Bernard Nebel
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You have discovered and brought our attention to an error. Thanks “knitgrl”. On testing this further, you are quite right. I too find that the magnetic field extends through the can and attracts a paper clip on the other side. The attraction, I estimate, is only somewhat weaker than in the absence of the can’s “short-circuit”.
The science lesson is that what is observed will trump what it says in the text. Bernie Nebel
BTW, I think your horseshoe magnet is fine. I have never seen or heard of a magnet constructed as you describe.
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_______ (Region)______ (season) photosI just did it for New England, spring, summer, fall, and winter (separately) and got nice photos representative of each season. Of course, your will need to express what the temperatures are like as well. Good luck. Bernie Nebel
The second edition of BFSU Vou. II is out. Click on the cover image on the home page of this site. It will take you to Outskirts Press where you can get it. You can also find it on Amazon if you type in the exact title.
Thanks for asking. Bernie NebelThanks miranda. I would just like to add another way to think of heat, light, and electricity as being forms of “active” (kinetic) energy. Heat actively cooks the beans; electricity actively makes the TV work; light actively interacts with the cells of the eye and enables us to see; the moving ball smashes through the window. Kids will have fun thinking of other such examples that reinforce the idea that heat, light, electricity, and movement are active forms of energy, that is forms of energy that directly cause action.
Bernie Nebel
Thank you for your question, Mirandamiranda. Think of kinetic energy as the energy moving through space. Heat does not stay put; it is constantly moving from a warmer place toward a cooler place. Nor does light; light is photons (electromagnetic waves) traveling at the speed of light. As soon as you turn off the source, its light travels on and the room becomes dark. Electricity is electrons traveling, usually through a wire. You may have a charged object, static electricity (potential energy) but an electric current or discharge is electrons in motion traveling from one place to another. With classic movement energy, the ball, for example, is the same whether it is moving or not. Therefore, think of the energy as something different than the ball. The energy is being carried from one place to another by the ball’s moving.
I hope this helps, but please ask further.
Bernie Nebel
Thanks for your question, “Nemmer.”
The guiding principle of elementary science education is helping kids make rational (scientific) sense of what they experience, i.e., see, hear, feel, etc. It is not to have them memorize words or definitions for things that they cannot relate to their real-life experience. Please note that having kids make observations, and then helping them interpret and put those observations into a rational cause-effect context is a theme pervading all lessons of BFSU. Your question concerning my omission of plasma from this initial lesson concerning the states of matter provides a good example.
Kids can directly experience and relate to solids, liquids, and gases, but they have no way of directly experiencing plasmas. To be sure, you might point at a neon sign and say that the glow is produced by a plasma. However, what they experience is the light coming from the tubes, not plasma. Getting kids to memorize words for things that they cannot connect to their direct experience is found to confuse more than help. Therefore, I quite intentionally left plasmas out of this initial lesson.
Any understanding of plasmas draws on understanding the structure of atoms, their ionization, etc., concepts of chemistry that are beyond the early grades. I do get into the concepts of chemistry in Volume III, but so far, I have not related them back to plasmas. Perhaps in the 2nd edition …
You and others may disagree with what I have said here. I welcome further discussion.
Bernie Nebel
Heating glass in one spot causes expansion of that spot while the rest does not expand. This creates stresses that will shatter the glass. I suspect that is what happened.
Inorganic fertilizer, (any kind) in the amounts normally used poses no danger of fires or explosions. It is masses of many tons under unusual conditions and/or mixed with other things that may become hazardous.
The idea that plants feed on soil in a manner similar to animals feeding on food is a rather natural assumption and one that is not easily disproved. It takes modern science and sophisticated experimentation to do so.
The elementary level observations that have bearing are the facts that we don’t find trees growing in holes, and considering why plants have leaves. Then we need to make the distinction between an organism obtaining energy and its obtaining the necessary chemical elements (N, P, K, et al). Animals get both from food; plants get energy from light, but the get the N, P, K, et al from the soil. Thus, plants grow well on just water containing a solution of the nutrients–hydroponic agriculture.
Compost–I am glad to see that you do compost–provides two things: First, it provides an ideal environment for roots and this environment helps plants prosper. Second, as as compost breaks down it releases the same N, P, K, et al elements that other plants absorbed. Thus, it serves as an ideal slow-release fertilizer.
Some people claim that vegetables grown on compose-rich soil taste better. However, to my knowledge, it has yet to be proven that plant absorb any organic compounds from compost.
Bernie Nebel
In keeping with categorizing matter as solids, liquids, and gases, the whole Earth is commonly categorized as four “spheres:” the hydrosphere (all the waters on Earth); the atmosphere; and the lithosphere (all the solid “rock” portions). Then, the biosphere (all living things) is usually added in. Learning and understanding the innumerable ways in which these “spheres” move among and interact with one another (without the technical names of the “spheres”) are the real lessons.
Check out: mysteryscience.com
You will find some excellent videos that will be helpful for certain BFSU lessons.
Bernie Nebel
