Wednesday Explorers Club ~ Solar Eclipse Science!

photo from NASA - eclipse seen in space

The Solar Eclipse is coming - Monday, August 21 - and if you live anywhere in North America you'll see at least a partial eclipse. A solar eclipse is when the moon passes between the earth and the sun, blocking out part (or in a swath of lucky locations, all) of the sun's light.

We all know - or at least we should know - that looking directly at the sun can damage our eyes. This holds true for solar eclipses, too. So even though the moon will block the sun's light, you can't watch the eclipse by looking at the sun -

 UNLESS you have special eclipse-viewing glasses.

Eclipse viewing glasses have special filters that protect your eyes. Regular sunglasses are NOT adequate. If you don't have a pair of special eclipse viewing glasses, check your local library. Many libraries are providing glasses and holding fun eclipse viewing parties. Find out more about eclipse safety here.

Those of us who grew up in the last century (context: it was only 18 years ago) learned a cool - and cheap - trick for viewing solar eclipses: make a projector. Instead of looking at the sun, you project the sun's image on a sheet of paper (or a white wall) and watch the moon move across the sun's image. The easiest projector to make is a pinhole projector.

How to make a pinhole projector: Find a piece of cardboard in your recycling bin (clean pizza box, cereal box, large postcard, old spiral notebook cover, even a couple paper plates). Then use a thumbtack, nail, or even sharp point of a pencil to poke a small hole through it. With your back to the sun, hold the cardboard over your shoulder and project the image onto a piece of paper on the ground or a white sidewalk.

Eclipse Science: 

What is the best size or shape of hole for a projector? The suggested size for a pinhole is 1mm, with a perfectly round hole. Will larger holes project just as well? Punch or cut a series of holes of different sizes so you can compare them during the eclipse. Which ones provide clear images? Which provide fuzzy images?

Does hole shape matter? What if you cut a triangle or square?

Does distance of your projector from the ground matter? Compare images when you hold projector close to ground, knee distance, waist distance, shoulder distance... attached to the handle of a rake and held high above the ground...

How does the world change during a solar eclipse? Before the eclipse make some notes about the temperature, how the air feels on your skin, what the surrounding environment looks like, what bird and insect sounds you hear. Continue to jot down observations as the eclipse progresses, and especially when it reaches its darkest. 

More projectors: Got a cereal box? You can turn it into an eclipse viewer with a minimal amount of materials and time. Here's how. Or try making an eclipse viewer from a tube. Instructions here. (Experiment: does tube length matter?)

Remember: it's summer, so put on your sunscreen because you can get a sunburn even during an eclipse.

Super Moon, Eclipse, and Space Books

Sunday night will be special - not only is it the night of the full harvest moon (a "super moon" no less) but it's also a chance to see a complete lunar eclipse. The moon orbits around the earth in an imperfect circle, so sometimes it is far away from the earth and sometimes it is closer. This fall, the moon is closest to the earth, and so the full moons look bigger that usual. People call them "super moons".

Something else cool is happening, too: this coming Sunday night is a lunar eclipse. An eclipse happens when the moon passes through the earth's shadow. If you're in the eastern part of the US, head outside around 9 pm and watch the moon. Here's more about the lunar eclipse - or you can click on the poster.

Earth isn't the only planet in our solar system that has a moon - Saturn has more than 50 moons, and Jupiter has at least 67. Makes you wonder what a "super moon" or eclipse would look like from one of those planets.

Speaking of Saturn and Jupiter... Capstone has just published a new series called "Smithsonian Planets". Got questions about where the fastest winds in the solar system are? Whether people are going to Mars? What Saturn's rings are made of? Then you'll want to read about "The Secrets of Jupiter" and all the other planets: Earth, Mars, Mercury, Neptune, Saturn, Uranus, and Venus.

(What about Pluto, you ask? As you might recall, Pluto was determined to be "too small" for regular planet-hood, so is now considered a dwarf planet or Kuiper Belt object - even though it has plenty of moons of its own.)

The Secrets of Saturn
by Kassandra Radomski
32 pages; ages 7-10
Capstone Press, 2015

What I like about the books in this series is that they begin with some basic info about the planet: distance from the sun (886 billion miles for Saturn), number of moons, day-length. On Saturn a day is 10 and a half hours, but it takes 29 Earth years to make one complete orbit around the sun. So winters would be really long.... great for skiers, though how one would ski on a gas giant is anyone's guess.

Then there's the wind: at Saturn's equator, wind speeds reach up to 1100 miles per hour. Compare that to the fastest wind on Earth, 246 mph, and that was during a hurricane. Kids will learn a lot about the planet, moons, and history of ancient astronomers in this photo-rich book. The text explains concepts well in kid-friendly language, and there's lots of fun stuff: a timeline of Cassini mission, a scientist spotlight, speculation on what scientists will find next.Here's the latest news from Saturn.

Future space cadets might be interested in Enslow's new "Launch into Space" series. These books explore the earth, moon, stars, solar system and the sun. Here's one I like:
Astronauts Explore the Galaxy
by Carmen Bredeson
32 pages; ages 7-10
Enslow Publishing, 2015

The book opens with some introductory information about astronauts, with each page focusing on one aspect: free fall, what jobs they do, space walking. What do they eat in space? Apparently the same stuff I eat for lunch, only packaged differently - and there's a great photo of some of their food. You learn how astronauts brush their teeth, use the toilet, and keep their muscles in shape. There's even some tips for astronauts to be.

Today's review is part of the STEM Friday roundup. Drop by STEM Friday blog for more science books and resources. Review copies from publishers.