Electroplating
EXPERIMENT
Visitors plate zinc onto brass brads and other metal objects.
OBJECTIVES:
Visitors learn how metals that conduct electricity can be coated with
other metals.
SCIENCE TOPICS
PROCESS SKILLS
VOCABULARY
Electricity
Observing
Atom
Properties of Metals
Properties of Ions
Investigating
Inferring
Electron
Electroplating
Atomic Structure
Ion
Metal
Solution
Unit 5 Industrial Chemistry
Experiencing Chemistry ©2007 OMSI
U5.1
Experiment: Electroplating
Operating Guide
Electroplating
Procedure:
1. Always wear safety goggles.
2. Clip a clean brass fastener to the end of the red wire.
3. Hold one wire in each hand at the place
marked with yellow tape.
 Find the plastic tub filled with zinc
sulfate (ZnSO4) solution.
 Place the black wire with zinc metal
into one end of the plastic tub.
 Place the wire with the brass fastener
into the other end of the tub so that the
fastener is about half covered by solution.
DO NOT touch the wires together and
DO NOT put your fingers in the solution.
4. Hold the wires in place for about 45 seconds.
5. Remove the wires from the solution and briefly dip the ends of
both wires into the beaker of rinse water. Look closely at the
brass fastener. Do you notice any change in the fastener?
You have zinc plated the fastener!
6. Put the fastener in the cup labeled “Used Metals.”
Try the experiment again with other metals.
Are your results the same or different?
7. Rinse and put all used metals in the “Used Metals” cup.
Wash your hands in the sink.
©2007 OMSI
How did the zinc get on
the brass fastener?
A Closer Look:
In this experiment, an electrical current from the
battery flows through the fastener and the solution.
Zinc ions (positively charged zinc atoms) in the
solution are attracted to the fastener at the negative
terminal of the battery. When the zinc ions hit the
fastener, they are supplied with electrons from the
battery and are turned into a solid zinc coating. This
process is called electroplating.
Electroplating is used in industry to coat one metal
(e.g., iron, zinc, steel) with another metal (e.g., zinc,
copper, silver). Only an electrically conducting metal
can be plated in this way. Electroplating is often done
to protect a metal from rust; for example, zinc is used to
protect iron. Electroplating also is used to enhance the
appearance of metal objects; for example, some jewelry
is coated with gold.
©2007 OMSI
Experiment: Electroplating
See Materials Prep
for more details
Operating Guide
(with amounts to have on hand)

Three plastic cups

One rectangular plastic tub approximately 5 in. long, 4 in. wide, and 2
in. high

One piece of aluminum foil (large enough to cover the tub)

One 250-ml beaker

One 6-volt lantern battery (keep two fresh batteries on hand)

Two heavy-duty alligator clips attached to both ends of a red insulated
wire about 1 ft (30 cm) long (keep spare on hand)

One alligator clip attached to one end of a black insulated wire about
1 ft (30 cm) long (keep spare on hand)

About 150 g of ZnSO4 (zinc sulfate) (keep 500 g on hand)

CuSO4  5H2O (copper sulfate) (optional) (keep 500 g on hand)

50 brass paper fasteners (keep 500 + on hand)

50 assorted metals (screws, paper clips, nails, keys, pennies, etc.)
(keep 200 + on hand)

Zn (zinc) metal strip (2 in. by ⅜ in.) (keep a few spare pieces on
hand)

Wire strippers (from general storage)

One voltmeter (from general storage )

