Mercury
(Hg)
Student Objectives: Students
will learn the basic properties of mercury and some of its uses.
Tips for the Teachers: Fill a
glass or jar with ice water. Watch the moisture condenses on the glass and roll down. If
possible, start by heating water to make steam and catch some inside a glass. Discuss the
meaning of “vapor.”
Suggested Activities:
- Using a mercury thermometer, record the temperature in the
classroom and out doors each day for a week or month. Record at the same time each day.
Chart or graph the results.
- Have students draw a thermometer showing today’s
temperature.
- Discuss the Greek god Mercury and mythology. Talk about why a
car or horse might be named Mercury.
- Discuss “expand” and “contract.” Illustrate
them with a balloon.
Measurements/Evaluation:
- What do fluorescent lights and many streetlights have inside
them?
- What is dangerous about mercury?
- Mercury is the only metal that is what at room temperature?
- What is the silver material inside a thermometer? What does it
do in heat and cold?
Mercury
Color: Silver white, shiny
Weight: More than 13.5 times
the weight of water, heavier than iron
Found: In a red mineral called
cinnabar, a mercury sulfide
Mercury is the only metal that is
liquid at room temperature. Because of this and its bright shiny appearance, it was
nicknamed quicksilver. Many minerals are good for your body in small amounts, but mercury
is poisonous. It may seem strange to know that mercury is used in dental alloys (called
amalgams), but the other minerals in the amalgams keep it from hurting you.
Mercury combines well with other
things and conducts electricity well. All metals expand in heat and contract in cold. You
can see this property in action when you use a glass thermometer. The silver material that
shows the temperature is mercury. Barometers and electric switches also use mercury.
An important use of mercury is in the
form of mercury vapor (tiny bits of mercury floating in the air). When the ore
called cinnabar is heated, it separates into mercury vapor and sulfur. The mercury is
collected by allowing it to condense on cold glass tubes and roll down, in the same way
that water vapor collects on the outside of a glass of pop.
Mercury vapor is put inside glass
containers for lights. The container is filed somewhat like a helium balloon. When an
electrical current goes through the vapor, it gives off a bluish-white light. You can see
lights like these in street lamps, sun lamps and fluorescent “tubes.”
Directions: Find five words
that go best with each picture. Write the words on the pictures.
