white board and props that he makes, but still being able to see him talking in the upper right hand corner.  He has an entire chemistry course on youtube and its worth checking out.

After the videos we gathered around a mini cloud chamber I had made out a petri dish and watched atomic particles leave little trails in the alcohol mist.  This video is actually from when we did this a few years ago, but its the same set up.

The petri dish has black construction paper on the bottom and felt around the circumference (inside).  Soak  the felt with isopropyl alcohol (92% if you can find it) then put the lid on the petri dish and set it on a block of dry ice.  Here,, are instructions for a bigger cloud chamber and some information on what you’re seeing. I actually have a small piece of slightly radioactive pitchblend that I bought at a rock and mineral show that is a nice source of alpha decay.


Big History 022 – Language

We’re still  in Unit 6:  Collective Learning and a big part of collective learning is communicating and teaching one another via language, so today I talked about the origin of language and writing.  I found a great website by the University of Hawaii on one of their courses: An Introduction to the Study of Languages and made a slideshow based on the first few lessons.  I also showed a number of videos on youtube about the origin of written language since we have a lot more data on that then we do on the origin of spoken language.

This is an interesting series of short videos, Thoth’s Pill, about the history of writing.   I showed the first 3 but actually watched 5 or 6 myself.  You can also watch the whole series in one long episode.  If you’re studying Japanese or Chinese I suggest watching these, it had a lot of examples that explained where certain kanji come from.

And lastly, I showed a Ted-Ed video on How languages evolve.

For the activity, I had printed out the Sumerian cuneiform alphabet and had the kids put it in their notebooks and then write their initials or first name in their books.  Then they had to make up their own symbols for the numbers 1 – 9 and for three things they wanted to barter with.  I got this activity from the Middle Tennessee State University website on Teaching with Primary Sources.


Physics 022 – Electromagnetism

Today we played with electromagnets.  I had already set up a snap circuits demo with a solenoid and showed that when the current was turned on the iron core was sucked into the solenoid.  Then I had the students make their own solenoid with wire, a large iron nail and various batteries.  I challenged them to make a better solenoid – who can pick up the most paper clips with their electromagnet.  We talked about how more turns would make it stronger or more current (more batteries).  I also have  a Texas Instrument sensor that connects to my iPad via bluetooth and it can measure the magnetic field directly.  The largest reading we got was around 0.9mT.


The students also made little coils that will keep spinning when placed over a magent. These are a lot of fun and the students always enjoy making these.  Its helps to have strong magnets, but you can make it work with most regular magnets and a bit of magnet wire.

One student made a large coil and hooked it up to an ammeter, but NO BATTERIES.  Obviously no current was going through the coil, but when you move a magnet in and out of the coil it induces a current in the circuit.  We were able to get close to 1mA by dropping neodynium magnets through the coil.

Speaking of neodynium magnets… I want to do this demo so bad.


Big History 021 – Artifacts

The archaeology lesson that I used last week went so well that I decided to use another from It’s About Time. This lesson was on Lifestyle and artifacts and what information we can gather about a culture/people from the things that we find.  As before I took the curriculum and made a slideshow from the material.  It was mainly about  lifestyle: how we eat, sleep, dress, education, recreation and the artifacts that we use to do those things: fork, knife, plates for eating for example.  Then we looked at a regular pen and tried to think of all the things we could learn from it…. if people had pens, they were literate – could read and write, if there were a lot of pens, it might be a school and the number of pens would give us an idea on the number of students.  Is the pen inscribed? Does it tell where it was made?  If made in a foreign country then we know the people take part in international trade…. and so on.   The other thing I put in my slide show is a few pages from one of my favorite books: 51PGxOVSKnL._SX374_BO1,204,203,200_ Motel of the Mysteries by David Macaulay.  This book takes place in the future when a man happens to fall into a hotel hallway that was buried in debris.  He excavates the tomb (hotel room) and discovers an inner tomb (bathroom) with another body placed in a white sarcophagus (tub)…. and so on. Its a very entertaining book, poking fun at our modern day artifacts and how people might interpret them in the future.

The activity this week was mending pottery.  My boys and I decorated some cheap terracotta pots from Walmart ($0.78 a piece) with some sharpies and then broke them into bits before class.  As the kids arrived for class I had them pull one shard from a paper bag (it contained one shard from each pot). IMG_2021 They then had to go through the 4 containers of pot shards and try to find all the pieces to their pot.  Students worked in pairs, mostly siblings so they could take their pot home when they were done.  Once they had all the pieces they started taping them together.  IMG_2024Real archaeologist do it this way as well, because you want to make sure you have all the pieces you can find and know where they go before you start using glue.  The kids had a lot of fun with this activity.


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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 (