The data from measurements of the density of tungsten, steel, aluminum, and PVC spheres are used to extrapolate the infinite density of something such as a neutron star. An apparatus that allows for precision measurements is described. A discussion on error analysis is appended. (KR)

An activity in which students use a rubber band and flexible straws to pull a dynamics cart so that the cart has a consistent angle and, therefore, a consistent horizontal component of force is described. A copy of the handout for the activity is included. (KR)

Situations describing Einstein's Equivalence Principle phrased in prerelativistic Newtonian concepts are presented. (KR)

Described are how invitations to inquiry have been used in presentations to effectively demonstrate and explain the notion of inquiry and its role in science teaching and how they can be used in teacher education. An initial segment of an invitation to inquiry script and a list of topics that have been used as invitations to inquiry are included.…

Activities in which students can learn to determine the history of a tree from the growth pattern recorded in the rings of a cross-section of a tree are described. Activities include background information, objectives, a list of needed materials per group, and procedures. Cross-sections of four different tree types are included if real tree…

Advice on how to transform a practical idea into a first-class science fair project is provided. How to do scientific research, what to include in a science fair report, how to pick a topic, when to begin, writing the report, and making the display are topics of discussion. (KR)

Describes how electrochemical cells exploit reduction-oxidation (redox) reactions to produce electric current. Presents an activity using a paper clip, copper wire, an apple, and a voltmeter where students can measure the voltage from an apple cell. Describes variables that can be changed to assess the impact on the voltage produced. (PR)

Presents hands-on science activities that help students learn the concepts of hearing and sound while allowing students to practice science process skills. Students investigate the use of alternative phonograph speakers and needles and apply the knowledge learned to the construction of one-string banjos. (MDH)

Describes the life cycle of the Amaryllis plant from bulb to blossom. Suggests 12 activities in which students monitor plant growth, examine plant parts, make drawings of the plant, and eat flowers of other plants. (MDH)

This form is used as a measurement of student's on-task activities. It indicates the incorporation of science skills into each individual student's repertoire and provides a record of the activity to assure parents, board members, and teachers that learning is taking place in the classroom. (PR)

The simple physics behind the mechanism of the toy are explained. Experimental and mathematical steps are given that help in understanding the motion of the doll-pair. The geometry of the setup is described. (KR)

An attempt to clarify the teaching of some of the concepts of thermodynamics through the observation of an experiment with an ordinary refrigeration system is presented. The cycle of operation in the refrigeration system and the individual processes in the cycle are described. (KR)

A technique that uses a three-meter Foucault pendulum and a laser to measure latitude is presented. A 40-meter Foucault pendulum located in Finland and the ways in which it is used are described. The technical details and the plans for a continuously driven laser pendulum are discussed. (KR)

Information about the recycling and reuse of plastics, aluminum, steel, glass, and newspapers is presented. The phases of recycling are described. An activity that allows students to separate recyclable materials is included. The objectives, a list of needed materials, and procedure are provided. (KR)

Consumer chemistry projects using houseplant fertilizers are described. Background information on fertilizer elements and different brands are discussed. The procedures for the activities (reading fertilizer labels, calculating the cost of various fertilizers, and calculating the amount of nitrogen in solution) are included. (KR)