December 30, 2009
by: Sarah Brandt
The uniquely entertaining energy ball is a fun way to demonstrate open and closed circuits, as well for prompting discussions on conductivity. The following activities are perfect to use in elementary and middle school grades first exploring electricity and circuits.
When both sensors on the ball are touched and a complete circuit is formed, the ball flashes a red light and buzzes.
What makes the energy ball work?
Inside the energy ball is a simple circuit that is completely self-contained. By touching both sensors, the circuit is completed by electrons flowing through your body or another conductive material such as a paper clip. Materials that activate the energy ball
are good conductors, meaning they pass electrons easily. Materials that do not activate the energy ball are poor conductors (or insulators), meaning they do not pass electrons easily. Read the rest of this entry »
December 30, 2009
by: Tami O’Connor
One of the units I enjoyed most as a middle school teacher was the section on energy. The many awesome hands-on experiments generated such a series of oohs and aahs that it made my already-enjoyable days even more enjoyable! One of my favorites was a lesson that dealt with the Law of Conservation of Energy. A consequence of this law is that energy cannot be created, nor can it be destroyed. (The students would have already explored potential and kinetic energy before the following activity.)
I initiated this lesson reviewing what happens with energy in a closed system. The students clearly remembered comparing the amount of potential energy to kinetic energy using the example that the height of a roller coaster’s first hill is always greater than the height of any of the remaining hills. It is, of course, possible to have a little hill followed by a higher hill as long as the roller coaster is going faster at the top of the little hill than the next higher one. The students were generally able to explain the transfer of energy including heat energy and sound energy in the overall system.
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December 1, 2009
by Tami O’Connor
Invented in 1945 by Miles Sullivan, the “drinking bird” has been a favorite of science teachers in every classroom from kindergarten through college. This amazing device is made of two glass bulbs (one representing the head and the other representing the body) joined by a glass tube (representing the neck). Between the two bulbs, attached to the glass tube, is a metal fulcrum upon which the bird pivots. The air has been removed from this closed device, and the bottom ball is filled with a colored liquid that has a high vapor pressure (methylene chloride). The rest of the bird’s body and head is filled with the vapor form of methylene chloride.
The demonstration is set up such that a glass, filled to the top with water, is placed in front of the drinking bird. The glass should be the same height as the pivot point of the bird. The bird’s head should be moistened and then the bird should be given a gentle push to begin it oscillating along the pivot point. Eventually, the bird appears to drink repeatedly, on its own. So, how does that happen?? Read the rest of this entry »