By Science Mom
My five-year old son, Alexander, has already developed a strong interest in math and science. At his request, we recently enrolled him in an after-school astronomy class, where he draws stars and shoots the galaxy breeze with the other pupils. He has settled on Saturn as his favorite and most interesting planet; he loves the rings.
As part of a plan to nurture Alex’ interest in science, I decided that each week, he and I should try some form of scientific experiment. With that in mind, Talking Science ...

As it turns out, Spring break is great for science experiments. There's plenty of time and plenty of scope, especially if the weather is lousy and you have a curious five-year-old.
So, Alex decided that he wanted to do three experiments while he was on break. We found them – as we have found most of the things we have done – in Pop Bottle Science, which features 79 easy experiments that are not too time-consuming or messy. And in addition to a book full of experiments, the Pop bottle breaks ...

By Hugh Lippincott
I want to try and explain some of the math behind the double-slit experiment. The goal here is not to explain the weird nature of light mathematically, which is beyond the scope of a blog. I do want to show how the double-slit experiment proves light behaves as a wave quantitatively and give an example of how math can be used to explain the results of an experiment.
After a brief discussion with my mom, I realize that I will have to start by explaining what the sine function ...

By Hugh Lippincott
I will use the Bohr model (together with the nature of light discussed in the last few posts) to predict the existence of "spectral lines," which will finally bring me back to dark matter by explaining exactly how we measure the speed of those rotating galaxies (see the Dark Matter Intro link if this is not familiar). Historically speaking, I'm presenting this material backwards, as the observation of spectral lines came first and the explanation came later, but I will proceed anyway.
Niels Bohr is in many ways the ...

My five-year old son Alexander and I have tried to get into the habit of doing one science experiment each weekend. But last weekend, faced with plenty of time on our hands and a couple of Spring days that were sunny but really cold, we decided to stay inside and do four experiments. Like science itself, they took a bunch of different forms.
The first experiment came from the book One Minute Mysteries: 65 Short Mysteries You Solve With Science. I read a riddle to Alex that essentially asked if you ...

By Hugh Lippincott
In a comment on the quantitative Doppler effect post, my mother had the following to say:
"Mom again. I have a feeling that however clearly you explain it, some people who have never taken advanced math in any form will never really understand it. I like much better the idea of the dark matter, the neutrinos racing through my finger-tips, etc. Perhaps you should select your subject-matter differently - when you say you are a physicist, what questions do people at cocktail parties ask you? I'm sure not about ...

By Hugh Lippincott
The first version of the qualitative post contained a paragraph at the end in which I did some real math (I have since removed that paragraph, as it appears in a different form in this post). My mother loved the bit about the tennis and thought she had really grasped the general idea; alas, when confronted with a paragraph containing algebraic variables, she felt somewhat bewildered and lost because I hadn't given it enough of an introduction. I was reminded that she hasn't really done any advanced math ...

By Hugh Lippincott
In my first post, I talked about how the Doppler effect is a shift in the observed frequency of a wave caused by the relative motion of a source and an observer. In this, my first detailed post, I will try to explain how that actually works. As my mom plays tennis, and this blog is ostensibly aimed at her, I'm going to use a rather tortured tennis analogy.
Suppose my mother is using a ball machine to practice her ground strokes. The ball machine spits out a tennis ...

By Hugh Lippincott
In the last post, I said that dark matter could be a new type of particle that only interacts weakly, which is why we've never seen it before. The goal of my research is to build a very sensitive radiation detector and directly detect a WIMP (by observing the energy released on that rare occasion when a WIMP does interact with something in the detector). This is hard. Given our current limits on dark matter, we expect to see maybe a handful of events per year in our ...

By Hugh Lippincott
In the first post of this blog, I briefly discussed how galaxy rotation curves provide evidence for the existence of dark matter - I didn't really said anything about what dark matter actually is. We've only said that it exists, that it has mass (i.e. it interacts with gravity), and that it doesn't interact with light like every day matter. The truth is, even though dark matter is 85% of the total matter in the universe, we don't know what it is because we've never seen it directly. ...