I follow a lot of science related organizations on facebook and this game called Quantum Moves by Aarhus University popped up on my feed this weekend. Its part of Scienceathome.org where apparently they are designing games/apps for the public to play and then using the results of the game play to design better experiments in the lab. The Quantum Moves games displays an atom as its wavefunction stuck in a potential well, and you have to move the potential well around to move the atom to a desired location. It starts off easy enough but the problems get harder and harder as you go. I think this is a great game for physics students since its kind of hard to play with wavefunctions in a highschool lab.
Today was very similar to last weeks class but instead of having the cart move at constant velocity, we wanted constant acceleration. Following in the steps of Galileo we inclined the track by placing a few blocks under one end, giving an angle of only a few degrees. Data was taken with the Video Physics app and then moved to the Graphical Analysis app by Vernier. The Graphical Analysis app gives you more control on how your graph looks, and it can perform a best fit of your data (find the slope of the best line that describes your data). We calculated slopes by hand last week but this time I let them use the app. Everyone had very nice linear graphs of velocity as a function of time (blue line below). We took data as the cart traveled up the track, slowing down, until it stops and then accelerates down the track. You can see on the photo above the red data points marking the position of the cart for each time step. Just by looking at the smaller distances between the dots at the high end of the track you know the cart was moving slower. Before the kids took data they made predictions of what they thought the position vs time, velocity vs time and acceleration vs time graphs would look like. Most of them knew the velocity vs time graph would be linear and the acceleration vs time graph would be a horizontal line (constant!) but it can be hard to visual what that means for the position vs time graph. By taking data with the cart going in two directions, I’m hoping their data helped get it across that the acceleration was the same the entire time even though the velocity changed direction (went from negative velocity to positive velocity – increasing at a constant rate). When they had their graphs printed out and their acceleration reported with correct units and uncertainty, I had them look back at their graph predictions and see how they did.
When we were done with the lab, I introduced a bit of a calculus, explaining how finding the slope of a line is the same as taking a derivative in calculus. None of these students are in calculus though a few are starting pre-cal, so we won’t be using calculus in this class, but I want them to see how its used so when they do start seeing it in math, they’ll understand why its useful. I also worked some problems in class and tried to demonstrate that when working on physics problems, you start by sketching the problem… stick figures come in to play a lot, and by writing down all the things you do know and what you are looking for. For example, if the problem says you drop a pebble, then you know the initial velocity is zero and its going to be accelerating downward. If the problem says the pebble is thrown, then you know the initial velocity is nonzero.
Next week we cover Chapter 4 – forces. The experiment we did today could also be done with a marble on a track, you don’t need the air track to do this.
I wouldn’t have bought this air track for just my kids, its too expensive. But one of the advantages of doing science with a group is splitting the cost of equipment. Since we’l be doing honors (AP) level physics this year I thought this was a worthy investment. We’l probably use it for 6 or 7 weeks of mechanics labs – motion at constant velocity, constant acceleration, elastic and inelastic collisions, conservation of momentum and simple harmonic motion (you can hook up two spring to a cart and watch it oscillate back and forth on the track). We’l use the Video Physics iPad app to record and analyze the motion.
My younger son wanted to bring it out to show his older brother how it worked since he’d been at camp when it arrived. I think he’s a bit disappointed we’re not using it in his science class this year, but he can be my tester and test out the labs before the physics class or even participate in the class if he wants. But as we were setting it up he asked what would happen if we turned on the air source when it wasn’t attached and we both got the same idea at the same time….let’s levitate a ball! He tried a ping pong ball first and it went flying across the house! Thinking about the exhibit at the Exploratorium with the beach ball balancing in the jet of air, I figured we needed a ball a bit bigger than our hose so the air would curve around the ball and keep it in place. The small earth ball worked perfectly and if you give it a spin it is quite stable! I hadn’t even thought about what I could do with the air source by itself so now I can add a few labs to our schedule for fluid dynamics and air pressure.
One of my favorite pieces of science equipment is our microscope. I bought the 3088F-I microscope from Great Scopes over 5 years ago and it was worth every penny. The grand total was under $300 back in 2010 and it doesn’t look their prices have changed. If you contact them and let them know you are a homeschooler they will give you a 10% discount (at least they used to). Make sure you get the mechanical stage on the microscope so you can move the slide around by tiny amounts. There’s not much point in getting a microscope with out a moving stage. This scope only lights up the slide from below, but you can turn that light off and shine a flash light on your slide from above and get great real color views like the photo to the right of mold growing on a strawberry. This is the gray fuzzy stuff you see on rotting strawberries, its actually quite beautiful!
When we first got the microscope, I taught a short summer class where we did a microscope unit study called Microscope Adventure by Kym Wright. Its only $15.95 for the ebook (I’m a big fan of ebooks since it allows me to print out the worksheets for both of my boys and not have to scan/copy them). This is a great unit study and it is secular (not all of her unit studies are secular). Microscope Adventures teaches you the parts of the microscope, how to make slides, and clean up afterward.
