OMSI/WinterHaven PSD2000 Project:

Inquiry Sessions | Resources | Teaching Guide

Inquiry Session 2: Environmental Chemistry

Join the WinterHaven students in OMSI's Chemistry Lab as they conduct environmental chemistry experiments from the Museum's award-winning book, Experiencing Chemistry.

Acid Rain | Burning Issues | Cleaning with Charcoal | Foam Peanuts | Take Out the Trash | Rock Bottoms | Don't Be Blue

Acid Rain

Students create "acid rain" in a glass dish by reacting two chemicals. The gas created by the reaction combines with a drop of water to form an acidic solution (acid rain).

When does rain hurt trees?

Sodium sulfite reacts with hydrochloric acid to produce sulfur dioxide gas. The sulfur dioxide reacts with the water in the indicator to produce sulfurous acid. Industry produces sulfur dioxide by burning coal, among other ways. This experiment shows how the creation of a gas can cause a raindrop to become acidic. In the air, the gas mixes with rain to produce sulfurous acid, which is harmful to plants and animals.

Burning Issues

Students use a candle to discover the products of combustion. The flame deposits carbon on a glass rod and water on the sides of a jar. Carbon dioxide gas reacts with the water in an indicator to form carbonic acid.

What chemical reaction occurs when a candle burns?

Wax molecules are made of carbon and hydrogen. As wax burns, it reacts with oxygen in the air and produces carbon, carbon dioxide, and water. The flame goes out when the oxygen is depleted. The combustion of a candle is similar to that of wood or gas. Combustion creates pollution. Carbon particles add to smog, and carbon dioxide is a 'greenhouse gas' that may contribute to global warming.

Cleaning with Charcoal

Students pass a copper sulfate solution and a food coloring solution through a charcoal filter. The copper sulfate passes through the filter along with the water, but the food coloring is filtered out, leaving clean water.

What happened to the food coloring in the water?

Charcoal filters work by removing large organic (carbon-containing) molecules. The surface of charcoal is full of tiny holes, like a sponge. The large, organic molecules of food coloring get stuck in the holes while the small water molecules pass through. Copper sulfate particles are small enough to pass through the filter with the water.

Foam Peanuts

Students compare the properties of Styrofoam^TM and biodegradable foam packing peanuts when mixed with water and acetone.

How are biodegradable peanuts like pasta?

Biodegradable foam is created using corn starch, so it dissolves easily in water. Acetone, which is flammable and irritating, softens and flattens the Styrofoam(tm) but does not dissolve it. The deflated Styrofoam will not wash away. Styrofoam is difficult to dispose of, but it can be reused and recycled! (Call 1-800-828-2214 for Styrofoam recycling information.)

Take Out the Trash

Students use a magnet and floatation to separate metal screws, plastic and aluminum from a mixture.

How is trash sorted for recycling?

Recyclers use the different properties of chemicals, like magnetic charge or density, to separate trash. Huge magnets separate out steel items. Density differences separate other trash into "sinkers" and "floaters." Recycling helps protect the environment by reducing the amount of raw materials taken from the earth, and the amount of trash that goes into landfills.

Rock Bottoms

Students add simulated acid rain to two cups that represent lakes. One cup contains limestone gravel, the other contains granite gravel. Students also add an indicator to each solution that shows any change in the acidity of the "lakes."

How can a lake neutralize acid rain?

Limestone is made mostly of calcium carbonate. It reacts with the acid in the rain, producing hydrogen carbonate and a neutral salt, neutralizing the lake. Granite does not react with acid and does not neutralize it.

Don't Be Blue

Students compare two solutions of copper sulfate, which represent 'hard' water. They pass one solution through an ion exchange resin. They add soap to both solutions, shake them, and observe the results in each.

What makes the ring in your bathtub?

Hard water has minerals, mainly calcium ions, dissolved in it. Calcium can prevent soap from sudsing and leave a ring in your tub. Ion exchange resins remove unwanted ions, like calcium, magnesium, and iron from hard water. The resin is made of tiny beads with hydrogen ions on their surfaces. As the hard water passes through them, the hydrogen ions trade places with the mineral ions. The minerals are left behind and the result is soft water.

go back to Inquiry Session 1 | go on to Inquiry Session 3

Inquiry Sessions | Resources | Teaching Guide