This is meant to be handed out to the students.
There are over 100 types of atoms (usually seen in the periodic table). The atoms are hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, etc. The type of atom is determined by the number of protons in the nucleus, since this the chemical properties that the atom will have. Hydrogen, for example, is composed of one proton with one electron hovering over it. Oxygen is composed of 8 protons and 8 neutrons in the nucleus and 8 electrons hovering over it. Chemistry is the study of how atoms bind together. For example, two hydrogens and one oxygen like to bind together to make a water molecule. A molecule is formed when the electrons from one atom interact with another atom, making a bond between them. Sometimes electrons are shared between atoms. Sometimes an electron is transferred from one atom to another, and they are held together because now one atom is positively charged and one is negatively charged; opposite charges are attracted due to electrical fields.
These chemical bonds store energy. If we made hydrogen and burned it, the burning process would make heat. During burning, the hydrogen makes chemical bonds with oxygen atoms in the air to form water. Water is a lower energy state, so some energy is given off. When we burn gasoline in our cars, it produces heat which runs the car motor. When we eat food, we get energy to heat and move our bodies. Batteries convert chemical energy directly into electricity.
In this lab, we produce heat from a chemical reaction, and we will make our own batteries.
[equation missing; we're looking for it.]
Do you see which bonds are breaking and which ones are forming? How many bonds do carbons like to make? ________
How many bonds do oxygens like to make? ________
This is the reaction of an acid and a base to produce a salt plus water.
B. Use the batteries provided to light a diode, a light bulb, and to buzz a buzzer. Use the voltmeter to measure the voltage of one battery.
Now, put the batteries so that the positive and negative surfaces are touching. What is the voltage of the combination?
What happens if you put the positive sides together?
Measure the maximum current from the batteries (THIS SHORTS IT OUT, SO DON'T KEEP THIS CIRCUIT CONNECTED VERY LONG!!!!!)
Maximum Current: ________________
C. Make your own batteries. To make a battery, you need two metals and a solution of ions. In our case, we will use acids of various types. Fill a beaker 2/3 full with lemon juice. Attach a buzzer to a copper rod on one side and a zinc rod on the other side. Place the rods in the lemon juice. You should hear a buzz. Does it matter how far the rods are in? _______ Does the sound change with time? _______ Does it matter where the rods are in the solution? _______
Measure the Voltage and the maximum current from your battery.
voltage: ___________ Maximum current: ____________
Which direction is the current flowing, from the copper to the zinc or from the zinc to the copper? ___________
Electrons come out of the anode of the battery and are deposited at the cathode.
Now try different metals, different numbers of rods of each metal, and different acids.
# Metal 1 # Metal 2 acid anode V Max. I _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________
2. If the maximum current that your batteries will supply is 0.01 amps, how can you light a light bulb that requires at least 0.015 amps?
3. What is an atom?
4. What is a chemical bond?
5. How do batteries work?
Important Disclaimers and Caveats