Forum Replies Created
Thank you for your question Tilden. A video animation showing how a car engine works can be seen here: https://www.youtube.com/watch?v=V-z-R8Mv_HM
Following the energy, it starts with potential energy tied up in the nature of the fuel. An air-fuel mixture is drawn into the cylinder and compressed with the upstroke of the piston. With ignition (via the spark) the fuel burns, i.e., releases its potential energy (explosively) mostly as heat. The heat causes great expansion of the already compressed air pushing the piston down with great force. This is the transfer to heat energy to movement energy. This movement energy is transferred from the piston to the crankshaft to the transmission, to the wheels of car and finally the car’s motion.
I am sorry to say that the ebook version is not printable. This is the publisher’s decision. I think you can understand why. I have no way of changing that. Again sorry.
Thanks for your question.
Think of calories as a total amount, and temperature as a “rate of flow”. For example, consider roasting a chicken. Suppose it takes one hour at 350 degrees. Temperature is obviously the 350 degrees, but that might go on for any length of time. A measure of calories would include the time, that is the total amount of heat expended by the oven to keep it at 350 degrees for one hour.
To use an analogy, think of heat as water flowing from a faucet. Temperature is analogous to the rate of flow. Calories are analogous to the total amount of water drawn.
I hope this helps. Please ask further as you wish.
Dr. Bernie Nebel
There are basic concepts presented in Volume I that public shooled kids may have missed, and later lessons depend on having a grasp of these concepts. Therefore, yes, I do recommend starting with Volume I. However, you can just review a lesson by asking/discussing items in the “Practices” section of the lesson. Only go further where you discover gaps. Of course you can make this process age-appropriate. Good luck. Please let us know how it goes.
Hands-on lessons are especially developed so that things you need will be items you probably have around the house or can easily purchase at a supermarket of office supply store. (Peruse the lists given here.) When you get to Volume II, a microscope and balance will be required. (see specifications in Volume II, 2 ed, Appendix 5 (page 435).
Lessons in Volumes II and III build on what is presented in Volume I. Therefore, I recommend that all your kids start with Volume I. Older kids can go much more deeply while younger ones still get the concept.
Thank you for your question. It is not all silly. You have a valid point. I was thinking of air as “atmosphere”, which existed on Earth well before living things, and therefore, “natural earth”. To be sure, plants have altered the atmosphere by providing more oxygen, but oxygen is inorganic; it did exist before life although not in as large amounts. But another argument comes into the picture.
Your question has caused me to think about it more myself, and I believe that therein is the answer. A key reason for making and putting things into categories, as pointed out in the lesson, is to help us organize and pursue our thinking regarding a topic. Here, we are having kids look at the entire world and it serves their comprehension to separate it into the categories. Of course, nature “feels” no obligation to fit neatly into our human-conceived categories.
We begin to see aspects that don’t fit clearly into the categories we have created. From this point of view, it should go here; from that point of view it should go there. Maybe there should be another category. But, would we engage in such thinking at all if we had not created the categories in the first place? In short, one may take exception with certain aspects, but this is because the process has stimulated thinking, and thinking stimulates learning.
Please ask further questions.
Thank you for catching this, Tom. It amazing things can slip by.
Thank you for your questions. The only major thing you need in addition to a compound microscope is a triple beam balance. Other things you will need can be picked up a local store as you need them. Sorry, I don’t have a complete materials list for Volume II. However, I think someone in the BFSU Facebook group made one. The BFSU Facebook group is at:
Hi Sherrie, thanks for writing.
Regarding “tips, encouiragement for someone who is starting at ground zero and has to teach”,
I suggest shifting your focus from “having to teach” to going on an exploration, learning adventure along with your kids. You need not be shy about saying that this is new to you too and perhaps they can help you (seriously) as well as you helping them. Keep in mind that teaching is not brain surgery. If/when you mess up you can alway go back and try it again. Bottom line: Have fun learning along with your kids. You will be a great role model in doing so.
Regarding, “my daughter will be in grade 8/9 next year.How long would you suggest we spend on this book, since we would still need to complete book 3.”
