Charged Up! Activity Worksheet
Station 1: What is Electric Charge?
Atoms are made of a nucleus (positively charged protons and uncharged neutrons) surrounded by
electrons with a negative charge. Protons and electrons have equal but opposite charges, so if an atom has
equal numbers of each it will be electrically neutral. However, if there are an unequal number of protons
and electrons, then there will be either a positive or negative charge (also called an ion).
Neutral: equal numbers of protons and electrons
Positively charged (+): more protons than electrons
Negatively charged (-): more electrons than protons
Electrons can move around to different atoms, especially when energy is added, so objects (which are
made up of atoms!) can and do lose and gain electrons every day!
An important characteristic of electrical charges is that opposite charges exert forces that attract each
other and like charges exert forces that repel each other. So if one object is positively charged and
another is negatively charged, then they will come together and if both are positively or negatively
charged, they will go in opposite directions. A charged object (whether + or -) will have an attractive
interaction with a neutral object.
Questions:
1) If an object is made of atoms that have 7 protons and 6 electrons be attracted or repelled to
a 2nd object made of atoms with 5 protons and 3 electrons?
2) If an object is rubbed against a material that causes it to gain electrons, will it be attracted or
repelled to a neutral object?
Station 2: “Sticky” balloons
Take a small amount of torn up paper and lay it on the desk. Now take a yellow balloon, roll it
around in the water and pat dry with the paper towel. Now press it against the paper on the desk.
Describe what happened:
Now take a pink balloon and rub it against your head. After a few rubs, press the balloon against
the paper.
Describe what happened:
Pick up a yellow balloon again, roll in the water and dry, and then press it gently against the
white board (or wall) in front of the room. Then let go.
Describe what happened:
Now take a pink balloon, rub it against your head a few more time and then press it gently
against the white board (or wall).
Describe what happened:
Why do you think there was a difference in the “stickiness” of the balloons?
After you rubbed the balloon against your head, was the force attractive or repulsive
between the paper and the white board? What possible charges could the balloon and these
objects have?
When you rubbed the balloon against your head, electrons were transferred from the
atoms in your hair to the atoms in the balloon. When this is done, what charge is given to
the balloon? Your hair?
Station 3: Conductors and Insulators
Conductors are materials that easily allow the movement of electrons from some atoms to
others. In this way and electrical current can pass one place to another (just like how it travels
through a wire from an outlet to a TV!) Insulators are materials that do not easily allow
electrons from travel from some atoms to others so electric currents cannot travel through them
very well. Notice all of the different objects on the table. You will be exploring which ones are
conductor and which ones are insulators by testing which ones will complete a circuit and light
up a light bulb! The battery in the circuit provides the source of electrons at the negative end,
which must pass through the circuit (including the light bulb) in order to reach the positive end.
The lighting of the bulb indicates that the electrons are moving.
Before you start, which objects do you think will light up the light bulb?
Now with you group members, test your predictions and record your findings below:
The bulb lit up when I used:
The bulb did not light up when I used:
What kinds of material were conductors made of?
What kinds of material were insulators made of?
Do you think you (humans) are a good conductor or insulator?
Hint: think of what happens when a human gets struck by lightning!!
Station 4: Magnets
Take the magnets on your table and write down what happens when you put the following poles
together”
Positive to positive:
Negative to negative:
Positive to negative:
How are magnetic forces similar to electrical charge?
Now a compass and move it to the N and S poles of a magnet.
Draw an arrow the picture where the compass needle points at the S and N ends of the
magnet:
Station 5: Magnetic Earth
At this station you are going to see what happens to a magnet when it is free to move without any
other magnets close by. Take a needle and rub is gently against the magnet on the table. This
makes electrons in the needle act like magnets too. Carefully place a square piece of tissue paper
on the surface of the water in the bowl (don’t make it sink!). Now carefully place the needle on
top of the tissue paper to allow it to move on its own.
Note down what parts of the classroom each end of the needle points to:
End #1:
End #2:
What directions do you think each end of the needle point in?
Will the N (north) or S (south) end of a magnet be attracted to the North Pole on Earth?
Is the Earth a magnet?
References:
The Physics Classroom Tutorial:
http://www.glenbrook.k12.il.us/gbssci/Phys/Class/estatics/u8l1b.html
Introduction to Magnets- Sheila McKinnon
http://www.iit.edu/~smile/ph9515.html
Attracting Balloons- An Educator's Reference Desk Lesson Plan, Lesson Plan #:AELPPHS0003http://www.eduref.org/Virtual/Lessons/Science/Physics/PHS0003.html
Insulators and Conductors- http://www.ewh.ieee.org/r3/cnc/tisp/cd/tisp-ov/PDF-LESSONPLANS/8_English_InsulatorsandConductors.pdf
Conductors and Insulators, Consumers Energyhttp://www.consumersenergy.com/uploadedFiles/Kids/Conductors%20and%20Insulators.pdf
Electromagnet Image
http://images1.wikia.nocookie.net/schools/images/5/5e/Motor-nail-in-horseshoe.jpg