BROWSE for Homeschooling & Learning

 Real Science—Lipper—Spring 2008 How Things Work: A Sneak Peek at Energy  By Aurora Lipper Every object on Earth is held together by at least one of the four fundamental forces of nature: the strong force, the weak force, the electromagnetic force, and gravitation. These four forces are found within all atoms, and they dictate the interactions between individual particles and the large-scale behavior of all matter throughout the universe. Since the first two forces (strong and weak) require the use of a nuclear power plant, we’ll focus on the other two forces (electromagnetic and gravitation). Gravitation is the force that is always attractive (never repels or pushes away). This is the force that pulls matter together and keeps your feet stuck to the sidewalk. Gravitation causes comets to be slung through our solar system, binds the moon in its orbit around the Earth, and is the sworn enemy of major league baseball pitchers everywhere. The reason you get a shock by scuffing along the carpet can be explained in the realm of the electromagnetic force. This force determines how electrically charged particles interact and is either attractive or repulsive. Identical charges repel each other (two positive or two negative charges). Electromagnetic force is the source of power used in blenders, dishwashers, aircraft engines, solar flares, and lasers—and is a culprit in bad hair days worldwide. The conservation of energy is the idea that “you get out what you put in.” When you fuel your vehicle with gas or electricity, that energy is converted into work you can see (e.g., the car cruising down the road), as well as things you may not notice (heat from the engine, headlights, sound energy, recharging your electrical battery, and so on). We use complicated machines such as a car’s engine to convert energy from gasoline into work, but there are many simpler ways we can see energy at work. Machines don’t need to be as complex as the internal combustion engine—chances are you use several simple machines every day in your home.
 Science Activity: Simple Tug-of-War Pulley System Have two people face each other and let each hold a smooth pipe or strong dowel (at least 18 inches long) horizontally straight out in front of his chest (you also can use broomstick handles). Tie a length of strong nylon rope (slippery rope works best to minimize friction) near the end of one dowel. Drape the rope over the second dowel, loop around the bottom, then back to the top of the first dowel. Zigzag the rope back and forth between the two dowels until there are four strings on each dowel. Attach a third person to the free end of the rope. Thread a 6-inch length of PVC pipe onto the end, and tie the rope back onto itself to form a handle. The two people holding the dowels will not be able to resist the pull when you pull on the end of the rope (the end with the handle)! Science Activity: Simple Balance With a 12-inch piece of rope, suspend a flat ruler (from its center point) from a low tree branch (or stack a big pile of books on a table, place a ruler between books near the top so part of the ruler sticks out, and you can suspend the balance from it). When the ruler is in balance, add identical baskets to each end and place objects in the baskets (or directly on the ruler). Make one basket slightly heavier than the other and slide it toward the fulcrum until the ruler is in balance again. Science Activity: Wedge A wedge is a double-inclined plane (top and bottom surfaces are inclined planes). You have lots of wedges at home: forks, knives, and nails, just to name a few. When you stick a fork in food, it splits the food apart. Make a simple wedge (think ice cream cone-shaped) from a block of wood and stick the point under a heavy block (like a tree stump or large book). If you place a kid on the stump while pushing the wedge, you’ll be able to move them both.  Science Activity: Simple Catapult Use a spoon and a quarter (placed at the end of the handle). Show yourself that the longer end of a lever (spoon handle) travels faster and farther than the shorter end. Think about the position of the fulcrum: What happens when the fulcrum is not at the center?

## Preschool Curriculum

Horizons Preschool Curriculum Kit

Hooked on Phonics: Learn to Read Pre-K Complete

The Weaver Curriculum: Interlock for Preschool and Kindergarten

Big Preschool