Category: Nature

Ferrofluid

November 18, 2014

One way to imagine magnetic fields is by drawing lines showing the direction a compass would point if placed into the field. Here’s an example:

The black lines depict the magnetic field directions. This can be hard for students to understand at first, so another technique is to show the field lines by placing iron filings near a magnet and watching them align themselves in the direction of the field, like this:

The black bar is the magnetic. These sorts of demonstrations can be artistic:

And given enough filings can even show the field in 3D:

But the best illustrator of the field, in my opinion, is to show the effect of the field on a liquid. ‘Ferrofluid’ is the name of a magnetic liquid invented in 1963 that suspends micron-sized iron nanoparticles in a viscous fluid. This allows them to flow as if they are a liquid, and leads to striking displays of magnetic fields like this:

The magnet in the above picture is underneath the bowl containing the ferrofluid.

I’ve been using images like all of the above in class for years when I introduce the magnetic field and when I found out last week how easy it was to actually purchase ferrofluid (which is toxic and can apparently stain anything) I just jumped at the chance. Here’s what my new bottle of ferrofluid looks like:

Just some black oil in a bottle isn’t it? The bottle is filled, most likely with pure water. The fluid is likely oil filled with the iron nanoparticles, and is extremely viscous and doesn’t mix with the water. It’s quite unremarkable by itself, but becomes something quite special when exposed to a magnetic field.

Here’s a short video I just made (it’s in HD, so fullscreen it if you like):

Wonderful isn’t it? This will stay in my office with all my other demonstration units, and I’m sure it will give students and my coworkers many smiles!

The Great Australian Road Trip

July 15, 2014

One day I’m going to drive around Australia. And I don’t just mean here and there, I mean drive all around Australia. As in this:

It’s a trip of almost 20,000 km, or over 200 straight hours of driving at 60 mph. That’s 40 days of driving 5 hours a day, which means this would be lengthy and expensive. But what a trip it would be!

I’d do the reverse route from the map above, starting in Sydney and heading north through Newcastle, Brisbane and all the way up to Cairns. That’s a few days right there, with many stops and things to see on the way. The beaches and coastal roads, especially as you get more and more north, would be beautiful.

And then a several-day trip to Darwin through the outback. Hundreds and hundreds of dry empty miles with not even a radio station on the radio. That would be quite an adventure!

The Darwin to Perth leg may take a week. It’s some of the least inhabited parts of Australia, but there are just enough small towns to make a daily stop possible. Accommodation on this leg may include a tent, or sleeping in the car! I may stay in a comfy hotel in Perth for a day or two to reset 🙂

Half the trip would now be complete and I’d be on the opposite side of the country. But the southern coasts are still to come, and some say these are the most beautiful roads in all of Australia.

It may take a week to get to Adelaide from Perth, stopping everywhere that looks interesting. Between the desert and the southern ocean there would certainly be a lot to see!

And then the windy roads along the Victorian coast would take me to the extreme southeast, at which I’d have to make a decision: Tasmania or no Tasmania? After 5 weeks on the road, who’s to say what I’d decide at that point?

Eventually the landscape would become vaguely familiar, as I drove into NSW and found myself within a few hours of Sydney. Six weeks after starting, I’d reach my destination: exactly where I started.

I’d have seen the entire country, and made enough memories to last me forever.

I’ll do this one day. I have to. Who wants to come with me?

River Monsters

May 14, 2014

In a little under a month, KLS, Jim and myself will be crusing along the Erie canal in a rented houseboat!

The Erie canal is a man-made waterway that connects Buffalo in the extreme northwest of New York state, to New York City. It was opened almost 200 years ago and for a long while was the most important transportation thoroughfare in the state (and was instrumental in making NY the most powerful state in the country). Obviously roads, trains and air transport have mostly obsoleted the canal for commercial use, but it remains popular for recreational boaters.

Much like the British canalboats, people worked and lived on the canal in a particular type of narrow boat. Today a company near Rochester manufactures their own houseboats in the vintage style, and rents them out for 4 or 7 day cruises. I’ve known that such rentals exist for a long time, and this year finally decided it was time to try one for ourselves!

We’ll leave from very close to J&J’s house in Rochester, and cruise at a maximum speed of 6 miles a day. The rental company sent me a wonderful packet of information so we can plan the trip, and as of right now we’re probably going to head east on the canal through a more rural area, including a nature reserve. We’ll leisurely cruise for two days and then turn around and come back! The boats themselves are quite luxurious! We rented the largest they have (42 foot) that has two ‘state rooms’ (both with queen beds), a dining area, fully-equipped kitchen and a shower with hot water! The boats also include a grill for cooking on the deck, and some bicycles in case we want to moor up and explore. All we need to bring is some food and games 🙂

Here is a newspaper article about a canal cruise rental. Needless to say, you can expect to read all about our own adventures on this very blog 🙂

Robot Claw