Praxis: Conductive dough
By Medicine Hat News on November 18, 2017.
It has been a busy few weeks with requests for electricity. With a turn in the weather, what better thing to investigate! If the truth was told, I am not an expert by any means in this field. I have had to do my homework, some research and brush up on my skills in this area, and wow did I find some pretty interesting hands-on science experiments to share. Let’s get started! *Remember to ask an adult before you do this experiment. Materials – measuring cups – measuring spoons – mixing bowl – missing spoon – flour – cream of tartar (found in the spice section at the grocery store) – food colouring (optional) – LED lights – 9V battery – wires with alligator clips – vegetable oil – salt – sugar – stove top or hot plate – pot to cook the mixture in – sink (to clean up) – plastic containers or zipper bags (to store dough in) Procedure 1. Into the pot, mix the following: One cup (250 mL) of flour, one cup (250 mL) of water, 1/4 cup (60mL) of salt, three tablespoons (45 mL) of cream of tartar and one tablespoon (15mL) of vegetable oil. You can also add some food colouring at this point. I would advise colouring one of the dough mixtures so you can tell them apart. Stir well and place over medium heat. 2. Allow this mixture to cook until the dough pulls away from the sides of the pot. 3. Remove the dough from the heat and allow it to cool until you can handle it. 4. At this point you may have to knead a bit more flour into the dough so it can be molded into various balls or shapes. This is your conductive dough. 5. Place the dough in a sealable container until you are ready to use it and then it will not dry out. 6. You need to make the insulating dough. 7. In a clean pot, mix the following: one cup (250 mL) of flour, 1/2 cup (125 mL) of sugar), three tablespoons (45 mL) of vegetable oil and 1/2 cup (125 mL) of water. 8. Repeat steps 2 -5. 9. Build your circuit now! 10. Take one piece of conductive dough and roll it into a nice ball. Repeat so you have two balls of conductive dough. 11. Repeat, making one ball of insulating dough. 12. Place the dough balls together with the insulating dough in the middle. 13. Take the LED light and gently separate the prongs on the bottom. Place one prong in one ball of conductive dough and the other prong into the other ball of conductive dough. You are doing this to ensure the electricity will flow into the LED light. 14. Take the alligator clips and attach one to each post of the 9V battery. 15. Place a penny on one end of one alligator clip and a paper clip into the other alligator clip. 16. Gently insert the penny into one of the conducting balls and the paper clip into the other conduction dough ball. 17. Watch what happens. What is going on? In this experiment you made conductive dough first and insulating dough in the second part of the experiment. When I first tried this, I thought it was pretty amazing myself — but that is likely the inner science geek talking! It is amazing though if you really think about it. What looks like plain old dough can transfer electricity. How does this happen? In the conductive dough the salt and water allow electricity to flow and light up the bulb. Conductors allow the electricity to pass through them. On the other hand, insulators do not allow electricity to easily pass through them. Resistance is a measurement of how insulating something is. This dough is resistive which means little electricity can flow through it. Once you have mastered creating these simple circuits try to make parallel and series circuits. You can also try to make buzzers work, or fans move. Check out what they may have at the electronics store as the possibilities are endless! Patty Rooks is senior scientific consultant at PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. 45-44
