Lead (Pb)

Student Objectives: Students will learn the basic properties of lead and why it is both useful and dangerous.

Tips for the Teachers:

Suggested Activities:

1. Bring in lead items such as fishing weights and jigs, or weights from tires used for balancing wheels. Use bulk lead to demonstrate how easily lead can be bent and shaped.
2. Discuss why the laws are changing to require hunters to use stainless steel shot or bismuth shoot instead of lead shoot. (Waterfowl poisoning and lead content in agricultural soil.)
3. Do an experiment for density. Bring in pieces of woven cloth ranging from cheesecloth (open weave) to canvas or twill (tight weave). Experiment with them to see which ones are heavier, which allows the most light through (shine a flashlight or hold up to a window) and how easily water runs through a piece held horizontally. Explain that the molecules of lead are more dense (closer together) than those of other metals.
4. Discuss the meaning of common phases or terms as “leadfoot”, “get the lead out,” “lead overshoes” and “going over like a lead balloon.” Have each student illustrate one of the expressions.

Measurements/Evaluation:

1. Why aren’t water pipes made of lead?
2. Why would a dentist put a lead apron on a person who was having their teeth    x-rayed?
3. Why is lead good for fishing weights?
4. Pencil lead used to be made out of lead. Now what is it made out of?

Lead

Color: Bluish-gray

Weight: A little more than 11 times the weight of water

Found: With other minerals in ores. Main mineral that contains lead is Galena, a lead sulfide.

Lead is a heavy, easily melted and rust proof element. It is also soft enough to leave a streak when it is rubbed on an object. Pencils used to be made of lead. Now they are made of graphite, which is a form of the element carbon.

Lead is also very dense. That means its molecules (very tiny parts) are close together. If you were to lay a sweater and a canvas bag on your desk, you could see the desk through the sweater, but not the canvas bag. That is because there are big spaces between the threads in the sweater, and the threads in the canvas are close together with almost no spaces between. The molecules in lead are like that. Lead is used to line aprons for people who work around x-rays and nuclear radiation. There are not enough spaces in the lead for the radiation to get through. That is also why it is used for containers in nuclear power plants.

Even though lead can be used to protect the outside of the body, it is dangerous to the inside. If lead gets into the body it collects there and cause poisoning.

The United States uses a lot of lead. The single most use of lead is in electric storage batteries for power to start automobiles, trucks, buses and other vehicles. About 18 pounds of lead is in each car battery. Bullets are made from lead because they are dense, heavy material will go farther and straighter than other materials when shot from a gun. Since it is easily shaped and heavy, lead makes good weights for fishing. It is also used for balancing airplane and automobile wheels to make them go around smoothly.

Water pipes used to be made of lead because it is easy to shape and corrodes very little. Since then, people have discovered that lead gets into the water and poisons people. Other metals are now used for pipes instead.

Directions: Do the activities below.

1. Draw a picture of how lead is used today.

2. Draw two things that lead was in but not anymore.

3. Why is it not good to have lead in your body?