Cling film science projects introduce students to several concepts, including elasticity, heat conduction and static electricity. The wrap's molecules are long and tightly coiled. When you pull it in different directions, the wrap's molecules stretch. Cling film can absorb an electric charge via friction. Electrons scatter, causing a negative charge. The surface covered with the wrap is positively charged, accounting for the cling when you wrap a dish.
Compare which type of wrapper--plastic wrap or aluminium foil-- provides better insulation for cold water. Gather three conical flasks, three corks, three thermometers, roll of aluminium foil, roll of cling film, measuring cylinder and an electric drill. Drill a hole in each cork the same diameter as a thermometer. Thread the thermometers through the corks. Fill the flasks with the same amount of ice water. Seal them with corks. Adjust the thermometers so the ends just brush the water. Wrap one flask with 10 layers of foil and the other with 10 layers of cling film. Keep the third flask uncovered as a control. Track and record the water temperature in all flasks in 30-minute intervals for two hours. Determine which wrap provides superior insulation. Explain your conclusion in terms of heat conduction and heat loss.
Gather three samples of three polymers, such as polyvinylidene chloride (Saran Wrap), polythene (Glad Wrap) and polyvinyl chloride (Reynold's Cling Film), used for cling films to test which best prevents evaporation. Line up nine identical glass cups in three rows of three cups each. Wrap the cups in each row with one type of polymer. Seal each glass with a rubber band, mark the water level and label them accordingly. Track and record the differing water levels in the glasses. Research the polymers to explain the permeable natures of each polymer. Repeat the experiment, placing the glasses within a different temperature, such as the refrigerator.
Gather the same polymers in the evaporation project, but test to see which polymer is the least permeable to air or oxygen. Cut enough apples for twelve slices. Wrap three slices for each type of polymer. Set aside three slices unwrapped as a control. Check the slices at unvarying intervals and record the oxidation process. Take pictures as evidence. Repeat the experiment, but place the apple slices at a hotter or colder temperature. Test whether stretching the cling film affects the oxidation rates by covering the apples tightly in shallow dishes.
Gather three materials with different elasticity, such as strips of cling film, curling ribbon and electrical tape. Measure and mark a space of 5cm in the centre of a material with high elasticity and a space of 10cm for a material with low elasticity. Measure the width and thickness of each material. Attach one end of the material to a metal rod clamped to a ring stand. Secure the stand with weights. Attach a 50g weight to the other end of the material. Measure the distance between the marks, recording any elongation that may occur. Add more weight at regular intervals. Measure the elongation until the material breaks. Calculate the stress or force versus the elongation for each material and graph your results.
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