Dot Physics

Three-axis accelerometer tracings of a parachute BASE jump: http://www.sparkfun.com/commerce/news.php?id=194

That looks very cool. Any idea how I can get the actual data from the 3-d accelerometer? Impressive.

This was just something I came across on the Internet. I didn’t have anything to do with creating it.

Maybe the people at SparkFun can put you in contact with Michael Cooper.

Their e-mail address is here: http://www.sparkfun.com/commerce/static.php?name=about_us

And their phone number is here: http://www.sparkfun.com/commerce/static.php?name=contact_us

Here’s one you might like, meteor from a moving police car: http://www.sciam.com/blog/60-second-science/post.cfm?id=meteor-streaking-across-canadian-sk-2008-11-24

Hi there

Thought you may be interested in using this on your blog.

http://uk.youtube.com/watch?v=o5dNg6pmgPg

During Anton Zeilinger’s visit to the IOP we took the opportunity to talk to him about his life, his interests and motivations, and his views on the future of quantum theory and quantum information. This interview is accessible to anyone who is curious about physics, and what it means to be a physicist.

Kind regards

Simon McDermott

Beat mythbusters with your analysis of “directly downwind faster than the wind”, http://www.boingboing.net/2008/12/03/directly-downwind-fa.html and how autorotation in helicopters is working.

Hey, I don’t remember how I found your blog, but I did and I enjoy reading your analysis of every day situations using physics. I found something that i think would make an interesting post. http://blog.modernmechanix.com/2008/12/15/will-these-vehicles-run I hope to see what you think of this.

Keep the interesting posts coming.

Rhett, I want to send you an email to work out the animation to debunk the faster than the wind BS. I can hand you the proof on a silver platter but I need to work with you via email until it is ready to be put on the web. Need your email!

Hi Rhett, I think you should follow up on the downwind faster than the wind thing. You seemed to be coming around, but then never said anything one way or the other.

Here is a page that should make it crystal clear that it is possible:

http://karmatics.com/dwfttw

Hey Rhett, Stumbled across your blog and thought you might interested in talking to Eugenie Reich, who wrote Plastic Fantastic, about Jan Hendrick Schon, the fraudster Physicist. She has a lot of great info that would appeal to your readers. Best, Dylan

After reading your posts on science fairs, I thought you might be interested in this post: http://lanseybrothers.blogspot.com/2007/06/sad-state-of-science-education.html

Anon,

Thanks for that link. Good stuff.

A student today asked me a good question and I can’t find the answer: I know that the force of gravity is transmitted by warps and bends in space-time. What is it that transmits the electromagnetic force?

Wow – very cool blog, Rhett! I will have to keep this in mind next time Miles (he’s 9) asks me a tough question in this area.

I am in search of a serious scientist or grad student with good math skills to collaborate with me on the recent observations of the acceleration of the universes expansion, the nature of quantum mechanics and energy fields, and their relation to observations in astronomy. I am a retired physicist having worked 33 years at IBM and am now exploring some of my own ideas on quantum mechanics. However, I need someone with advanced math skills and only serious interested people in this area with open minds. Any suggestions for finding someone would be appreciated.

I’d like to see an analysis of a ripstick. How does the rider generate forward momentum?

Hi! I’m a physicist working on the promotion of candidacy of Bilbao (Spain) for host the future european spallation (neutron) source (ESS) and surfing the web, I found your site. First thing: really I like it. During the last time, I use to enjoy reading (and learning, in the most of the cases)science blogs, and that happened with this one, so congratulations. I will come back soon and frecuently

Second thing: well, because my job is to promote ESS and not only enjoy reading, I’m wondering if you would like to write about the neutron spallation source (like Oak Ridge, or ILL) and also about the european project (http://en.wikipedia.org/wiki/European_Spallation_Source). Technichal information are avaible at http://www.workshop2009.essbilbao.com/cas/index.aspx if you want to read more. Finally I want to invite you to the Bilbao’s project website (www.essbilbao.com) or the Non Official Blog (esns.blogspot.com).

