The next few days are also good times for viewing the Geminid meteor shower, with peak shower activity expected on December 13 and 14, 2011. Moonlight may interfere with viewing at certain times.

Tips:
1. Try to find a place that is dark for best viewing. Porch and street lights can fade out the meteors.
2. Remind your children there may be several minutes between sightings. In the wee hours of the morning it can be hard to be patient.
3. Blankets and lawn chairs that allow for viewing in a prone position help prevent neck strain and keep chilly viewers warm.

Once again, EarthSky has more detailed information.

This Tonight’s Sky video has even more objects to look for in the December 2011 skies.

If you do go out and observe some of these, I would love to hear what you see.

For example, radar and radio waves were used to investigate the recent asteroid that passed by the Earth.

To help understand how all this works let’s explore the different types of radiation found in the electromagnetic spectrum. We split the activities into two posts because it is rather long. In Part 1 we started an electromagnetic spectrum wall chart, examined waves/wavelengths, and radio waves. Now let’s find out more.

Part 2 Electromagnetic spectrum activities:

1. Microwaves

Because of microwave ovens, microwaves have become a household word. But what are microwaves and how do they work?

Microwaves are a form of electromagnetic radiation with wavelengths shorter than radio waves. They are used for all sorts of things, including remote sensing of weather for forecasting, as well as for monitoring space. Some forms are also used for communications.

In the microwave oven, substances containing water molecules absorb microwave energy and heat up.

This simple experiment from Steve Spangler is sure to get kids excited about microwaves.

Physics in the Microwave at Physics Central explains more and has ideas for “expanding” this experiment.

Microwave information at NASA

2. Infrared

We can’t see infrared radiation with our eyes, but we can sometimes feel it is as heat. Certain snakes, called pit vipers, have organs on their heads that can detect infrared radiation (as a way to find their prey in the dark).

We can see infrared radiation using special cameras. Check out this online infrared photo album Click on “start” in the upper right hand corner to see real infrared photographs. If you click on the special magnifying lens and then move your mouse over the image, you’ll see the same photograph in visible light. Look at the footprints. Where did they go in the visible light view?

If you have a Macintosh computer, you can fake an infrared photograph using the program Photo Booth. See if you can figure out how the program achieves this effect.

For more about infrared radiation, see:

Herschel and his discovery of infrared

The James Webb Space Telescope will detect infrared.

Science Buddies has a new infrared telescope project that you can build based on the James Webb Space telescope

Learn about your TV Remote (infrared signals).

Information about infrared at NASA

(Image from NASA)

3. Visible Light

Gather:

• prism or glass of water

Take it outside on a sunny day and create rainbows by separating white light into its component colors. (See related post for more information and activities).

If you don’t have a prism, Catch The Waves has a color spectrum interactive you can try online.

Demonstration that light waves are a form of energy:

A radiometer can be used to show that light is a form of energy. Place the radiometer in a sunny window and watch the blades/panels inside spin. Energy is the ability to do work, in this case moving the blades.

You can also convert light energy to heat energy by concentrating it with a magnifying lens. Have you ever burned a piece of paper with just sunlight and a magnifying lens? (Only with adult supervision.)

4. Ultraviolet (UV)

Ultraviolet radiation has a slightly shorter wavelength than visible light. Humans can’t see ultraviolet light, but many other animals can, including honey bees and butterflies.

Many flowers have spots we can not see in visible light, but that show under ultraviolet light. Scientists call these spots and patterns “nectar guides” because they are thought to attract bees and other pollinators to the flower.

(Photograph is from Wikimedia Commons.)

Exploring ultraviolet:

a. Obtain or borrow an “black light” (available in many hardware and home supply stores). Black lights produce a type of UV light. Materials, such as florescent posters, glow under a black light. Try out the activities in this glowing chemistry post.

Some items that glow under a black light:

• Did you know that ripe bananas glow blue under certain ultraviolet lights?
• Scorpions glow when you shine a black light on them in the dark.
• Certain minerals also glow under UV. See some examples in this short video:

b. Gather some ultraviolet-sensitive beads (see below for one source) that change colors when expose to ultraviolet radiation. Find out whether you have to be in direct sunlight to be exposed to ultraviolet radiation. (We found that there was enough reflected UV in some shady places to color the beads.)

Saturn’s Rings in ultraviolet light (Image from NASA)

Ultraviolet information at NASA

5. X-rays

Have you ever had an x-ray taken, for example at a dentist’s office or if you had a broken bone? X-rays are a form of electromagnetic radiation with a very short wavelength.

X-rays are considered to be “ionizing radiation,” which means its energy levels are high enough that when it strikes a molecule it can remove an electron, thus forming an ion. Because of this property, exposure to X-rays should be limited.

X-rays at NASA

6. Gamma rays

Certain gamma rays have the highest level of energy of all the forms of electromagnetic radiation, as well as the shortest wavelength. Here on earth gamma rays are only produced by lightning, radioactive decay of certain radioactive elements, and nuclear explosions. In space they are produced by high-energy events such as supernovas.

Gamma rays are harmful and helpful because they are used to treat certain cancers and to kill bacteria in food.

Gamma Rays at NASA

Light and its relatives in the electromagnetic spectrum have a lot of uses, including investigating space. Have you used any forms of electromagnetic radiation today? Leave a comment and let us know which ones.

(If you purchase an item at Amazon through these links, I receive a small commission that is used to offset the costs of maintaining this website.)

To celebrate, I am going to have a post with recently-published science books every day this week.

Our books today are What Do We Know About Stars & Galaxies? by John Farndon
and Milky Way and Other Galaxies (The Solar System and Beyond) by Megan Kopp are excellent introductions to all the new discoveries that have been made about galaxies: how galaxies form and how they behave. (See Wrapped in Foil for a full review of the books.)

How do scientists study objects in space? Modern astronomers use a variety of telescopes to capture information about the universe. Often the telescopes are part of orbiting satellites in space. Megan Kopp’s book, in particular, covers the technology that is used to study galaxies. She talks about the Hubble Telescope, the James Webb Telescope, the Spitzer Space Telescope, and the Alpha Magnetic Spectrometer-2, affectionately known as the AMS-2.

The telescopes monitor light and/or its relatives, that is, light and other forms of radiation in the electromagnetic spectrum. To help understand how all this works let’s explore the different types of radiation found in the electromagnetic spectrum. We will start with an introduction to the electromagnetic spectrum and radio waves. Expect more about the different forms of electromagnetic radiation over the upcoming weeks.

Activities:

Illustration from NASA

1. Create an electromagnetic spectrum wall chart.

Use a wall chart to record you observations about each type of radiation.

Gather:

• a roll of paper about five to six feet long (butcher’s paper works great)
• colored markers
• tape to fix the paper to the wall (painter’s tape won’t leave a mark)
• yardstick (optional)
• an example of the electromagnetic spectrum

Study the example of the electromagnetic spectrum. Write the names of the different types of radiation from left to right across the center of the paper in order of size of wavelength: Radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma rays. Then have the children add information to the chart under each type as you learn more doing the activities.

2. What is a wave?

You may have read that light and its relatives travel in waves. What does that mean?

Think about physical waves, like the waves in the ocean or sound waves. Electromagnetic waves exhibit a similar motion.

Check this very fun interactive website to see how you can vary the wave with different motions. Then give it a try. Gather a jump rope or other heavy rope. Have two children hold each end to the rope tightly. Now have one move the rope up and down while the other stays still. Can you create a wave motion? What happens when you speed up or slow down? How about if you move your arm higher or less?

Find out more about electromagnetic waves at NASA.

Now we will look at different types of electromagnetic radiation, starting at the radio waves, which have the largest wavelength and low energy, to gamma rays, which have the smallest wavelength and highest energy.

3. Radio waves

Have you ever wondered how radios work? How does electricity and sound waves become transmitted through the air via radio waves?

How Radios Work from NPR

Radio Wave Lesson Plans

Radio waves at NASA

Control a radio telescope from the classroom

Currently the largest telescope to detect radio waves from space is the Arecibo Radio Telescope in Puerto Rico.

Studying the electromagnetic spectrum helps us understand more about astronomy, as well as other fields like communication and medicine and it is really too much for a single post. I will link to posts about microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays as they are published.

Edit: Part 2 is now published.

Our books today:

Earth Space and Beyond: What Do We Know About Stars & Galaxies? by John Farndon

Hardcover: 48 pages
Publisher: Raintree
Language: English
ISBN-10: 1406226289
ISBN-13: 978-1406226287

What Do We Know About Stars & Galaxies? Express version by John Farndon

Reading level: 3 (simpler version for younger children)
Library Binding: 48 pages
Publisher: Heinemann-Raintree (August 1, 2011)
Language: English
ISBN-10: 1410941620
ISBN-13: 978-1410941626

Milky Way and Other Galaxies (The Solar System and Beyond) by Megan Kopp

Reading level: Ages 9-12
Paperback: 32 pages
Publisher: Capstone Press (August 1, 2011)
Language: English
ISBN-10: 1429672277
ISBN-13: 978-1429672276

Books were supplied by the publisher for review purposes.

This video from NASA (has an ad) will explain more.

If you miss the Draconid shower or it doesn’t turn out to be much of a show, try the Orionid meteor shower which is supposed to peak in the early morning of October 20 and 21, 2011. Unfortunately, the brightness of the moon may interfere.

Tips:
1. Try to find a place that is dark for best viewing. Porch and street lights can fade out the meteors.
2. Remind your children there may be several minutes between sightings. In the wee hours of the morning it can be hard to be patient.
3. Blankets and lawn chairs that allow for viewing in a prone position help prevent neck strain and keep chilly viewers warm.

More information at EarthSky

Leave us a comment and let us know what you see.

Photograph from NASA by Vincent Jacques

NASA image courtesy MODIS Rapid Response Team at NASA GSFC. Caption by Michon Scott.

For the second time this week we have space-related activities. First it was the Plants in Space project on Tuesday, and now it is time for World Space Week.

World Space Week is held from October 4-10 each year, and it is a perfect time to get your children/students/future astronauts excited about Astronomy. Why October 4? That’s the day that Sputnik was launched into space in 1957.

Of course I went right for the educator’s area on the website, and I found some treasures. For a free download of twenty-six pages of great activity ideas for children of all ages, check out the 2005 global edition (in English) of the Teacher Activity Guide

On the same page, the ESA edition (ESA= European Space Agency) is older version. Although some information is dated, it is 15 pages and student activities start on page 7. How can you go wrong with a title like “Eggnaut – or Houston we may have an Omelet.”

The website also has an extensive list of education links, including BBC Space and Lance’s Lab, where children are challenged to design a space station module for musician Lance Bass to live in space.

The event search will help you locate related events in your area. In Arizona there will be a series of free lectures at Arizona State University this week. Look for stories in your local news media, as well.

I particularly enjoyed seeing what other children are doing to participate throughout the world via the World Space Week Photostream on Flickr. What a golden opportunity to sneak in a geography lesson, so have an atlas handy.

I’d love to hear how you celebrate  World Space Week.

Through the wonders of YouTube, here is Peter Nugent to tell you about it himself.

Although he says you can see it with binoculars, EarthSky says you will have a better chance with a small telescope in “Top 10 tips for seeing the supernova.”

If you live near San Francisco, you might want to find out about visiting the Chabot Space and Science Center on September 10, 2011 for a viewing through a big telescope (weather permitting).

Our weather forecast indicates a lot of clouds over the next few days. Let us know if you get to see it.

The exact times are Monday December 20, 2010 starting at 11:33 p.m. through Tuesday December 21, 2010 at 3:01 a.m. AZ time (that is 1:33-5:01 a.m. Eastern)

It’s a great learning opportunity for your children.

There are related activities for kids and information from NASA’s Jet Propulsion Laboratory. The movie that shows how solar and lunar eclipses occur is helpful. You might want to build your own model.

NASA Science has general information plus links.

Mr. Eclipse has extensive, detailed information about the lunar eclipse, as well as some spectacular photographs.

If the weather is clear, try looking at the moon tonight. If you have binoculars or a small telescope, try those too.

The most obvious features on the face of the moon are the dark circles of impact craters, where meteorites and other space debris have hit the surface. It might be time to re-visit an old standby activity. Your children can create and study craters with a few simple ingredients.

Gather:

• two types of flour of different colors (check in the back of the cupboard for something that has gone stale)
• a large cake pan or other deep pan (preferably unbreakable) or even a shoe box
• hard rubber balls or round rocks to act as meteorites
• stable step stool, stepladder or chair (optional)

Note: Often instructions for this activity (like the video below) use cocoa powder, but I found that can be expensive. A whole wheat flour and a white flour will work just as well. You can even see the results with one type of flour, although perhaps not quite a clearly.

Fill a large cake pan or other deep pan (preferably unbreakable) halfway with colorful flour, such as whole wheat or corn meal. Then gently add a layer (an inch or so) of white flour over the entire surface.

Take the flour container outside, if possible, and set it on a low, flat surface. Have your kids stand on a secure chair or stepladder and drop various round objects into the flour. The results should be some interesting craters and splash patterns, which are the patterns of debris shot out of the crater with impact.

You should see something like this:

Any ideas why the moon has so many visible craters where the earth does not? There are actually at least two reasons. See if you can think of them.

Check Enchanted Learning for more details about lunar craters.

Let us know if you get to see the lunar eclipse.

For more information on astronomy, try:

Tips:
1. Try to find a place that is dark for best viewing. Porch and street lights can fade out the meteors.
2. Remind your children there may be several minutes between sightings. In the wee hours of the morning it can be hard to be patient.
3. Blankets and lawn chairs that allow for viewing in a prone position help prevent neck strain.

Here’s an informative video about last year’s shower:

More tips for watching meteor showers from NASA

Let us know what you see.

Northern Lights, also known as Auroras, occur when ions in the form of solar wind from the sun strike the gases in the upper atmosphere of the earth, causing them to glow. The glow typically occurs around the Arctic Circle, but large flares can cause a glow that can be seen throughout Canada and into the northern United States. Here is a photograph taken in Wisconsin.

Photo from NASA Images

Links to sites with more information and photographs  (As usual, please check the links for suitability before showing to your children, as the content may have changed):

Spaceweather.com has the newest predictions and archives of photographs.

Incredible Flickr photographs

Article with information on sightings

We hear a lot about the Northern Lights. Are there Southern Lights?

Answer here.

Dr. Geoffrey Marcy is an astronomer who hunts for planets around stars other than our sun. He and his team have found about half the planets discovered thus far.

According to the book, Dr. Marcy became interested in outer space when his parents gave him a telescope at 14. He climbed out the window to the patio roof with it. One look into the night sky, and he was hooked on astronomy.

Dr. Marcy pioneered a technique to look for planets that involves the use of a spectrometer, which gathers and measures light from stars. Let’s celebrate the book by taking a look at some of the science behind his techniques.

1. Activity:  Make a rainbow

One of the easiest ways to study how the light we see is made up of a mixture of colors (or light of different wavelengths), is to create a rainbow using water.

Robert Krampf has a video to show us how with a hose. (If you have never tried his Happy Scientist website, it is well worth a visit.)

Another device that can be used to separate light into its component colors is a prism.

This prism is made of glass. You can find them at teaching or science supply stores. When the light passes through it, we can see this on the ground:

For best results I put a piece of white paper on the ground in a shaded area, and held the prism about three or four feet away in the direct sunlight. With practice you can find and direct the resulting rainbows by rotating the prism.

If you don’t have a prism, the grooved side of a CD can separate colors in light as well. CD’s act as what are called “diffraction grids.”

2. Activity:  Make your own spectrometer from a cereal box. (Requires adult assistance)

What is a spectrometer? Is it different from a spectrophotometer?

A spectrometer is a device that gathers light from a source and divides it into a spectrum by passing it through a medium. Those used for astronomy would have a telescope to gather the light, some sort of device to separate the colors – such as a prism or diffraction grid – and a detector to record the results. Sometimes gases or solutions are added for the light to pass through to help gather additional information about the characteristics of the light.

There’s a more detailed explanation at How Does a Spectrometer Work?

A spectrophotometer is simply a specialized spectrometer that works with light near or in the visible spectrum for humans.

To make a spectrometer using a cereal box,

Gather:

• an empty cereal box
• sharp knife (ask an adult to help with this part)
• empty rewritable CD
• masking tape
• scissors

Seal the top of empty cereal box with masking tape, so no light can enter. Lay the cereal box on one of its narrow sides. Ask an adult to cut a slit across the bottom of the box, about 1 inch down from the top side. Some of the instructions suggest reinforcing the slit with masking tape. Ours worked okay without doing that, but if your box tears, you will need to fix it.

Take a look at these websites for additional diagrams and information:

A fresh look at light: build your own spectrometer

How to Make a Color Spectrometer From a Cereal Box & CD
at eHow (site has ads)

Leaving the box on its side, turn it to the other end. Have an adult cut a diagonal slit at about an 60 degree angle from the top, towards the middle of the box. This groove will hold the CD at an angle. Then cut the CD in half with the scissors so it will slip into the groove. Be careful, the CD may shatter. Put 1/2 the CD in the groove, shiny (reflective) side up.

The last step is to cut a viewing window. With the CD in place, cut a square opening at the same end of the box so that you can look down onto the tilted CD to see the colors.

To test your spectrometer with a flashlight, take it into a room that can be made dark. Turn the flashlight on to shine into the light slit and then turn off the room lights. Look into the viewing hole. If you don’t see a rainbow of colors, adjust the flashlight and or the angle of the box until one appears. You may now want to check the color spectrum of other light sources.

3. The Doppler Effect

When Dr. Marcy and his team study the light from stars, they are looking for evidence that the star is wobbling due to the presence of a nearby planet. Evidence of wobble comes from shifts in color due to the Doppler Effect.

Here is a video that explains how the Doppler Effect works.

Wasn’t that fun?

Next time you hear about a new planet being discovered some distant star, think of Dr. Marcy and his team. And if you know a child who is interested in science, particularly astronomy, then you should check out this inspiring book.

Book supplied by author (see disclosure page).