Thursday, January 26, 2012

Valentine Day Science Fun

The vocabulary for these experiments is Carbon Dioxide.
Pumping Heart Model
Have your child breathe in and explain that their lungs are being filled with Oxygen that our bodies use.  Our blood picks up the oxygen from our lungs.  Our blood carries the oxygen all through our bodies and picks up the CO2 that we won't use.  Then it's released from our blood into our lungs for us to breathe out.

Our heart is a huge muscle in our bodies that pumps our blood all through our bodies.  This model shows how the heart muscle can pump blood.

You can make this model of a heart with your child to demonstrate how blood is pumped around the body.  This model only demonstrates how one chamber of the heart would work.

1) Cut the neck off of a balloon.  Place the mouth hole of the balloon over the tip of a straw and tape it in place.   This will act like a valve that closes off after the water spurts from it.  The straw without the valve is needed to allow air into the jar.

2) Fill a mason jar half full of water (you can add a few drops of red food coloring to make the water appear like blood).  Place the body of the balloon over the mouth of the mason jar. 

3)Poke two holes in the top of the balloon with a bamboo skewer.  Push a straw through each hole, making sure there is a closed seal.  The straws need to be submerged in the water.

4) Push on the top of the balloon and observe how the water leaves the chamber of the heart and the valve closes after the water exits.

Why does the "blood" only pump in one direction? (answer: the valves close off and does not allow the blood back into the chamber it just came from.  The little balloon neck taped to the end of the straw loosely demonstrates how a valve works.)

Check out this animated model of how the heart pumps blood:

Dancing Hearts
Good 'ol baking soda and vinegar!   These two substances react to form Carbon Dioxide.  A solid (Baking Soda, or Sodium Bicarbonate) and a liquid (Vinegar, or Acetic Acid) react to form a gas!
CH3COOH + NaHCO3 >> CH3COONa + H2O + CO2

Fill a tall, clear glass half full of water.  Let your child drop in 2 or 3 little candy valentine hearts (conversation hearts).  Observe the hearts.  Now stir in a Tb of Baking Soda (sodium bicarbonate).  Observe the hearts.  Do you see any bubbles forming along the edges?  Pour in a little Vinegar (acetic acid).  Observe the hearts.  Do you see any bubbles forming along the edges? 

Wait for a moment and you will see the bubbles form along the edges of the many bubbles that they buoy up the heart so that it rises to the top of the water.  The hearts will rise and fall.  Why do the hearts fall?  Why do they rise again?

Remind your child that this is the same gas that we breathe out of our bodies and that plants use.
Love Potion
Another round of Baking Soda and Vinegar to create a Carbon Dioxide explosion!   You've probably all done this reaction at home, but put this Valentine's Day twist on it for a lot of chemistry fun!

Pour a Tb of Baking Soda (Love Powder) into a tall, clear glass. We used a vinaigrette cruet because it looked more like a potion bottle.  Drop in 2 drops of red food coloring.  Have your child drop in one or two valentine candies (just for fun- they don't effect the reaction). 

Now pour a tiny bit of vinegar (Valentine's Day juice) into the bottle and swirl it all around quickly.  Watch the liquid turn red and dissolve the solid baking soda. It will bubble slightly.  Now pour a bit more vinegar into the bottle and observe the power of the Love Potion!  Be sure to do this fun little experiment over the sink:)

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