Set an ice cube on a metal pan and another on a wood block inside the classroom. Have students predict which material will make the ice melt faster. Repeat the experiment outside in the sunlight and have students observe the changes in how the ice melts. When students finish the experiment explain to them wood is an insulator and metal is a conductor. Have them name the characteristics of conductors and insulators when the ice was melting inside. Then have them make a conjecture about how the sun affected the results of the experiment.
Mix 1/2 cup of salt in a gallon of water. Pour in large open-mouth container. Set pieces of different kinds of wood (pine, oak, cherry) and metal (foil, copper pennies, nickles). Wait one week to see what has happened to the wood and metal. Record and write about your results. Explain to students the concept of corrosion. Have them speculate which material would be better to use in the ocean.
When building structures of metal and/or wood, engineers need to figure out how a structure will react to the chemicals in the environment around it. For example, to test the effect of acid rain, repeat Section 2, using a mixture of vinegar and water instead of salt water. You can also test oil, lake water (filled with organisms), and mud (mixing soil with water).
Wrap an ice cube in five layers of newspaper and another ice cube in five layers of aluminum foil. Set aside for an hour. Open the foil to see how much of the ice cube has melted. Then open the newspaper. Compare the size of the two ice cubes. Explain to students the concept of insulation and insulators. Explain to them that newspaper comes from wood and aluminum is a metal. Finally, have them write a conclusion as to which is the better insulator, wood or metal.