Telescopes

We got a telescope through a charter school program last year, but we still had it in the box, so during this unit after we talked about lenses seemed like the perfect time to finally get it out and put it together. It's this telescope, and we haven't used it much for stars yet, but we did have fun learning how it worked and experimenting with looking at signs and trees and things.

Poor Daisy got tired of waiting for her turn. Seems like she always has to wait for the older children!

(Our cousin Michael was visiting, too)

The innovations that have been made in telescopes and lenses in the last several years are just amazing. We read lots of books about some of the new space telescopes, and we always love looking at pictures from the Hubble Space Telescope!

We learned about liquid mirror telescopes made of mercury, which I had never heard of. Apparently these liquid mirrors are a lot cheaper to make than the huge, flawless mirrors they need to grind for other telescopes (and which can take years to get smooth enough). But the liquid mirrors have a few problems too (e.g. they can't be tilted).

This video of a spinning parabolic mercury mirror demonstrates how it works on a small scale.

Lenses

Resources for learning about lenses:

How lenses for glasses are made

Fascinating page on the Fresnel Lens (used in lighthouses) and we also loved this video showing how they work. Such an ingenious concept!

Here are some lenses we used for experimentation.

While discussing lenses, we used both our microscope (we have this one, which we got a couple years ago and have really loved) and our telescope (this one, which is quite new and we have hardly used it, so I can't say if it's a good one or not. The reviews say it's good for beginners, which we definitely are).

This is a great discussion of why things in a microscope get darker as the magnification increases (and why there is a limit to what we can see with optical microscopes!)

This page tells how lenses are used to make searchlights and car headlights brighter.

We liked these diagrams showing how different lenses can work together in a lens array. Since Sebastian is currently obsessed with digital cameras and how they work, this was particularly interesting to him, as was this page on SLR cameras. There's a cool interactive feature on that page where you can change ISO, aperture, shutter speed, etc. and see how those changes affect the photograph.

Planetarium Shows

We visited both our nearby planetariums (planetaria?) during this unit. My brother Kenneth used to give the planetarium shows at BYU and they were always SO excellent. I could listen to Kenneth talk about the stars forever! I'm sorry to say that the current crop of BYU students hardly lives up to his legacy (the girls were reading their parts from a script the night we went, and not reading very well, either), but it's a fun field trip nonetheless. We'll have to go back again when they're doing a different show (the one we saw was showing us constellations in other cultures, which was somewhat interesting but not very useful for those of us still trying to learn landmarks in OUR night sky!).

A visit to the Eyring Science Center is never a waste of time, though. We always enjoy seeing the pendulum, the wave machine, and the other fun exhibits.

This exhibit showed the density of various materials, culminating with a neutron star. It was so heavy we couldn't even lift it!

Another day, we went to the Clark Planetarium in Salt Lake. They have some really fun free exhibits, though the shows are quite expensive. This time, we went specifically to see an IMAX movie Sam's parents recommended to us, called Hubble 3-D. The astronauts who fixed the Hubble Space Telescope brought an IMAX camera with them, and filmed some really amazing footage. I thought even the parts that showed the astronauts suiting up, getting ready for launch, etc., were really fascinating (because it's 3-D, you feel like you are in the room with them!), but the shots from the astronauts' point of view, looking down at the earth as they floated next to the Hubble and worked on it, are mind-blowing. SO cool. There are a lot of great shots taken by the Hubble itself, also. We really loved the movie and felt like it was worth the (rather pricy) ticket.