The different labs include collecting dust and fibers from around the house, fungus, leaves and pollen from outside; skin cells and hair off your body and of course dead bugs from window sills. She also includes a nice list of books for supplemental reading. I highly recommend going through at least some of this unit study when you first get your microscope. Kym Wright’s Botany Adventure! was also excellent – we did a whole year on botany at my son’s request. The only other unit study I have purchased from her was Bird Adventure! which was NOT secular and we ended up not using.
A set of prepared slides is also nice to have because its really hard to make thin slices of some things and it might be hard to find a volunteer to give lung tissue! We’ve been collecting sets of slides for 5 years and now have a plastic shoe box full: botany slides, human
anatomy, marine life, reproduction (mitosis and meiosis), etc. They can be pretty expensive so I usually wait til I see them on sale. Home Science Tools has some nice sets and you can buy blank slides and cover slips from them as well. I also recommend buying at least one box of concave slides for looking at pond water. I also traded science supplies with another homeschool science teacher one year. She had a great set of beakers, graduated cylinders, and chemicals that I borrowed for Chemistry and she borrowed a bunch of my slides and books for a botany class. So if you’re looking for science equipment its worth asking your local homeschool group if you anyone has some you can borrow.
The other purchase you should make if you buy a microscope is a smart phone adapter. I got the Carson HookUpz Universal Adapter last year and we used it a lot in the biology class. I can also use it on my telescope and binoculars. It comes with a nice storage case. All the microscope photos on this page were taken with my iPhone 5 and the Carson adapter. I usually take my case off to use the adapter because it can’t get a good grip on my bumpy case.
It doesn’t happen as much now, but my boys would frequently find something in the yard, a dead bug, a leaf, flower parts and ask to look at it under the microscope. They’re just a great tool to have around and can really spark an interest in science.
Secularhomeschool.com led me to a post about science youtube channels from The Big Green Chair, this morning. They had 2 channels I hadn’t heard of before, Sixty Symbols which looks like it should be great for our physics class this year and STEMbite which could be useful for the middle school class. Since I love finding good YouTube channels, I thought I would share some of our science favorites and I’l be honest, my kids showed me most of these.
- Crash Course – we love these, all of them. Granted some of them can go over our head but they are still entertaining, the kids enjoy watching them and always get something out of it. The Astronomy Crash Course we’re watching now is fine for middle school and up, while the Biology and Chemistry are upper level high school – though they can still be worth watching.
- Veritasium – I love this guy. I’m pretty sure my kids brought me to this channel. Very entertaining and interesting videos on a wide range of topics. I showed Why Women Are Stripey, about DNA and sex chromosomes, in biology class last year.
- SciShow – another great channel from the Green brothers (Crash Course). I particularly like their Great Minds videos. A good portion of these feature famous women scientists like Rosalind Franklin, Goodall, Fossey and Curie to name a few. They also covered current events and controversies. The have a second channel called Sci Show Space that’s obviously space related videos.
- Minute Physics – great explanations for physics concepts like, “What is Gravity?”, “What is Dark Matter?”, “What is Wave/Particle Duality?”. And I love their music video, Astronomically Correct Twinkle Twinkle.
- In a Nutshell – Kurzgesagt, has a unique animation style that I really like and it usually gets the point across nicely. A lot of technology (fracking, nuclear energy) and astronomy/astrophysics (big bang, solar system, dark energy) topics, along with a few on human immune system and evolution.
- The Royal Institution of Great Britain has amazing videos. The series of Christmas lectures are geared towards family and highly entertaining – the best demos. These are long, a bit over an hour, and when I tried to show just the first 30 minutes in my class, they mutinied and insisted on watching the whole video. These are really the cream of the crop. The Science of Fireworks! and Chemical Curiosities: Surprising Science and Dramatic Demonstrations are two of our favorite.
- Science with Tyler DeWitt. I used his videos the last time we did chemistry and will probably using some of them in our physics class this year. He says the videos are aimed for kids in high school chemistry aiming for the SAT/AP exams. There are a lot of channels where teachers are making videos like this, but I find most of them hard to watch, but Tyler DeWitt keeps my attention and I like his format – two views, you can see him talking in a small window but the main window is a white board where you can see what he’s writing.
- BBC Earth Unplugged has a lot of slow motion videos of animals in flight, swimming and time lapse movies of decomposition, along with regular videos explaining topics such as, “How does a Peacock Feather Shimmer?”, great for Biology.
- Science! with the Amoeba Sisters was a big hit with my middle school biology class last year. There’s over 30 short low-tech videos on biology topics. They aren’t quite animated, just a series of funny cartoon images to go along with the audio but the kids liked them.
- And I can’t leave out True Facts by zefrank1. You might want to screen these first, some are better for older kids. These are very funny and have some very interesting facts about animals that you probably didn’t know.