REED COLLEGE SCIENCE OUTREACH PROPERTIES OF MATTER

14
Lesson Three- Exploring Electricity
Objectives
o Students will learn that the flow of electrons is responsible for electricity.
o Students will learn that certain types of matter are better conductors of
electricity than others.
Lesson Background- Electricity
This week, students will review the parts of an atom and learn that the flow of electrons
is responsible for electricity, which powers the electronic devices we use everyday.
They will be introduced to the concepts of electricity, circuits, and voltage by building
batteries with four different types of fruit and using the circuits to power LEDs. They
will also review the scientific method and develop their quantitative skills by recording
the voltages produced by each type of fruit in a table of results. This week, students
should learn that
o An electron is a basic component of every atom that is responsible for creating
current.
o Current is the flow of electrons through a material.
o Voltage is a measure of how strongly electrons are being pushed through a
material (in general, increasing voltage will produce a stronger current, just like
increasing the pressure in a hose will force more water through the hose).
o Resistance is a measure of how tightly a material holds its electrons (if a
material has a higher resistance, then it is harder for current to flow through it,
similar to how a kink in a hose makes it harder for water to flow through it).
o A circuit is a path through which electrons can flow.
Week Two Activity overview
Today, students will build batteries using fruit, use their batteries to power LEDs, and
determine which of four fruits makes the most effective battery.
Materials
o Fruit, roughly equivalent in size:
either lemons, apples, oranges,
or tomatoes
o Copper nails (~1.5” in length)
o Galvanized zinc nails (~1.5” in
length)
o Small red LED with ~2” leads
o 9 alligator clip connectors
o Voltmeter with alligator clip
probes