STEAM Subject(s): Physics (Electricity & Circuits),
Basic AA wired battery box
Two AA batteries
2 paper clips
3 or 4 jars
Construction paper or cardstock
Elmer’s White School Glue
Coloured LED light
Using electrical tape, attach the wires on the battery pack to the
paper clips. Set to the side.
Put 3 or 4 spoonfuls of salt into each Ball jar. Add 2 or 3 drops of
food colouring. Close the lid and shake.
Cut the paper in half.
Using the glue, draw a thick squiggly line on the paper. Since you’re
making a circuit, it’s super important that the glue goes all the way
to the edge of both the top and bottom of both pieces of paper.
Otherwise your light won’t turn on at the end!
Before the glue dries, sprinkle your coloured salt onto the glue. Shake
off the excess salt into a bowl.
Learn More – STEAM Extensions:
What exactly is electricity? Electricity is a form of
energy that we use every day. Take a few minutes to think about how
many times you’ve used electric energy in the last hour. We’re
guessing that it’s a high number! Electric energy gives us light,
charges our phones and computers, and allows our appliances to work.
What is a circuit? Electric energy needs a path to
get from where it is being stored (usually a battery) to where it
needs to work its magic. This path is called a circuit. This circuit
must be a continuous, unbroken loop, or the electricity won’t be able
to travel from the power source to the item you hope to light up.
Did you know that electricity flows easily through some items and
not so easily through others? A conductor is a material that transmits electricity, which means
electricity flows easily through it. In this experiment, the salt, the
metals in the wires, and the paper clips are the conductors. Notice
that the entire circuit is made of conductors. If you took away the
paper clips, wires, or salt, your light bulb wouldn’t light. An
insulator is the opposite of a conductor. Insulators stop the flow of
electricity. Do you see how the wires are wrapped in plastic? That
plastic insulates the wires to contain the flow of electricity.
What about the glue? You’ll notice that the glue is
neither a conductor nor an insulator. Instead, the glue’s job is to
keep the salt together. Had you just clumped a lot of salt on the
page, you might have been able to make a complete circuit, but one
swish of the fingers and that circuit would have been broken. The glue
makes a nice, clear, and complete path for the salt to stick to so
that it can conduct electricity to the light bulb.
Your science project as art. Did you wonder why we
had you colour the salts before using them? The answer doesn’t have
anything to do with science—white salt would have worked just as well
as coloured salt. The answer has to do with art! Lights are beautiful,
and when they glow over coloured crystals (salt), the reflections
twinkle and sparkle. Once the glue on your circuit dries, the paper
clips and light should be permanently attached to the paper. Hang your
art up in your room or place it in a shadow box (where you have easy
access to that battery box switch) and enjoy the colours and the light.
Have you ever wondered how a light bulb lights up? In
the glue salt circuit, you made a path out of salt and glue for
chemical energy to travel. Go you! When given a path made of
electrical conductors (that’s your wires, glue, and salt), the energy
that is stored in the battery starts to move. As long as the path is
free of any obstacles (like a pesky piece of insulating plastic or
some air), the electricity will move right down that path and enter
the light bulb, and the light bulb will light up. What would happen if
you put an obstacle in the way of that traveling electricity? Try
removing one of the paper clips from the glue and salt. Then put air
(an insulator) in between the metal and the salt and the glue
(conductors). Did your light turn off? Yep! Now reattach the paper
clip, and the light should turn on.
Help! My light bulb will not light up.
Make sure the paper clips from the battery pack and the wires from the
LED light bulb are touching the glue lines to form the loop for the
electrical current to flow.
I checked my paper clips and wires, and my light bulb still will
not light up.
Check the battery! If the battery is dead, then the circuit will not
Level Up – Options for Older Kids:
Can you light up two light bulbs? A chain of lights?
Experiment with making a glue salt circuit with more than one light.
You will still only need one power source (battery box), but you will
need to make a continuous loop of conductors with no gaps for the
lights to work. Try using three or four pieces of paper, making longer
glue and salt paths, or adding more paper clips and wire. The
possibilities are endless!
Next Generation Science Standards
4-PS3-2: Make observations to provide evidence that energy can be
transferred from place to place by sound, light, heat, and electric
HS-PS2-5: Plan and conduct an investigation to provide evidence that
an electric current can produce a magnetic field and that a changing
magnetic field can produce an electric current.
HS-PS3-3: Design, build, and refine a device that works within given
constraints to convert one form of energy into another form of energy.