Click on an experiment: Experiment #1ó Heat Energy Experiment #1--Heat Energy: Question:Ý How much heat energy is in a substance? Background:Ý The foods we eat give off different amounts of heat energy.Ý Other substances also give off different amounts of heat energy when they burn. Materials:Ý cork, matches, needle, thermometer, test tube, test-tube holder, assorted substances (bread, bacon, potato, paraffin, piece of cloth, piece of wood, wad of paper). Procedure:Ý Place 50ml of water in a test tube.Ý Measure the temperature of the water with a thermometer.Ý Take a small sample of bread and stick it to the blunt end of a needle.Ý Stick the needle with the bread in a cork.Ý Put the cork on a tabletop.Ý Use a match to set the bread afire.Ý Once ignited, hold the test tube with water above the flame.Ý CAUTION:Ý Be careful when you are working with an open flame.ÝÝ When the flame goes out, measure the temperature of the water in the test tube.Ý Keep a record of this temperature.Ý Repeat the procedure for each substance. Upon completion, answer these questions:
Click here when you are done with this activity Experiment #2--Properties of Water: Question:Ý Which explanationóthe tiny-opening hypothesis or the kinetic-molecular theoryóbest explains the kind of liquid that forms on the outside of a glass? Background:Ý The tiny-opening hypothesis may be used to explain where drops of liquid on the outside of a glass come from.Ý The tiny-opening hypothesis predicts that the liquid on the outside will be the same as the liquid on the inside.Ý The kinetic-molecular theory may also be used to explain where drops of liquid come from.Ý But the kinetic-molecular theory says that the liquid on the outside will be water, no matter what is inside the glass.Ý To find out which explanation best explains where the liquid comes form, you can do an experiment to test the prediction made by each explanation. Materials: 4 glasses, salt, sugar, soda pop, vinegar, ice cubes. Procedure:Ý Put water in two glasses.Ý The first glass should have salt mixed into the water.Ý The second glass should have sugar mixed into the water.Ý In a third glass put soda pop, and in the fourth glass put vinegar.Ý Add four ice cubes to each of the four glasses.Ý Taste the liquid in each glass.Ý Write down a description of each taste. After a minute or so, drops of liquid will form on the outside of the glasses.Ý You can readily observe the drops that form on the glass.Ý When drops form on the outside, taste them.Ý Record the taste for each glass next to the descriptions of the tastes of the liquids in the glasses. Upon completion, answer these questions:
Click here when you are done with this activity Experiment #3--Bacterial Growth Question:Ý How effective is mouthwash against bacterial growth? Background:Ý Bacteria are found almost everywhere on your body, including your mouth.Ý Advertisements for mouthwashes claim to kill bacteria because, they say, the mouthwashes are antiseptic.Ý An antiseptic is a substance that slows or stops the action of microorganisms. Materials:Ý bacterial culture, 5 small jars, graduated cylinder, 4 different mouthwashes, medicine dropper, 250-ml beaker, Sharpie pen. Procedure:
Upon completion, answer these questions:
Click here when you are done with this activity Experiment #4--Effect of sunlight on moss growth rates Question:Ý How does direct sunlight affect moss growth? Background:Ý Mosses are nonvascular plants.Ý Because mosses do not have vascular tissue, they are not able to grow very large.Ý Most mosses are only a few centimeters tall.Ý Some places where mosses grow are in sidewalk cracks, along the sides of buildings, and at the base of trees in a forest. Materials:Ý 4 clumps of fresh moss, 4 medium-sized paper cups, soil, scissors, hand lens, water. Procedure:Ý
Click here when you are done with this activity Experiments 1-4 are based on experiments found in the following sources: Bernstein, L.Ý (1999).Ý Globe Biology.Ý Upper Saddle River: New Jersey, 671pp. Magnoli, M.A., Shymansky, J.A., Blecha, M.K, Holly, J.C.Ý (1985).Ý Experiences in Physical Science.Ý Laidlaw Brothers: A Division of Doubleday & Co., Inc., 592pp. |
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