Jolie Rouge

http://invention.smithsonian.org/cen...ghtbulb_01.asp



MAKE A LIGHT BULB

Materials you will need to make a bulb

• One small jar
• Cork stopper for a lid
• A 1-inch nail
• Three feet of shielded copper wire
• One 6-volt battery--not a car battery!
• Thin iron wire (the best source for this is unraveled picture hanging wire)

Materials you will need to record your results

• A copy of the "Record my results" form
• A watch with a seconds hand
• A pencil



IMPORTANT SAFETY HINTS:
(1) This experiment needs to be done with an adult present and supervising it! (2) Always wear safety glasses and gloves when doing experiments! (3) Be careful handling the filaments when they burn out--they will be HOT! (4) Never play with wall sockets or household electric currents.


Procedure

1. Print your "Record my results" form. You will need it to record the results of your experiment.

2. First cut the copper wire into two lengths about 1-1/2 feet long. Cut off an inch of the shielding (plastic coating) at each end of the strands.

3. With a nail, drill two holes into the cork. Push the wire through the holes in the cork so that about two inches of the wire can be seen in the jar.

4. Make a hook at the end of the copper wires so that you can twist small strands of iron wire around them to make a filament.

5. Twist several strands of iron wire together and stretch them across the gap between the two copper hooks to form the filament.

6. Put cork stopper with filament inside the jar.

7. Carefully hook up both copper wire ends to the battery and watch your bulb light up!

Be careful the filament becomes very hot. Do not touch.



8. Use the watch to time how long your filament glows. Keep a record of how long your filament lasts on the "Record my results" form.

9. Try the experiment again with a different number of iron wire strands twisted together. Record your results.

__________________
Laissez les bon temps rouler! Going to church doesn't make you a Christian any more than standing in a garage makes you a car.** a 4 day work week & sex slaves ~ I say Tyt for PRESIDENT! Not to be taken internally, literally or seriously ....Suki ebaynni IS THAT BETTER ?

Jolie Rouge

How long does it take to recharge a battery?

http://invention.smithsonian.org/cen.../recharge.html


Supplies:
2 Flexible solar shingles
1 12-Volt sealed rechargeable battery
multimeter
test leads


How to take measurements:
1. To measure voltage, turn the knob on the multimeter to 25 DCV, which means the multimeter can measure 0 to 25 DC volts. Touch test probes to the circuit. (This means touch the test probes to the wires of what you are measuring, like the shingle wires or the battery terminals). One probe should touch each wire or terminal. Read and record the voltage.

2. To measure the resistance on the circuit, turn the knob on the multimeter to RX1 Ohms. Touch the test probes to the circuit. Read and record the resistance.

3. Calculate current with Ohm's law.



How long does it take to recharge the battery?

1. First check to see if the battery needs to be charged by measuring the voltage. If a 12 volt battery is fully charged, the multimeter should read 12 volts. If your battery is already charged, try the How long will a battery hold a charge? activity first. If your battery has less than 12 volts, you can charge ahead!

2. Position the solar shingles in a sunny location. Measure the voltage and resistance of one shingle. Calculate the current.

3. Connect the two solar shingles in series. Measure the voltage and resistance and calculate the current. Did the voltage or current increase? What if the shingles are connected in parallel?



4. Electrical current flows from a higher voltage to a lower voltage. To charge a 12 volt battery, the shingles connected together need to produce more than 12 volts so the current flows into the battery. If the voltage is lower than 12 volts, current flows out of the battery. Using what you learned in step 2, should the shingles be connected in series or parallel to charge the battery?



5. If you guessed series, you are right! If the shingles are connected in series, the voltage is higher than 12 volts so the current will flow into the battery. Now, connect the shingles in series to the battery to start charging!

6. To see how the charging is going, disconnect the battery once every hour, measure the voltage and resistance of the battery and calculate the current. Don't forget to reconnect the battery to the solar shingles each time after measuring the voltage. When the sun goes down, what happens to the voltage and current the solar shingle produces?

Why should you disconnect the battery from the solar shingles when the sun isn't out? (Hint: Think about the direction the current will flow)

Can you think of a way to make sure the current only flows into the battery? (Hint: Check out the How does a photovoltaic panel work? activity and read about diodes)

How long did it take to recharge the battery?

__________________
Laissez les bon temps rouler! Going to church doesn't make you a Christian any more than standing in a garage makes you a car.** a 4 day work week & sex slaves ~ I say Tyt for PRESIDENT! Not to be taken internally, literally or seriously ....Suki ebaynni IS THAT BETTER ?