Make a solution that will allow students to create very large bubbles. Bend a coat hanger into a more rounded shape and use it as a "bubble wand" by pouring this bubble solution into a cookie baking tray that has a lip around the edge. A good bubble formula is 1 measure of water, 1 measure of liquid dish detergent and one-half measure of glycerin. Determine how much bubble solution you want to make and choose a unit of liquid measure, such as cup or an ounce, and "plug" that measure into the formula.
Perhaps students would like to know how tall that great old oak tree is, but it's too tall to measure, even with a ladder. Using the math concept of comparison relationships, you can get a good idea of its height. Facing the tree, have a student hold a pencil out at arm's length and walk backwards until the top of the pencil is in line with the top of the tree and the bottom of the pencil is in line with the bottom of the tree. Measure the distance from the student's eye to the pencil. Use a tape measure to find the distance between the student and the bottom of the tree. The relationship of these numbers is: pencil length/arm's length = tree height/distance to the tree. Rearranging this equation to solve for the tree height: tree height = distance to tree x (pencil length/arm length). Set up a spreadsheet program to perform the calculation.
Humans can generally hear frequencies from about 20 cycles per second up to 20,000 cycles per second. "Cycles per second" are typically called "Hertz." Musical scales are made up of a patterns of frequencies that repeat. In western music, 12 notes are used to make an "octave," after which the notes repeat only at a higher (or lower) frequency that is a multiple of 2 of that frequency. A commonly used tuning fork for musicians has a frequency of 440 Hertz, and that note is a musical "A." Going one octave higher, the next A note has a frequency of 880 Hertz, which is double the frequency. Connect a microphone to the input of an oscilloscope. Using an electronic musical instrument keyboard, select a sound setting that has few harmonics, such as a flute or recorder. Hold down the A below middle C on the keyboard while adjusting the oscilloscope's sweep until you can stabilize the waveform to show two identical "cycle patterns". Then play an A note that is one octave higher and observe that the oscilloscope waveform pattern now shows four "cycles," a doubling. Do this for each of the 12 notes in the musical scale, showing that multiplying the frequency of a note by 2 creates a note one octave higher and dividing by 2 results in one octave lower.
In a forest, the natural materials that cover the forest floor is called "litter," and it is composed of leaves, needles, twigs, bark and other natural items. When forest litter is dry, it is extremely flammable. A bolt of lightning or the careless tossing of a cigarette or match can start it on fire, and it burns hot, easily setting trees on fire. Litter that retains moisture helps prevent forest fires. Hypothesize that litter composed of pine needles retains moisture better than litter made up of deciduous tree leaves. After a heavy rain, remove a one-foot square, two-inch deep section of forest litter that is made up mostly of leaves and remove a similar section that is composed mostly of pine needles. Weigh each square. Place them on a tray in a sunny location for several days until they totally dry out. Weigh each square again. Determine which material held the most moisture after a rain storm by subtracting the dry litter weight from the wet weight to arrive at the weight of the moisture content in each. Calculate the percent of moisture held in each by dividing the weight of the moisture by the wet weight and then multiplying the result by 100. Do this for both squares to discover which type of litter material, if either, may be more beneficial in preventing forest fires.