week 6: light it up!

This week's 52 Weeks of GUST project is quite practical -- it's great for holidays and special occasions. Next time, instead of going out to the store to buy a greeting card, make these super special LED greeting cards to light up a room!

Materials: 

• Card stock paper
  
• Copper conductive tape
  
• LED (2 pin, 5 mm)
  
• 3V battery
  
• Regular (Scotch) tape
  
• Assorted pens/markers, for decorating your card!
  

Directions:

1. Fold the card stock in half, such that you now have a blank greeting card.
   
2. Draw a design on the front. Decide where you'd like to place the LED on the card. For example, you could draw a cake and have the LED go on the flame of a candle.
   
3. Make a small hole through the point where you'd like the LED to go through. 
   
4. Open the card up, and on the back of the design, plan out your copper tape path. You will have to create a path of tape from one pin of the LED to the other. One end will go straight down the page, and the other end will be in contact with the battery. The negative (shorter) end of the LED will go towards the battery, and the positive (longer) end of the LED will go towards the corner of the page. Look at the reference images for guidance.
   
5. Tape back the LED pins onto the copper tape.
   
6. Fold in the corner of the card, as seen in the images. To turn on the light, fold the corner so that it touches the battery. To turn it off, simply unfold the corner.
   

What's Going On?
You've just created a circuit! A circuit is simply a path through electrical current flows. In order for a circuit to work, the path must be complete. That means that there cannot be any holes or gaps throughout the path. In this case, the copper tape makes up much of the path. When the folded corner of the card with one end of the tape touches the battery, the circuit is closed and the light can successfully turn on. However, if this path is broken, such as when the corner is unfolded, the circuit is no longer complete and the light turns off!