# Physics & Electricity Experiments for Middle School

Middle school experiments in physics and electricity teach teens concepts that are fundamental to many scientific and engineering careers. These experiments also teach teens about the scientific method and demonstrate the importance of documentation. Teens should conscientiously record the experimental conditions and the results from each condition, and then try to develop conclusions, predictions and formulas from their research. There is no better experience for becoming a scientist or engineer.

Make a battery by sticking two dissimilar pieces of metal into a potato 1. For example, stick a short length of copper wire into one end of the potato and a galvanized nail into the other end of the potato. The acid in the potato takes electrons from the copper wire and deposits them on the galvanized nail. Set an ammeter to measure micro-amps, then connect one lead from the ammeter to the copper wire and connect the other lead to the nail. The ammeter should show that a small current is flowing through it. Experiment with different metals, depths and spacing to obtain the most voltage possible from the potato. Also try other vegetables or fruits, keeping the metals constant.

## Magnetic Fields and Electricity

Middle school students can demonstrate a relationship between magnetism and electricity by passing a magnet near a coil of wire connected to a sensitive ammeter. Wrap insulated copper wire three times around an empty roll of toilet paper, and connect the two ends of the wire to the positive and negative terminals of the ammeter. Pass the magnet back and forth through the coil, then pass it near but outside the coil. Try varying the speed with which the magnet moves near the coil. Increase the size of the cardboard roll -- for example, use an empty container of oatmeal with the top and bottom cut out -- and repeat the experiment. Increase the number of coils and repeat the experiment. Repeat the experiment substituting coated stainless steel or brass "beading wire," and then string for the copper wire; when making these substitutions, try to find cord that matches the copper wire's diameter and coating. How does varying the magnet's location and speed, the size of the roll, and the number and type of coils affect the amount of current produced? Which conditions produce the most current, which produce the least?

## Mass, Friction and Speed

This experiment involves dropping objects down a long narrow slide and recording the time it takes each object to reach the ground. Try dropping different size balls, balls filled with air, unsharpened pencils and cubes down the slide. Try to make the objects go straight down the center of the slide. Repeat your actions after lightly covering the slide with sand, and again after rinsing the sand off the slide -- leaving the slide wet. Which object was fastest, and which was slowest? What effect did the sand and the water have on an object's speed down the slide?

## Seesaws and Weights

Students learn about balance from experimenting with weights and seesaws. Draw one line down the length and through the middle of a 12-inch ruler. Drill seven small holes through the ruler, positioning the holes on the line at 3, 4, 5, 6, 7, 8 and 9 inches. Position a cone under the ruler, so its point goes through the hole at the 6-inch mark. When the ruler is balanced on the cone, experiment with the number and location of weights on the seesaw. For example, if six pennies are located at the 1-inch mark, how many pennies are needed to balance the seesaw if the pennies are placed at the 11-inch mark? How many pennies if they are placed at the 8-inch mark? Repeat the experiment with different cone locations 2. For example, if the cone is located so that its point goes through the hole at the ruler's 4-inch mark, and there are four pennies at the 2-inch mark, how many pennies are needed to balance the seesaw if the pennies are placed at the 9-inch mark? Students should try to develop a formula describing the interaction between cone location, weight location and amount of weight.