Backyard Ballistics

When I was planning for this school year I asked the boys what they are most interested in. They both asserted that they would like to do more science, with more experiments, and more blowing things up. Not long after that I very fortuitously stumbled upon an excellent book, Backyard Ballistics, by William Gurstelle. Not only does Gurstelle explain in recipe fashion how to build such gems as "Cincinnati Fire Kites," and "Tennis Ball Mortars," the book succinctly explains the physics behind each fulfilling explosion.

As a bonus, each chapter highlights a famous scientist and his resume along with some very interesting history. This afternoon we read about Alfred Nobel, his invention of Dynamite, and how his subsequent concern regarding the danger of his invention directed him to the creation of a foundation whose goal is the advancement of peace and science, hence Nobel Prizes. My other major reason for endorsing this book is that I can confidently turn nearly 100% of this subject, save for a little planning, over to Johan.

This weekend, with big help from Johan the boys built a potato cannon. Here they are this morning; getting ready to show me what it can do. Yes, they are wearing pants and sweatshirts in early October, yes it did snow a little this weekend, and yes I am very, very sad to say farewell to the warm days of summer. I am feeling a little slighted right now, I am pretty sure we have just skipped fall. Yesterday afternoon when we checked on our garden, many of the big green pumpkin vines were withered and black.



Here is a shot of them building the contraption after soccer on Saturday.

The joints had to cure overnight before the finishing touches could be made and the project could be tested. It is really remarkable what a little aerosol hairspray as a propellant can do.

Explosions aren't really my idea of a good time... But the look on the boys faces when they came dashing in to ask me if I had heard the bang was priceless. Unfortunately I did not have my camera at that moment. And from the home school side, there is a whole lot of science wrapped up in all of this fun.

The potato cannon effectively demonstrates parts of all three of Isaac Newton's three laws of motion. In case you are curious:

1. The first law of motion tells us that after the potato is launched, it will continue to shoot forward until another force stops it. (In our case that is the large hill behind our house.)
2. The thunk of the potato against the hill is equal to the mass of the potato multiplied by the acceleration of the potato. (We're going to trust Isaac on this and save this math for six or seven more years.)
3. When the potato is fired from the cannon, an equal and opposite reaction is exerted on the support structure holding the cannon. (For us, it is Johan.)

Up next, "The Paper Match Rocket."

Government Grrrrrrrr...

Not far from our home there is a great little park. There is a nice playground, and a bike trail that goes right past it. Big trees provide shade in the summer. But this park has a major flaw, sadly it is encumbered by the fact that it falls under the jurisdiction of the government of the United States of America. Inside this locked building there are toilets, working toilets, with plumbing and running water. I know this because recently one of the mom's on my soccer team gained access to the building and flushed.... But alas, this building is not ADA compliant, as a result the law requires that this building be locked.



While the above building remains securely locked, the city parks department has made this fine accessible unit available.



For the scores of soccer and football practices that are held weekly at this park, there is a single handicapped accessible port-a-potty. I coach two soccer teams, a total of four weekly practices, at this park, for these kids, there is no place to wash their hands. But at least everything is perfectly fair??? Grrrrrrrrrr....

EGGcellent!!!

I am so, so impressed with our chickens. Look what they did in just two days! To be sure, the turkey and the ducks can claim some credit for the larger eggs, but to me this is absolutely remarkable. Yesterday the boys collected 37 eggs! All new since Monday.



Happily I can also report that consumption of these eggs is very good for you. So to our chickens I say THANK YOU, and keep up the good work.

In case you are interested in some of the science behind our desire to keep chickens, I'll quote at length from Nourishing Traditions by Sally Fallon:

Shunned for several decades by orthodox practitioners as a high-cholesterol food wrongly believed to cause coronary heart disease, the egg is making the comeback it deserves....Properly produced eggs are rich in just about every nutrient we have yet discovered, especially fat-soluble vitamins A and D....Eggs from pasture fed hens have nutritional qualities that are far superior to those of battery-raised eggs and even many so-called 'free range' eggs. In particular,they contain a better fatty acid profile, one in which the omega-3 and omega-6 fatty acids exist in an almost one-to-one ratio; but in eggs from chickens fed only grains, the omega-6 content can be as much as 19 times greater than all important unsaturated omega-3. Other very-long chain and highly unsaturated
fatty acids-necessary for the development of the brain-are found in properly produced eggs but are almost wholly absent in most commercial eggs.