# Recent content by bkelly

1. ### I Distortion of Space Time

Ibix wrote: You really can't do that. That is similar to saying that I cannot make a drawing in only two dimensions. The claim is not to pretend the other dimensions do not exist, rather to provide limits to the scope of thought. A narrower scope often leads to better thinking. Ibix wrote...
2. ### I Distortion of Space Time

Presume we look at a two-dimensional view of space time, with no local masses, and we draw a grid of equidistance spaced lines. The intent is to look at space but not time. As we begin, we look in all directions and the grid lines are evenly spaced. Begin adding mass to the center of the grid...
3. ### I Solar panel angle to the Sun

Tom G, Thanks for the reply. You prompted me to really dig into that formula. I have a workbook that calculates the sun’s noontime elevation for the entire year. Phyzguy, Thanks for your reply. I don’t have Python. I presume your code works, but cramming everything into so few lines with no...
4. ### I Solar panel angle to the Sun

I don't know how to work with vectors that are three dimensional, meaning two angles and a length. I am not interested in the length. The length of the vector to the sun is 93 million miles and the length of the vector representing the panel is infinite. I already did the google search and...
5. ### I Solar panel angle to the Sun

Moved into a house with some solar panels facing due south and some facing due west. Our latitude is 33.8 North in California. We are in the Mojave desert with very little cloud cover. The angle of the roof is 22 degrees from horizontal. What is the equation that will accept the azimuth and...
6. ### Explaining equation to stem class

reply to atyy: No, not comfortable with it. That site does not explain well. It asks question then does not answer. On the second page the author posts the equation d = vt = vf t / 2 Except that the first v has a bar over it. Ok, what is that v-bar. I don't see the explanation. I have been...
7. ### Explaining equation to stem class

I kind of follow along, but have a difficult time. I will look at this some more. In the mean time, my best option is to say that people who understand this have figured it out and we are using the fruits of their labor. If you, the children, want to pursue this I will help, but I will also...
8. ### Explaining equation to stem class

Context! I should have included that in the OP. They do know what square root is, and at least fundamentals of exponents. I am unsure about units, but I do explain that very carefully in the first few sessions on bottle rockets. We spent several of our weeks taking apart gas engines and...
9. ### Explaining equation to stem class

I am a volunteer teaching a STEM class once a week to a class of eight elementary students. From this page http://tbpmindset.org/modules/SECME/Rockets/Rockets_Calculations_Manual.pdf I use this equation for water flow out of a water rocket m = nozzle_area * discharge_coeficient * SQRT( 2 *...
10. ### Water rocket and water velocity

I am going rather slow, spending too much time on Quora. But yes, and I will add in a phrase to consider temperature drop and the resultant further pressure drop. I am doing this because I am a volunteer at an elementary school STEM class, one hour a week. We launched a water rocket a few...
11. ### Powering electromagnets with bicycle power

This sounds like trying to help a child learn to ride a bike. Give them a two wheeled scooter to ride for a while. They can step off of it to either side easier than with a bicycle. It will help them learn the concept of steering the scooter/bicycle beneath them to maintain balance. After...
12. ### How do we see the color violet?

Think about what you "see." The eye connects thousands of rods and cones to the brain and the brain translates those many thousands signals into what we "see." We do not directly "see" the objects we look at, we "see" the image that our brain creates. When the brain receives signals from the...
13. ### Water rocket and water velocity

The document referenced in my previous post provided a formula for mass flow per seconds. After working it for a while the result was 6.98 kg per seconds. With a water load of 0.5 kg, the water rocket is out of water at about the 0.07 second mark. That agrees with our rather imprecise...
14. ### Water rocket and water velocity

Well then. I will shift my reference. I will start here: http://tbpmindset.org/modules/SECME/Rockets/Rockets_Calculations_Manual.pdf and search for a few more. If you have a known good reference, please post. My goal is to enter instantaneous formulas into an Excel spread sheet and iterate...
15. ### Water rocket and water velocity

Point taken. The document is here: http://www.schulphysik.de/strutz/predictors.pdf On the second page, right side, is the equation for flow rate. Is that a valid equation? Do you recommend something different? I am still working the equation and the units are not working out. I will...