First, I think finishing both books II and III in one year is an impossible goal. And, it is a goal that is unnecessary to reach. Where will your daughter be attending grades 8/9? If public school, it is most unlikely that they will expect any significant science background for introductory science courses. If continuing to homeschool, just keep plodding ahead as you are doing. Learning cannot be rushed; it will take as long as it takes.
I hope this helps, but please write again.
Sorry not to get back to you until now. From what you describe, I think the problem is in the way you are using your microscope. Use the condenser to cut the light way down so that the background is only a light gray. Then carefully focus. Be sure you are focusing on the liquid under the coverglass. Get a rough focus with 40x, then go to 100x. Hopefully, this will give you something similar to what you see in videos.
I am very happy to see that you are (attempting) giving your kid(s) a first hand experience of this. Please let us know how it goes from here.
Sorry Shelley, I don’t have any specific recommendations for beyond Volume III. There is huge number of possible pathways. My hope is that after completing the three volumes of BFSU kids will have developed an interest in what area(s) they wish to pursue further and there is a plethora of texts in each. My advice, then, is to go to Amazon, search texts in areas of interest, read reviews, and make choices accordingly.
Thank you for your question. Please let us know what you find, decide, and your future progress. I am sure that many in the group would like to hear. Best, and stay safe.
Yes, quite so. It will be interesting to observe how, over the period of the equinox, the noon shadow (what there is of it) will shift from north to south, or vis versa.
In the whole process, don’t let kids loose track of basic phenomenon–the shift is due to the Earth maintaining the same degree and direction of tilt as it orbits the sun.
You are quite right. A traditional sundial will not work at the equator. During the summer months (spring equinox to fall equinox) the arc of the sun’s path will go to the north of you making shadows fall to the south and the opposite during the winter months. However, you can still make a modified sundial. Mount a pole vertically in the ground (or straw vertically on poster board). Each day its shadow will start as long to the west, gradually shorten to zero when the sun is directly overhead at solar noon, then gradually lengthen to the west. You can calibrate the length of shadow with cross lines for each hour. These hour lines should remain consistent throughout the year, although the sun will proceed to make a low arc south and north of directly overhead.
This will not permit the determination of north as described in the text. However, a line from the tip of the first morning shadow to the tip of the last evening shadow will be an almost perfect east-west line. A perpendicular line, of course, will be north and south. Thanks for the question. Please ask further.
Thank you for your questions. They show good thinking.
Why can’t we “un-burn” a piece of wood?
Reese is quite right in his thinking. The formula for any chemical reaction can be written backwards as well as forwards, making it theoretically possible. Specifically the chemical reaction for burning wood (mostly cellulose) is:
C6H12O6 + 6O2 —–> 6H2O + 6CO2 + release of energy
The reverse (unburning) is:
6H2O + 6CO2 + input of energy —-> C6H12O6 + 6O2 and is theoretically possible. In fact, plants do this with the aid of light energy. It is called photosynthesis.
However, distinguish theoretical possibility from practical feasibility. Plants accomplish the unburning of wood (photosynthesis) through a dozen or more individual chemical steps driven by energy from light. To have it happen on one big step as occurs in the burning is what is impossible.
Its a little like smashing a dinner plate on the floor. You can see the smashing apart occurs with one bang. You can see that the pieces might go back together to “unbreak” the plate. Then you might do so by carefully picking up each piece and fitting and glueing them back together. What remains impossible is having them go back together in one “bang.” Thus we say that the breaking of a plate (and unburning wood) are irreversible.
Is there conservation of mass as well as conservation of matter?
Yes! (But don’t confuse mass and weight.) Since each particle (atom) of matter has a certain mass and atoms remain the same, mass will also remain the same. Seeing this in practical way is what is difficult. Note from the above equation for burning wood, the major products are carbon dioxide and water (vapor) which go off in the air. (They retain their mass although weighing them is impractical.) A very small portion of the log ends up as ash. To prove that mass (in terms of weight) remains constant, you would have to burn the wood plus sufficient oxygen in a totally sealed container so that the water vapor and carbon dioxide are held in. (Scientists have done this.) It is found that the total mass and weight
does not change.
Please question more as you wish.