For every action, there's an equal and opposite reaction. The action is the chemical reaction between the vinegar and baking soda, which yields water and carbon dioxide (CO2) gas. The gas wants to escape, and giving it a little hole to escape, powers the bottle across the water (the reaction).
I did this experiment with the 3rd-5th graders in summer camp many moons ago. It wasn't exactly like this, as I don't remember the details. Luckily, there are plenty of sites out there to refresh my memory. I decided to approach it like I do cooking and looking up recipes online: a little from this recipe and a little from that recipe and add a few ingredients of my own.
Take an old 20oz soda bottle (I used a Diet Pepsi bottle from the power vote days) - the type of drink doesn't matter, though I don't recommend water bottles now that they are more eco-friendly and very squishable (yes, that's an official scientific term).
Dril a hole through the cap (about the size of a straw diameter).
Place about 10 marbles in the bottle to give it weight (since the bottle is buoyant when placed in the water).
Fill up the bottle ~1/4 with vinegar (just plain, cheap, generic name vinegar).
Add ~1T of baking soda to the bottle (other people suggest rolling the baking soda in toilet paper. This was VERY messy and frustrating though just dumping 1T of baking soda in the bottle was relatively painless). -This is a great use for your old baking soda that A&H recommends switching out soon with the time switch. **
Screw on the lid.
Cover the hole in the lid and shake the bottle.
Place the bottle in the water and watch it go!
See if the shape of plastic bottle affects the motion (Mt Dew has a different shape than Diet Coke which has a different shape than Diet Pepsi).
Alter the ratio of baking soda-to-vinegar and see what happens (more/less vinegar and/or baking soda).
Race - you'd probably need a bigger tub than our small cooler.
What made the boat move?
What happened when I put this white powder (baking soda) into this bottle of vinegar (it's also good to ask beforehand too for a hypothesis)?
What would happen if I try this again but differently (your choice on different, or let your child experiment)?
What happens if we remove the marbles from the bottle?
What did the vinegar turn into after the addition of baking soda? (water + CO2 - but the CO2 is what powered your boat)
What else can make your boat move? (J liked using his hands)
**We've also used old baking soda down the drain and added vinegar. It magically unclogged our drain. Not as exciting to a little kid, but it saved us a trip to the store. Woohoo! Science!
J was getting antsy and instead of letting him destroy the house, I decided to build him a quick sail car.
And then he played around with it, even naming it "Lightning McQueen." My only guess for the name was due to how fast it went! Here's a video demonstration. Have your child blow as though they are blowing out candles on a birthday cake.
Main take away from lesson: for every action (blowing on the sail) there's an equal and opposite reaction (the car moves!).
Here's how you can make your own sail car out of recyclables.
Cardboard box (non-corrugated) - I used an empty contact solution box
2 wooden skewers (for kabobs, or in our case, chocolate fountain dipping)
Cut out the bottom of a box (keep it intact so you don't have to assemble a body of the car).
With the remainder of the box, I cut a sail and 4 circular wheels (I used small playdough containers to trace my circles).
Very carefully cut your skewers to a size where they'd make good axles for the car - cut off the pointy side too, for safety, while you are at it.
With the pointy side of the skewer, puncture your circles in the middle of the circle (don't hole punch these - you want them to be a tight fit on the skewer so they roll/move with the axle).
Attach one wheel to each circle.
Single hole punch 4 holes for the axles - 2 in the front and 2 in the back (make the holes relatively straight across from each other).
Insert the axles and attach the other wheels.
Position your wheels so they aren't touching the side of the car (friction) or falling off of the axles. You want them to be as straight as possible.
Tape the ends of your axles, so your wheels don't pop off.
With left over skewer parts (axle "rejects"), tape a piece of skewer to your sail and attach it to your car. I found masking tape works best.
Mark and X or put a sticker where you want your child to blow if they are having problems directing their sail car.
This to play around with
Shape of the sail
Direction of the sail
Where to blow on the sail (use a mini fan if your child can't blow hard enough)
Weight in car
Weight of car (downsize if it's not working)
Race your car(s) - who can go fastest/furthest with one blow?
Navigate your car through a maze
Decorate your sail car (not sciency, but keeps them out of trouble for a few more minutes and make it theirs)
I'd love to hear feedback of how your home sail car project went.
I initially wanted to do vinegar + baking soda power boats (which we did too - another lesson), but we had some vinegar and baking soda left over and decided to try blowing up the balloon from the products of the reaction. We got the idea for this experiment from www.apple-cider-vinegar-benefits.com (though we did use normal vinegar). J was excited to have a balloon for his house.
