Your local electric utility company charges you for the amount of electricity you use. Electrical power usage is measured in "watts." A "kilowatt" is equal to 1,000 watts, and the utility company charges you for every kilowatt you use per hour (referred to as a "kilowatt/hour"). If you operate 10 100-watt light bulbs for one hour, this would use one kilowatt of electricity, for which you will charged the current rate for your area, typically between 10-20 cents. Every night at midnight (or at the same time every evening), record the number on your home's electric meter. Set up a computer spreadsheet program to record the day, date, and end of the day meter reading. Then set up a column that will subtract the previous day's reading from today's to determine the number of kilowatt/hours used that day. Newer electric meters have easy-to-read digital displays, but older ones have a series of dials. To read the dials, read from right to left, showing ones, tens, hundreds and thousands places. When the needle is between two numbers, use the lower number. Record your daily readings for one month, then examine your data and determine on which days of the week your family uses the most energy. Investigate why that might be, and suggest ways to reduce electric usage on those days.
Electricity flows through wires and components similar how water flows through pipes. "Resistors" are small components that "resist" -- or reduce -- the flow of electricity, the amount of which is measured in "ohms." The total resistance of a circuit when resistors are placed in series (that is, in a line) is the sum of the each resistor's ohm value. However, the equation for finding the total resistance when two or more resistors are connected in "parallel" (next to each other with their leads tied together) is: 1/(1/R1 + 1/R2 + 1/R3...), where each resister, R#, is the value in ohms. Connect various resistors together in parallel, calculate the circuit's total resistance and confirm your calculation by measuring with an ohmmeter.
If you flip a coin, the chances are 50/50 that it will turn up heads. But suppose you have flipped the coin five times and the last four times it came up heads. Would you be willing to bet that the next time it will come up heads, or do you think that it would be tails because you know that over time heads and tails will come up about equally? Although there may be a streak of one side coming up more than the other, the more times the coin is tossed the closer to 50 percent the total results will be. The smaller your "sample size," that is, the number of tosses, the less accurate will be your results. The "relative frequency" of heads to total tosses can be expressed as a percent, which should ideally be 50 percent, arrived at by using the equation (number of heads/number of tosses) x 100. Flip a quarter 10, 20, 50, 100, 200, 500 and 1,000 times and calculate the relative frequency of heads for each batch tossed.
Set up a fun and simple spreadsheet program in which a person can enter their weight and the program will calculate how much they would weigh on other planets. Some heavenly bodies are not solid or, in the case of the sun, not possible to stand on, so the results are only for entertainment value. Multiply the person's weight by the following numbers to arrive at their weight on other planetary bodies: Mercury, .4; Venus, .9; Mars, .4; Jupiter, 2.6; Saturn, 1.2; Uranus (same as Earth); Neptune, 1.41; Pluto .6; our moon, .16; our sun, 28. Expand your project by having friends guess their weight, then comparing their guesses to the calculations, then have your spreadsheet program calculate how much in error their guesses are, expressed as a percent.