Making A Stirling Engine

June 19th, 2008

Is not to be taken lightly. I tried to make one from scratch, and it still doesn’t work. I did find a fairly inexpensive (relatively to all the other kits out there on the interwebs, that is), easy kit on ThinkGeek’s website, however. You can see the results on PopSiren. I will continue the quest to create a tin can engine. I will. And, one day I will see a cd spin from the power of ice and flame, and it will be a good day.

The Reason Why

April 28th, 2008

I simply have to put this comment from Trish up front and center.

My 9 year old daughter (who always showed an interest in science) has spent this year struggling with the “tween syndrome” of her friends thinking her interests are “uncool”. After showing her your podcasts, she has discovered that it is not only possible but very rad to be both smart and interested in science but to like fashion and lip gloss at the same time. She even did her science fair project on water based on a recent pop siren episode! (I plan on emailing the pop siren’s a picture!)
So, THANK YOU THANK YOU THANK YOU! If I could send you flowers I would. You are not only a rock star to my kid, you helped bring her back from Hannah Montana hell! :)

Thank you, Trish, for sharing. I hope you don’t mind that I brought your comment to the front. This is why I want to keep doing what I do. Girls need to know that it is ok to be smart and a girl. Somewhere along the way it seems that the idea was spread that if you are a girl and interested in science, you shouldn’t act like a girl, shouldn’t play with make-up and clothes, put away your curling iron, and just do science. While some girls might find that a relief, many more really enjoy the girlie things in life. Either one should be ok, as long as you’re doing what you enjoy.

I was recently chided for being too sexy (a comment that I found hilarious). The commenting party suggested that because I use a nice looking profile picture I am being disingenuous. It’s sad that some people see it that way. Should I instead find a picture in which I purposefully look comely, “nerdy”, or unapproachable? Should I do away with the profile picture in preference of an ungendered symbol?

I think either tack would do a disservice to females everywhere. A “nerdy” picture or a neutral symbol would promote stereotypes, and undermine the work that I’m trying to do to show girls and women that they can be anything they want, make-up or no. I doubt I would have made much of an impression on Trish’s daughter that way.

Besides, I like playing with my hair and make-up, and feeling fancy from time-to-time. I’m fancy on the inside, and my exterior should reflect that. When I know I look good, I feel good about myself, inside and out, and there’s nothing wrong with that.

Trish, I can’t wait to see the science project picture. I know all of us at PopSiren will be thrilled. Tell your daughter that she’s totally rad.

The Vestibular System

March 13th, 2008

This week on PopSiren I went a completely different direction from the first episode. Yea, sorry. No fire this time around, but we did play with a way for you to make your friends dizzy. Yes, I talked about the inner ear. And, I spun Neha around and around and around and…

The vestibular system is not just your inner ear, but consists of all the proprioceptive organs in the body. Proprioception helps your brain figure out where your body is in space. Normally, all the different organs work together very nicely, but sometimes one or more are disabled. This leads to trouble in spatial perception and balance.

In the show, I demonstrated how simply closing the eyes can remove one of the important markers of body position in space. Think I’m kidding? Just try spinning around with your eyes closed and see where you end up.

There is fluid in the canals of the inner ears called endolymph. When the head is still, so is the endolymph. When the head moves, inertia causes the endolymph to move in the opposite direction. So, if you are turning to the left, your endolymph is moving to the right, and vice versa, up, down, and round and round. In the segment on PopSiren I asked Neha to close her eyes. Then I spun her right round to her left. You can totally see that her eyes are moving to the right when I stop her and have her open her eyes.

The second demonstration didn’t work as well as I would have liked, but it did work. By having Neha put her head down while she’s spun around, I was isolating the posterior canals in her inner ear. If you look really carefully at her eyes when she comes to a stop, you can see them moving diagonally up and to the right for a moment. All triggered by the semi-circular canals. What do you think would have happened to her eyes had I asked her to put her head on her shoulder?

If I had the time, I would have also shown that Neha’s perception of direction would have been the opposite of her actual direction of movement. You can do this yourselves (those of you who are adventurous enough to give this trick a shot). Make sure you keep absolutely quiet during the spin, and  try to not jar the chair as you spin it. Then have the victim… ahem, volunteer indicate which direction they think they are moving with their thumb (to the right for right, to the left, for left, and straight up for no movement). Because the volunteer’s eyes are closed their sense of movement will come only from their inner ear, which as a result of physics is backwards. You can also play around with stopping the volunteer suddenly versus letting them spin slowly to a stop. See for yourself and let me know what you find.

I mentioned the otolith organs, the saccule and utricle, but never really explained them. While the semi-circular canals detect rotational movement, the otolith organs detect movement in linear planes (i.e. front to back, side to side, up and down). The endolymph of the otolith organs is interesting because it contains little particles called otoconia, which enhance the signal to the brain by making the endolymph in that part of the ear denser. Thus, causing greater shearing force to take place between the layer of endolymph and the layer with all the hair cells adjacent to it.

Now for how all this applies to you. If you are prone to motion sickness, you probably know all sorts of tricks to combat the sick feeling like sitting in the front of the car, being able to see the horizon, or pushing on a pressure point on your wrist. The reason that the tricks work is that you are using the other organs in your vestibular system (namely, the eyes and skin) to help override a mismatch between your inner ears and your actual state of motion.

I hope that everyone learned something new this week. I had a lot of fun with the show (nevermind that I actually got to co-host!!!) and the segment. Next week, I think I’m playing with magnets and explaining the basics about how they work.