The products of baking soda and vinegar are water (H2O) + carbon dioxide (CO2). The CO2 gas is what fills the balloon.
Surprising: Notice how the balloon bounces at the end. The balloon filled with CO2 from the chemical reaction is heavier than the reaction products of breathing air or helium (the two ways we would normally blow up balloons). It also sounds different as it bounces. Tie it off and experiment! See if your child can tell the differences between a balloon blown up with air from our lungs versus one blown up from the baking soda + vinegar experiment.
Here's what we did for the experiment:
*Fill the balloon with baking powder (we didn't measure - but it was enough to fill up the tip of the balloon).
*Fill the bottle 1/4 full of vinegar
*Attach the balloon to the top of the bottle without letting the baking soda fall into the bottle yet
*Tip the balloon so the baking soda falls into the vinegar
*Watch the reaction
*Comment on the reaction
Vary the amount of vinegar/baking soda/size of balloon and try again!
Edited 1/26/14 to Note: This post has become very popular with Pinterest. The pin links to this blog post, but the picture is not mine (after some research, I found it on Mom to 2 Posh Lil Divas and want to give them credit). For the record, I did not start that particular Pinterest pin with someone else's picture nor did I link it as an alternative to helium for party balloons. I apologize to disappoint. I want to ensure you that CO2 is HEAVIER/more dense than air, which means it's heavier/more dense than helium (as stated above in my original post). It will not float. The main point of this experiment is the chemical reaction between baking soda and vinegar. The CO2 gas fills up the balloon and the now water stays in the bottle. It is a fun and easy experiment for anyone who loves science. Enjoy!!
It's "C week" at J's preschool, and today was first lab meeting of the school year for me. I wanted treats for the new faces to think we're lots of fun (which we are). Not only are cookies are a great way to make friends, they are a great way to do (and eat) science. There's measuring, mixing, chemical reactions, heat transfer, fractions, etc. If you want to double the recipe, now you've added multiplication!!
J helped me make chocolate chip cookies for my lab yesterday. This is our fave recipe which we got from a Ghirardelli bag of chocolate chip cookies many moons ago. The key is 2 tsp of vanilla = delicious!
1 cup of butter (2 sticks) 2 ¼ cups flour
¾ cup sugar 1 tsp baking soda
¾ cup brown sugar (packed) ½ tsp salt
2 eggs 1 package of chocolate chips (12 oz - or about 2 cups)
2 tsp vanilla
Combine butter, sugar, and brown sugar until light and creamy
Add vanilla and eggs one at a time
In a separate bowl, combine the flour, baking soda, and salt
Stir the flour mixture slowly into the sugar mixture
Slowly add the chocolate chips
Drop cookie dough on cookie sheet (in desired amounts)
Bake at 375°F for ~ 8 minutes (watch carefully - we like them slightly under baked so they are softer longer)
Let cool and devour
Recipe makes ~4 dozen decent sized cookies
Variation: scoop dough into personal pan, bake 11 minutes, top with ice cream and enjoy your pizza cookie. The pan is extremely hot and not recommended for little ones. Please remove cookie from pan or cool before serving to little kids.
After I decided that our cookies last night were going to my lab, I asked J what he wanted to bring for "sharing time" this week. They are supposed to bring something that starts with the letter c. Bet you can't guess what his answer was. The Cookie Monster would be so proud.
We went with another recipe, just for variety. This is my next favorite recipe we found on a Funfetti box moons ago.
1 box Funfetti Cake mix - yes, it has to be Pillsbury - the other rainbow cake mixes smell like playdough when you make them into cookie dough and just don't taste right.
1/3 cup vegetable oil
Preheat oven to 350 deg F. Mix ingredients in a bowl. Scoop cookies out onto cookie sheet. Bake for 7 minutes (again a little on the under baked side). Makes 2 dozen Funfetti cookies.
*Cake cookies work really well for quickie desserts. The general rule is follow the ingredients on the cake box (any brand cake), without the water and minus an egg. Our next favorite is chocolate cake with chocolate chips added. We're real dessert people if you can't tell.
My co-worker reminded me of: I want to be a derivative so I can be tangent to your curves.
I promise a new post sometime soon. I was absent for the weekend (which is when I do my best work) due to a work meeting in Tahoe (I know, torture to have a lake view and be stuck in a room discussing work). J and I are working on cookies this week since he's supposed to bring a C word to his preschool sharing time. Cooking is totally science.