Forum Replies Created
March 31, 2023 at 12:53 pm in reply to: What state of matter is peanut butter? #9334
Your son has recognized a difficulty with defining everything as solid, liquid, or gas. Congratulations. Yes, there is a broad spectrum of “consistencies” between the most liquid and solid. It is a property known as viscosity. It is measured as the amount of time it takes the material to flow through a given opening, or the pressure needed to force it through.
There is a whole field of specialized science/product manufacturing dealing with how to give things the desired viscosity for a given use. Think of tooth past, skin lotion, engine oil, paint. An added complication is that viscosity of most things changes gradually or markedly with temperature. I left this out of the text to avoid the extra complication at the beginning level, but I am happy to see that your son recognized it.February 28, 2023 at 10:51 am in reply to: High Voltage/Current #9314
Thank you for your question, Emily. It is both voltage and the current (amps) that are significant. Think of volts as pressure. First, there must be enough pressure (voltage) to push current through the body. Second, there must be enough current (amps) to do damage. “Danger, High Voltage” signs are to say that there is enough voltage to potentially cause current to leap from the power cables to your body and then then to ground. That there is enough current (amps) in the system to cause damage is taken as a given. I hope this helps, but please ask further.January 5, 2023 at 9:39 am in reply to: Physics of swimming: momentum #9177
You raise an interesting question. I swim but I am not a swimmer. I really hope that someone with more knowledge in this area will chime in.
Looking at the problem from an overall physics perspective, however, I question how much of role momentum (the tendency of a moving body to keep moving) actually plays. The greatest resistance to a swimmers forward movement is drag of the water — “friction.” This friction will tend to dominate the outcome, momentum notwithstanding.
Therefore, it seems to me, the focus should be on movements/motions that minimize this friction. That, and on movements/motions that maximize pushing forward. Again, I hope that someone with more knowledge will chime inAugust 10, 2022 at 4:10 pm in reply to: Starting with an 8th grader #8974
It depends on his background thus far. BFSU is designed to build understanding in logical systematic steps each building on what has gone before. If he has not had steps one and two, you cannot expect him to make much sense of step 3, even with help. I recommend starting with volume 1 then 2 and doing a review using the “Practices” section of each lesson. Only spend time on filling in ideas/concepts that he has missed or have fallen away. After this, you can be assured that he has the background or Volume 3.February 2, 2021 at 1:09 pm in reply to: Photomicrographs for Vol 2, B-14 #8592
Thank you for your question, Amy. Sorry to be so long in getting to it.
To start, please don’t make this more complex that it is. The key point of the lesson is to have kids observe that whatever biological tissue we look at, we find that it is comprised small units we call cells. Cells are too small to be seen with the naked eye. The images they are going to examine are made with aid a microscope.
Start with plant tissues where cells are most conspicuous. Google in turn:
Plant leaf cellular anatomy images
Plant root cellular anatomy images
Plant stem cellular anatomy images
Ignore all technical terminology; species makes no difference at all. With each sort of image, draw your kids to focus on the individual units, cells. Have them follow/trace the outlines of cells and model how they are actually three-dimensional structures. They may be shaped like boxes, sausages, pancakes, or otherwise, but whatever their shape(s), they go together to make the particular part of the whole.
You may go on to observe the cellular structure of animal tissues in the same manner. Google in turn:
Skin cellular anatomy images
Muscle cellular anatomy images
________ (insert tissue/organ as your kids desire) cellular anatomy images
You might insert the discovery that all biological tissues are comprised of cells is one of the most profound breakthroughs in the history of biology. That discovery had to wait for the invention of the microscope.
The second part of the lesson.
After the discovery that every biological tissue examined is comprised of cells, the next question was: Where do those cells come from. Untold research and observation has revealed that only origin of a cell is from a pre-existing cell via a process of cell division. The key point is this. All growth and reproduction of biological organisms hinges on the division of one or more pre-existing cells. Following their formation via division, a cell may go on to grow and take on the size, shape, and function of the tissue in which it resides. Have kids observe a time laps video of cell division. You can ignore all technical terminology. The key point at this stage is that the origin of every cell in an organism is from another pre-existing cell.
You and you kids undoubtedly have further questions. Please do not hesitate to post them. I will try to respond in a more timely manner.December 17, 2020 at 9:22 am in reply to: Starting in Winter #8451
Hi mastros, Sorry to be so long in answering your post. I think winter is a perfectly good time to start BFSU, and your beginning lessons will be the same. A/B-1, A-2, B-2, D-1, C-1, B-3, although the order may differ. As you get into spring you will probably want to continue heavier on the B-lessons as they fit into what kids are observing in the real world, but don’t totally neglect lessons in other areas. Please post your question on our Facebook site: https://www.facebook.com/groups/308651699340117 I am sure you will get more detailed responses from folks who have been through it. Thanks for asking.December 1, 2020 at 12:41 pm in reply to: Minerals and Crystals #8445
Thank you for your question, and revealing an error in the text, “SciBeams”. A crystal is a problematic conception. To clarify, start with visualizing atoms/molecules going from liquid to solid state. This occurs as molten materials cool or as a material in water solution comes out of solution as the water evaporates. As solidification occurs, atoms/molecules may go together in two ways. Visualize the atoms/molecules in terms of cubic building blocks. In the liquid state the blocks are in all different orientations with respect to one another, slipping and sliding about. This “random” orientation of the blocks may be maintained as solidification occurs. When this happens, the result is a non-crystalline solid. Alternatively, as solidification occurs the blocks may orient flat sides to flat sides and spaced such that each is exactly on top or beside its neighbor(s). When this occurs, the mass of cubic building blocks will form into larger cubic structures. This is the process of crystallization and the result is a crystal. Visualize how the shape of the crystal will vary with “shape” of the atoms/molecules that are involved.
Crystals are recognized by their smooth, shinny sides and sides that have specific angles with respect to one another. Crystals are most commonly minerals (inorganic), but as you have pointed out, organic compounds may form crystals as well. Sugar is an example of an organic crystal that I overlooked. The key idea to learn from all this is that many atoms/molecules, as they go into a solid state, have the tendency to orient and pack themselves together in specific ways such that masses have distinctive shapes that we recognize as crystals of given compounds. I hope this helps, but please ask further. I invite others to contribute further comments or questions.October 24, 2020 at 2:05 pm in reply to: Question about car engines #8431
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.October 12, 2020 at 2:16 pm in reply to: Help With download #8419
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.September 11, 2020 at 12:31 pm in reply to: Calories vs Degrees/Temperature #8402
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 NebelSeptember 3, 2020 at 8:44 pm in reply to: 5th grader starting volume 1? #8395
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.August 2, 2020 at 12:32 pm in reply to: Materials for Lessons A-1 to A-9 #8389
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.July 11, 2020 at 10:45 am in reply to: Declaration vs Declination #8359
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: