Tools for appreciating flowers May 26 2015, 0 Comments

I’m going to go off on a tangent before I discuss materials for botany studies with older elementary children. I’ve been researching an important tool for botany studies, a hand lens.

A hand lens (aka pocket magnifier) is very useful for botany studies. Many flowers have parts too small to see without magnification, and there are even whole flowers that are too small to see without this help. Regular magnifying glasses are usually 2-3X magnification, but what you need for botany is something in the 4X to 5X range. With that you can see the texture of stigmas and even the larger pollen grains on anthers.

In years past I have been able to purchase 5X glass hand lenses. The lens folded into a plastic case that protected it while it was being carried outdoors. When I tried to find more of these lenses, I found they were no longer available. I searched the Internet, especially Amazon, looking for a replacement and ordered several to try. Here’s what I found.

The only hand lens that had the magnification described on Amazon was the Bausch and Lomb 4X folded pocket magnifier, which cost about $14. I’m now carrying that one in my pocket as my personal lens, but that is a bit pricey for a classroom set. I found that the inexpensive lenses on Amazon were not as advertised. One that was listed as a 4X was actually a 2X. One with glass lenses came with a large scratch on the lens, and its magnification was half of the description. A “bug loupe” that was labeled 5X is actually closer to 3X, and it focuses only when held above the surface, not when resting on its clear plastic housing, which one presumes was there to contain the bug. My basic message: Let the buyer beware when it comes to inexpensive hand lenses.

To tell the magnification of a simple lens, first measure its focal length. You can do this by focusing an image of a light fixture or the scene outside a window onto plain paper. Then you measure the distance between the paper and the center of the lens. If you measured in inches, divide that measurement into 10. If you measured in centimeters, divide that measurement into 25. The result is the magnification. This means that a 5X lens should focus about 2 inches or 5 cm from the paper. A 4X lens should focus at 2.5 inches, and so on.

In the end, I decided that I will have to settle for plastic lenses, although they will scratch easier than glass. Acorn Naturalists has a small 5X lens for about $4, so you can get several for botany or other work. The lens is about an inch in diameter, which is easier for children to use than the narrower 10X lenses. Ten times is more magnification than one really needs, and the short focal length means that you cut off the light as you bend close to look.

With all these lenses, you need to hold the lens close to your eye and either bend down or bring the object up until it is in focus.

I hope this information helps you find the lenses you need for botany and other outdoor observations. If you have found a better alternative, please let me know.

Books for studying your local feathered dinosaurs January 22 2015, 0 Comments

When you are looking for real living things to study and observe in your outdoor environment, the birds of your area can be good subjects even in the middle of winter. Birds are still called class Aves by some scientists, but it is well accepted that they are a branch of the theropod dinosaurs, so they are nested within the Class Reptilia. They are related to the maniraptors, an extinct lineage of small, feathered dinosaurs. The birds that are alive now – the extant or modern birds – belong to the lineage Neornithes. But enough of long names. The real excitement is actually watching birds as they go about their lives.

  Look Up! Bird-Watching in Your Own Backyard by Annette Le Blanc Cate (2013) is a great resource for launching bird studies. This book was the prize-winner in the 2014 book awards from Science Books and Films (SB&F). See http://www.aaas.org/news/2014-aaassubaru-sbf-prizes-celebrate-fieldwork-and-citizen-science . The book encourages children to observe birds and to sketch them. It is illustrated in cartoon style, with the birds making many human-type comments, but elementary children are not likely to confuse the messages from the birds in this book with real bird communications. They will likely find it amusing and engaging, and hopefully it will inspire them to see and learn more about their local birds.

  If you want a more serious look at bird vocalizations, try Bird Talk: What Birds are Saying and Why by Lita Judge (2012). This looks like a good lower elementary read, and it has further information about the bird species shown.

Of course you will need a good field guide to birds so that children can identify the birds they observe. There are many excellent ones available. For the whole US, I like The Sibley Guide to Birds by David Allen Sibley (2000). You may find it useful to have a more local guide as well because it reduces children’s (and adults’) frustration when they are trying to identify a bird they have seen. For a children’s book about a man who pioneered modern field guides, see For the Birds: The Life of Roger Tory Petersen by Peggy Thomas and Laura Jacques.

Children may wish to add their observations to a classroom record, a field guide to their local birds. Will they see the same birds each year? Will the birds change throughout the year? To answer these questions, children will have to observe, identify, record, and see what everyone finds. Happy birding!