I hope you find interesting that information, and also I hope you continue with this web. Sincerely Víctor Hevia Martín

How can you illustrate centripetal force with a RIPSTIK? Does it even use centripetal force?

can you tell me what happens to the flow of liquid when there is a change in gravity as one experience during an eclipse

The RipStik or Wave Board (castor board) is fascinating. The generation of kinetic energy and linear motion is not possible on a flat surface using a skateboard. The official RipStik web site hints at a possible mechanism for generating the energy: the angle of the inclined castors allows the board to rise and fall slightly as the board oscillates horizontally. This suggests gravitation potential energy is the source of the kinetic energy. Of course, one can shift one’s center of mass on a skateboard, but not generate anything more than back-and-forth motion. The angled castors must, somewhat like an ice skaters blade, apply an unbalanced force to the ground that results in the forward motion of the board and rider. One “physics blog” suggests that angular momentum is involved, but the momentum is oscillatory at best and only significantly present in the rider. The suggestion that this rotation is then present as “rotation” of the board and leads to motion is hard for me to envision. There is clearly an opportunity for a nice exploratory mechanics laboratory in these castor boards.

Rhett,

I’ve had a particularly odd theory burning thru my brain for a while “If I were blind, how would i prove the existance of faster than sound “travel/elements.”

I wanted someone with way superiour math/Physics skills than I to help me work thru. It’s a theory i’ve been trying to solve personally (i have not a publishing bone, and I can’t do higher math in any form, nor am I an academic; just a thinker with too much time on his hands. )

Would love to hear from you if interested. The explanation is of course, longer.

I want a thorough understanding of the differences between a scalar quantities, vector quantities, vector components, scalar components, and magnitudes of each of these quantities/components.

Particularly, I want to know how each concept applies to the constant acceleration formulas, and which parts of the vector specify direction (i, j, k and the sign, or just i, j, k). Is a scalar component the magnitude of the A_x component, or does it also include the sign?

I would appreciate if you could email me an answer or one of your posts that addresses these issues. Thank you.

Rhett, I discovered your exellent web site off of “The Blog of Phyz” I think a few weeks ago and I really enjoy your posts and use of video analysis. After seeing your slides like this one, I am curious if you are willing to share them with other physics teachers.

It appears to me that you are a Keynote user and I would appreciate using your files and perhaps modifying them for my class and focus on student learning and reduce my prep time if at all possible.

I understand if the answer is no, but looking around your site I get the feeling that you are about sharing your expertise.

Take care and have a great day.

Rhett :Chris, I had to google what a ripstick is – but looks interesting. I will put it on my “to do” list.

I look forward to it. Perhaps you can prove it’s not possible to motivate the ripstick through the rider’s body motions. That will be as entertaining as your proof that the downwind-faster-than-the-wind vehicle doesn’t work (despite videos showing it does).

@Rhett: What program do you use to do all of those neat physics drawings in your blog?

Thinking about Applying to NW? ,

Hi Rhett I am a squash player and have been thinking about the difficulty the average player has with a high backhand volley.It is probably a combination of factors , but I perceive lack of power , actually coordinated power as a big factor Now my question , perhaps dumb, how much work does it take to hit a ball coming at 150 km/hr towards the raquet from the front wall and return it at as speed of 200km/hr to the front wall.The mass of the ball is about 20 grams The next question is: if you mishit a ball , is the loss of balance due to the anticipated (non)impact of the club or raquet with the ball mainly or due to the mental”lapse” regards

Thanks Rhett I should have added that my knowledge of physics is long forgotten! Am in the medical field but do squash coaching as well .I will calculate the work done but I suppose it is only a part of the technical solution, the fulcrum effect(is it the right term for the increase in the velocity due to the swing of the head of the squash raquet?) and the innate ability of the player to generate pace (fast twitch muscle fibres , lenght of arm) will also come into play. From an coaching aspect , what is important for me is how much of the problems on the high back-hand volley is power-related and how much is technique related. The easiest obviously is to simulate the action in the gym As for the second question I suppose once you have the work done , you can phrase it in more practical terms eg the lifting of lets say a 2kg weight a x distance And then assess whether the loss in balance is due to the body anticipating the impact on the ball and then you lose balance because of the non-event The interesting thing for me is that a lot of the power in raquet or club sports is generated if I understand it correctly , via the transfer of momentum via the back muscles , thighs through the raquet to the ball. these are laymans terms , pardon the lack of physical knowledge! To put it another way , if you just swing your arm and keep your body in a neutral upright position you cannot hit the ball hard at all .You can compensate up to a certain point with raquet speed, but beyond that you need strenghth

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What physics lessons can we learn from the crane that fell into a house: http://attuworld.com/just-attu/reliable.html

Besides add additional counter weight or lifting a lighter load, what could have prevented this? Maybe extending the boom less?

How could they have known how much the tree part they were lifting weighed before separating it?