Discovery Express
  • Welcome!
  • Blog
  • Check out our store!
  • 9 Apples Math Game
  • Your questions answered!
  • About/Contact

Saltwater buzzer: Test the current!

8/9/2015

0 Comments

 
Author: Maddie Van Beek

Most of you probably know that electricity is able to travel through some materials, but doesn’t travel through others. For example, electricity can easily travel through metal such as copper, but it does not travel well through plastic. If electricity can easily be transmitted through a certain material, that material has good conductivity. Another word for conduct is transmit or transfer. If electricity cannot travel well through a material, that material has poor conductivity. 




Example: Wood has poor conductivity. Most metals have good conductivity. 

Picture
http://www.online-sciences.com/wp-content/uploads/2015/03/conductors-2.png


Check out the link below to learn more about conductivity: 

Conductivity
Look at the photos below. Which items are conductive? Which are not? 

Picture
http://cdn.omg-facts.com/2012/6/8/dddbcc1f839f0246c9167667026f7c2f
Picture
http://obidotoys.com/images/westcott_shatterproof_12_ruler.jpg
Picture
https://www.fantasyjewelrybox.com/Images/ProductFull/19775-4727/unisex-plain-sterling-silver-wedding-band-ring-6mm.jpg
Picture
http://shard4.1stdibs.us.com/archivesE/jewelry/1stdibs/071913/WimpoleJWL_LON_LB_CC//09/x.jpg
Picture
http://www.meiselrockproducts.com/wp-content/uploads/2014/07/rocks-323419_640.jpg
Picture
http://images.fineartamerica.com/images-medium-large-5/crushed-plastic-bottle-daniel-sanchez-blasco.jpg
Today, you are going to be using electricity to test water for its saltiness. What?! How could electricity tell you whether water is salty or not? Well, when salt is dissolved in water, the salt atoms break apart and become ions, which contain a positive or negative charge. Atoms become ions when they gain or lose electrons. Remember, electrons are negatively charged, so if an atom gains an electron, that atom becomes a negative ion. If an atom loses an electron, that atom becomes a positive ion. 

Remember when we learned about atoms and ions when we bent a stream of water with static electricity?

Believe it or not, salt water will conduct electricity! Lets try it out. 




YOU WILL NEED:

  • Glass
  • Distilled water (must be distilled, not tap or drinking water)
  • Salt
  • Buzzer (a.k.a piezo transducer/buzzer.  You can find this online at a variety of vendors.  Click here for examples. Be sure to get one with a black and a red wire!)
  • 9-volt battery
  • 2 wooden craft sticks (or Popsicle sticks)
  • Aluminum foil
  • Electrician’s tape



Here’s what to do! 

  1. First, wrap each craft stick with aluminum foil. 
  2. Use the electrician’s tape to attach the red wire of the buzzer to the positive end of the 9-volt battery. The positive end of the battery will have a plus sign on it (+). 
  3. Tape one of the foil-covered craft sticks to the negative end of the battery. The negative end will have a minus sign on it (-). 
  4. Tape the second foil-covered stick to the black wire of the buzzer. 
  5. Now, test out your circuit. Touch the tips of the two foil-covered craft sticks together. BUZZ!!! When the circuit is complete, your buzzer should have gone off. If the buzzer did not sound, go back and check your connections to make sure everything is in place. If this does not work, try a new buzzer. 
  6. Fill a glass with one cup of water. 
  7. Place both ends of the foil sticks in the cup of water so they are about one inch apart. Does anything happen? Record results. Is plain water conductive or not? How do you know?
  8. Remove the foil sticks from the glass. Mix one tablespoon of salt into the glass of water. Stir in the salt until it fully dissolves. 
  9. Once again, place the ends of both foil sticks into the glass of water so they are about one inch apart. What happens? Record your results. Did salt water conduct electricity? How could you tell? 



Follow-up Questions:

1. Did the buzzer sound in plain water? Why or why not? 

2. Did your results change when you added salt to the water? Why would salt make a difference? 


3. How is saltwater able to conduct electricity? 



Extensions: Try using sugar water instead of salt water. Do you get the same results? What if you try using Gatorade or milk? Will other liquids conduct electricity? Try it out! 




References

http://www.education.com/activity/article/Experiment_with_Salt_Water/

http://pbskids.org/zoom/activities/sci/saltwatertester.html

https://en.wikipedia.org/wiki/Ion

http://www.physics4kids.com/files/elec_conduct.html

0 Comments

Your comment will be posted after it is approved.


Leave a Reply.

    Follow us on Pinterest!
    Picture
    Check out our new game for math education, grades 1-7!

    Archives

    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    February 2015
    January 2015
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014

    Categories

    All
    Age 10 12
    Age 12 14
    Age 14 16
    Age 16+
    Age 8 10
    Anatomy/Physiology
    Biology
    Chemistry
    Engineering
    Food Science
    Geology/Earth Science
    Health Science
    Math
    Microbiology
    Physics
    Plant Science
    Psychology
    Weather Science

Proudly powered by Weebly