Electrician‟s tape

One or two 500-ml storage bottles
Setup/Takedown Procedures
 Label the rectangular container “Zinc Sulfate (ZnSO4) Solution.”
 Label the beaker “Rinse Water.”
 Label the three plastic cups “Brass Fasteners,” “Used Metals,” and
“Other Metals.”
 Cut Zn (zinc) metal strips (2 in. by ⅜ in.).
 Strip 1 in. of one end of the red wire (the end without the alligator clip).
Wrap the wire through the hole of the zinc strip. Secure the metal
strip with electrician‟s tape.
 Attach one clip of the black wire to the negative terminal of the battery.
Attach one clip of the red wire to the positive terminal of the battery.
Use electrician‟s tape to secure both wires to the battery terminals
and to cover all exposed metal. Make “handles” with electrician‟s tape
about 3 in. from the loose end of each wire.
U1.24
Unit 5 Industrial Chemistry
Experiencing Chemistry ©2007 OMSI
Experiment: Electroplating
Operating Guide
 Make sure the labeled container, cups, Zn (zinc) strips, assorted
metals, brass paper fasteners, battery, and wires are in good working
order (see Original Setup).
 Prepare ZnSO4 (zinc sulfate) solution as needed (see Materials
Prep).
 Place the lab voltmeter in the experiment tub.
 Set out the visitor instructions in a Plexiglas holder.
 Set out the following on a tray:

Labeled rectangular tub

Three labeled plastic cups

Labeled beaker

Battery with attached wires
 Pour about 50 ml of ZnSO4 (zinc sulfate) solution into the rectangular
container. (The solution should cover the bottom to a depth of at least
¼ in.).
 Put the brass fasteners and other metals in the appropriate cups. Fill
the beaker with fresh water.
 Replace the brass fasteners after a few uses.
 Replace the assorted metals as they corrode.
 Using a voltmeter, check the voltage on the battery-it should be close
to 6 volts.
 Try the experiment. If you do not see significant plating in 45
seconds, pour the ZnSO4 (zinc sulfate) solution down the drain with
plenty of water. Refill the rectangular container with about 50 ml of
fresh solution.
 Rinse the water beaker.
 Cover the ZnSO4 (zinc sulfate) container with aluminum foil.
 Recycle the used metal by soaking it in vinegar overnight or by
soaking it in 1M HCl for 1 to 2 minutes. Replace the metal pieces
when they begin to corrode.
 Return the equipment to the tub.
 Store the tub and instructions under the counter.
 Discard the ZnSO4 (zinc sulfate) solution in the tub by rinsing it down
the drain with plenty of water.
 Return the voltmeter to general storage.
Unit 5 Industrial Chemistry
Experiencing Chemistry ©2007 OMSI
U1.25
Experiment: Electroplating
Operating Guide
 Clean the tray and leave it at the station.
 Clean all equipment and return it to the tub.
◊
Visitors can try plating their own objects (keys, coins, etc.). Make sure
they rinse the metals well before taking them home.
◊
Check the setup periodically to ensure that the wires are out of the
solution and are not touching each other (otherwise the battery will
run down quickly).
◊
You can use the waste HCl from rocket science to clean Zn off keys to
reuse. To do this, place keys in a beaker with waste HCl just barely
covering them overnight. When keys turn reddish, recycle them (they
are no longer reusable).
Visitors can „reverse plate‟ the piece of metal by attaching the black
wire (with zinc metal) to the negative terminal and the red wire (with
the object) to the positive terminal.
Ask visitors what they would need to copper-plate something. They
can even try it if you provide them with 1.0M CuSO4 (copper sulfate)
solution.
ZnSO4 (zinc sulfate) and CuSO4 (copper sulfate) are hazardous
substances; follow handling and disposal instructions.
Consult the Material Safety Data Sheets (MSDS) for additional
information.
U1.26
Unit 5 Industrial Chemistry
Experiencing Chemistry ©2007 OMSI
Experiment: Electroplating
Operating Guide
To prepare 1.0M ZnSO4 (zinc sulfate) solution:
 Wearing a lab coat, protective eyewear, and gloves, weigh 143.8 g
ZnSO4  7H2O (or 89.8 g ZnSO4  1H2O)
 Add to 500 ml H2O
 Store the solution in a labeled/dated plastic bottle.
To prepare (for “Extensions” only) 1.0M CuSO4 (copper sulfate) solution:
 Wearing a lab coat, protective eyewear, and gloves, weigh 125 g
CuSO4  5H2O.
 Put the CuSO4  5H2O into a beaker of 500 ml dH2O (deionized
water).
 Mix the solution.
 Store the solution in a labeled/dated plastic bottle.
Unit 5 Industrial Chemistry
Experiencing Chemistry ©2007 OMSI
U1.27