Today was one of those days when we totally scrapped our plans and just had fun. The kids have been begging for a "science day," so we pulled out the neglected NOEO kits and learned about density, volume, acids, bases, and other cool stuff!
The kids started by building a spring scale. Isn't it cool? We provided the cereal box and NOEO provided paper clips, elastic string, and a little cup.
Then we had to calibrate the scale, by adding one gram discs and marking the top of the bowl as each disc caused the elastic to stretch. (We found this very challenging, and ended up declaring our scale "close enough" so we could get on with the rest of the experiment!)
What do you predict would weigh more? The cork or the little metal Viking? Really? Even though the cork is way bigger than the Viking?
So large objects can weigh less than small ones? Yup! The cork may have more volume, but the Viking has more density!
The NOEO instructions suggested lining up a variety of small objects by size and predicting which would be the heaviest. We weighed a fortune cookie, a packet of soy sauce (Chinese take-out last night!), a chip clip, a cork, a piece of bubble gum, a small plastic horse, a sugar cube, and the little Viking.
This chunk of fool's gold was the maximum weight our scale could take.
We talked about how volume is volume, even if the container is shaped differently. A cup of water in a skinny cup is the same as a cup of water in a wide cup. (A while back, we did another experiment to illustrate volume v. density. We took two identical jars and put cotton balls in them. In one jar, we just lightly dropped the cotton balls in. In the second jar, we pushed as many cotton balls as we could in. The jars were the same volume, but in the second jar, the cotton balls were much more dense.)
I had the kids look for the volume on some labels. They noticed that most of our products have the volume listed in English and metric. I noticed that we are nearly out of syrup!
Which is more dense, the water or the Ivory soap? How can we tell?
Just for kicks, we put chunks of Ivory in the microwave, a crazy trick I saw on The Scientific Homeschool. It puffed up like marshmallow fluff, then turned to crunchy soap flakes.
(FYI: If you try this experiment, don't put the bowl in your dishwasher! Even though I rinsed it out, the bowl I used left a white film on all the other dishes and I had to run them again. Use something disposable that you can just toss in the recycling bin afterwards.)
This is colored water and corn oil. Which is more dense?
This test tube contains corn syrup on the bottom, colored water in the middle, and oil on the top. It's hard to see, but there is a peppercorn resting on the surface of the water. It's more dense than the oil, but less dense than the water, so it floats on the water. There are also little bits of red plastic floating on the oil; they didn't sink at all so they must be less dense than oil.
Our second NOEO lesson was on acids and bases. We went to a class on this topic last year, so it was kind of a review for us. But it was interesting! We tested three kinds of vinegar, plain water, sugar water, baking soda water, Cran-Grape, and lemon juice.
NOEO includes some information about acid rain. We decided to grab some snow off our back porch and see if it was acidic. Thankfully, it was totally neutral!
To finish up our science day, we did a fun experiment from Science Is... by Susan V. Bosak. We dropped marbles into water, shampoo, and corn syrup to see which would reach the bottom last. Which marble would you pick?