Silica (SiO2)

Student Objectives: Students will learn where silica is found and what its oldest uses are. They will also learn how we get silicon and what are some of its uses in both pure form and compounds.

Tips for the Teachers: Demonstrate the difference between traditional and non-stick cookware in class by frying and egg in each. Discuss the health values of using less or no oil.

 Suggested Activities:

1. Ask a local computer store or school to visit the classroom and discuss computer chips and the many other parts of the computer that are made of silica.

2. Prepare samples prior to class of items protected by silicone caulk or wax products. Heavy paper or cloth are good choices. In class, demonstrate the protection by spraying prepared and unprepared items with water and/or dipping them in water. Ask class to observe and comment on the results.

3. Have students make a list at home of at least 3 items or products containing silicone found in their home. Students should bring the lists to class and discuss them.

4. Arrange at least six glass containers of the same size on a table. Fill each with a different amount of water. Tap the side of each glass with a table knife or other metal object and listen to the different tones produced. Reinforce the fact that silica is used in glassmaking.

Measurements/Evaluation:

1. Where is silica found?
2. What is the oldest use of silica?
3. Silica products have been mad for over how many years?
4. How do we get pure silicon?
5. Why is silicon important to the computer industry?
6. List two things that can be protected from water with silicone compounds.

 

Silica

Silica is found all over the world in ordinary rock of all kinds, except limestone. Silica is a compound of the elements silicon and oxygen, and often contains other elements. Some kinds of silica have been used for making glass and pottery for more than 13,000 years. Silica is still used for these things today. It is also the most common material that comes from sand and gravel products.

Silica can be heated and separated to get pure silicon, which can be added to alloys and compounds. Silicon is used to make transistors for radios and calculators, solar cells to collect energy from the sun, and electrical parts. These are very important to the computer industry. There is an area in California where many companies make electronic parts. Silicon is so important to their business that it is known as the Silicon Valley.

Avery important group of products that contain silicon is the silicones. These are man-made materials that have silicon and other elements in them. Plastics, rubbers and grease-like liquids can all be made of silicone compounds. The rubber products can be molded into many shapes and are important in machine parts and medicine. Doctors can make new parts for the body like heat valves or arteries to replace damaged ones. The body will accept these new parts better than any other man-made things they have tried.

Silicones are used to make non-stick cooking pans. The coating lets foods be cooked without using oil. Liquid silicones are used like grease to keep surfaces sliding smoothly, without rubbing or scraping.

The Largest number of different uses for silicone products is in waterproofing. Almost everything, including shoes, clothing, buildings and even radio equipment can be protected from water with silicones. Another place you might see silicone is in the caulking around your bathtub or shower.

As you can see, silica products are very important to us. Since silica is almost everywhere around us, we will not have trouble finding enough to use for a long time.

Directions: Count the objects that have silicone parts and write the number in the space provided.