Introduces sequoias, the largest tree species, and describes the importance of fires in sequoias' successful reproduction and management of the sequoia ecosystem. (Contains 23 references.) (YDS)

Presents an activity that involves using sponge seedlings to demonstrate the germination process without the usual waiting period. Discusses epigeous versus hypogeous germination, and cotyledon number and biodiversity. (JRH)

Researchers who study the fossil record are seeking to determine whether the impact made by a comet or meteor really did decimate up to half of the life on this planet at the end of the Cretaceous period. Questions whether the extinction of plant and animal life was abrupt, started before the impact, or was a gradual change. (KR)

Describes the Purple Loosestrife Project, an innovative outreach and educational program to provide a biological control of purple loosestrife. Involves cooperation of community, teachers, and students. (YDS)

Describes the construction of an effective plant incubator for classroom use using a five-gallon plastic bucket. (JRH)

Presents investigations of leaf surface wetness that provide ideal opportunities for students to explore the relationships between leaf form and function, to study surface conditions of leaves and plant physiology, and to make predictions about plant adaptation in different environments. Describes simple procedures for exploring questions related…

Discusses methods for plotting rates of photosynthesis as a function of light quantity. Presents evidence that suggests that empirically derived conversion factors, which are used to convert foot candles to photon fluence rates, should be used with extreme caution. Suggests how rate data are best plotted when any kind of light meter is not…

The fish poisons derived from plants used throughout the world, not only as piscicides but also for a range of other uses, including insecticident and in folk medicines, is presented. The aim of this review is to provide a useful background for students interested in natural products.

A member of a related genus of the valerianaceae, Centranthus ruber, is used, that yields a higher percentage valtrate than other related species such as "Valeriana officinalis," there by making easier isolation in pure form.

A study was conducted to prove that a large blood or xylem vessel could conduct 256 times more fluid than a vessel or a pipe that is four times smaller. The result of this study proved that if arteriosclerosis causes an artery to loose half its effective diameter, the blood flow would be reduced by fifteen-sixteenths.

The water absorption in chickpeas (dried legumes) is analyzed. The chickpea experiment serves as an introduction to the concepts of osmosis, mass transfer and diffusion.

In this article, the author describes how she introduced the mola designs of the Kuna people of the San Blas Islands to her fifth grade class. The students became excited by the tropical imagery; the wildlife, intertwined with the flowering plant life and the ocean, in colorful and black and-white patterns, because it brought forth such…

Thematic topics offer tremendous potential for science learning in the early grades and beyond. One second-grade class explored honeybees, a subject their teacher found both fascinating and easy to connect to a number of learning standards and science concepts. Her unit, "Honeybees and Apple Trees: A Close Look at Nature's Balancing Act," explored…

Most history books for children focus on people, places, and events. In a different approach, some authors focus on an object--an everyday item that might be ignored when it comes to writing history. They shine a spotlight on the item, and in the process, they add insight and interest to human history. This article looks at four outstanding books…

Just imagine the excitement in the classroom when Johnny Appleseed strides in. Barefoot and dressed in a burlap sack, he-well, actually, it's you dressed up as Johnny-wears a tin pan for a hat and smiles as he relates the reason for his visit. Fall is apple season, and he's here to explain how all the beautiful fall apples were produced. The story…