Wednesday, May 28, 2014

Simple (and Scientific) Homemade Ice Cream

Our family doesn't currently own a car so all of our travel is done via our own two feet, biking, and the occasional bus ride. On really hot days this causes us to ravenously burst through the door in search of cold stuff to shove into our mouths.
I came across this fantastic recipe for homemade ice cream last year. We have enjoyed it several times both as a family and in our Science Kiddo classes. The thing I like the most about about this ice cream is that you don't need any special equipment or ingredients to make it. Plus, it is a delicious and refreshing way to learn some science!

To make any variety of homemade ice cream you need to partially freeze your milk or cream. Water freezes at 32°F, but because milk contains proteins and fat it freezes at a lower temperature. This means that trying to freeze milk with ice cubes won't work. You need to add a special ingredient to your ice cubes to make a mixture that is colder even than ice alone. Ready for the secret ingredient? I'll give you a few clues. It's white. It's something almost everyone has in their kitchen. It tastes yummy on popcorn with butter. It's....SALT!

We talked about the magical science of how salt and ice cubes work when we did our Fishing for Ice experiment and when we made our delicious fruity slush. When you add salt to ice, it lowers the freezing point of the ice, making it melt. You are left with a salty-icy-watery mixture that is much colder than 32°F. The temperature of your salty mixture is close to 0°F! (You can verify this with a thermometer.) This temperature is cold enough to freeze milk, thus enabling you to enjoy yummy homemade ice cream in less than 10 minutes. Put it atop your morning waffle if you so desire.
Total Time: 10 minutes or less
Difficulty: The one trick with this experiment is making sure you don't contaminate your ice cream mixture with your salty water. This leads to yuckiness.

Materials You Need:
One small Ziploc baggie (quart or sandwich size)
1/2 C. milk (whole works best, but any variety will be fine)
1 Tbsp. sugar
1/4 tsp. vanilla
One gallon-size Ziploc bag
8-10 C. Ice
6 Tbsp. salt

Directions:
  • Add milk, sugar, and vanilla to the small baggie. Seal the bag, being careful to release excess air.
  • Add ice and salt to the bigger baggie.
  • Place the small baggie into the large bag of ice and salt. Seal the large bag.
  • Shake for about 5 minutes or until the milk mixture turns into a soft solid.
  • This is the tricky part: Open up the large bag, remove the small bag and rinse it off quickly in cold water (pay special attention to rinsing off the opening). You don't want any of the salt water getting into your sweet and creamy ice cream!
  • Either grab a spoon and eat your ice cream right out of the bag, or pour your ice cream into a bowl. Either way, eat it and enjoy!
Print These Instructions

Sunday, May 25, 2014

Fruity Ice Slush

Did you know you can make your own delicious slush drink without a freezer? This is the ideal experiment to do on a hot summer day when all you want to eat is something freezing cold and delicious. With lots of those days up ahead, we hope you really enjoy this tasty slushy science!
I pulled this idea from one of our favorite experiment books, 50 Science Things to Make & Do. I love this book because it contains tons of simple science ideas with easy-to-follow instructions. Even my four-year-old can do many of the experiments on his own :)

Total Time: About two hours.
Difficulty: With just a few ingredients and some simple stirring, this is one of our safest and easiest experiments yet!

Materials You Need:
Mixing Bowl
Ice
3 Tbsp. Salt
Fruit Juice (any variety should work just fine)
Spoon

Directions:
  • Fill your mixing bowl with ice.
  • Add the salt and stir it in.
  • Place a glass upright in the middle of the ice and fill it halfway with juice.
  • Stir the juice every 10 minutes for about an hour and a half.
  • Stir it every 5 minutes for another half hour until it turns slushy.
  • Eat and enjoy!
Print These Instructions

Our Fishing for Ice experiment and Easy Homemade Ice Cream involve the same science that makes the fruit drink in this experiment turn from liquid to solid without the aid of a freezer. When you add salt to ice it lowers the freezing point, making the salty icy mixture colder than ice alone. If you have a thermometer you can verify this fact. Ice freezes at 32°F, but when you add salt the ice melts and the mixture gets down to around 0°F. This is cold enough to freeze juice! Stirring the juice frequently ensures that the frozen parts mix with the liquidy parts, making a yummy slushy mix. If you leave your juice long enough it will freeze solid! Maybe next time we will try making our own popsicles this way...

Thursday, May 15, 2014

Ant Attack!

Sometimes science experiments are complicated and require a lot of materials and detailed instructions. However, science experiments can also be incredibly simple while being just as fun and interesting as the complicated projects.

This experiment is very simple and basically takes no time at all. All you need to do is cut up an apple and place one slice near some ants (probably best to place the apple several feet away from your house so the ants don't come inside!). It's preferable if the apple is on some concrete so you can see the trails that the ants follow.

Watch what the ants do. Do they carry pieces of the apple away? Where do they carry the pieces? Do the ants follow the same path every time? Do they help each other or do they fight?

Check your apple slice after one hour. Are there more ants? What are they doing?

What happens if you move the apple an inch or two to the side? What do the ants do?

Watching how ants work together can be fascinating. Ants leave trails of chemicals called pheromones that alert other members of the colony that there is food on the path. This is why each member of the colony continuously walks the same route to the food and back to their nest. What happens if you place a leaf or a rock in the middle of their path?

This experiment will turn a lazy summer afternoon into an exciting discovery of ants and their behavior. Enjoy!

Thanks to 50 Science Things to Make & Do for this fantastic idea!

Thursday, April 17, 2014

How to Dye Eggs Naturally Using Acid/Base Chemistry

One of the things I anticipate most about this season is dying eggs with my family. It's one of those things that is always fun no matter how old you get. This year we added another fun dimension to our egg-dying party by incorporating acid/base chemistry into it. For those of you who love science AND love doing things naturally (even organically!), this is the perfect activity for you.
The star of this show is red cabbage. It contains a chemical called anthocyanin that changes color depending on the acidity of its environment. This means it is a pH-indicator, a gauge that tells you how acidic or basic the surrounding environment is. Red cabbage is purple in a pH-neutral environment, but it turns pink in an acidic environment and bluish-green in a basic environment. We recently did another experiment with red cabbage where we froze cabbage-water into ice cubes and tested the acidity of different solutions. It's the same chemistry, just a different way to see it.

Total Time: This experiment takes awhile, though you don't have to actively be doing anything for most of the time. Allow about 40 minutes to boil the eggs and cabbage and at least 12-18 hours for the eggs to sit in the fridge in the cabbage solution. Painting the eggs only takes 10-20 minutes at the end.
Safety Concerns: As always, be careful when boiling things with kids around. Use caution when cooking and handling the hot eggs and cabbage.

Materials You Need:
One half of a head of red cabbage
One dozen large eggs
Slotted spoon
Lemon juice or vinegar
Baking soda
Q-tips or paint brushes to paint the eggs

Directions:
To prepare the eggs:
  1. Place eggs in a large pot in a single layer.
  2. Chop up your cabbage into small pieces and throw them into the pot with the eggs. Add enough cold water to cover everything by one inch.
  3. Bring the cabbage/eggs/water mixture to a boil. Remove from burner and cover the pot.
  4. Let your mixture stand for about 12 minutes for large eggs (9 minutes for medium eggs, 15 minutes for extra large eggs).
  5. Using a slotted spoon, remove your eggs from the pot and cool completely under cold running water or in a bowl of ice water. They will most likely still be very white at this point.
  6. Refrigerate your eggs. Once your cabbage water has cooled to room temperature, place your eggs back into the pot and refrigerate everything together. Make sure the eggs are completely submerged in the water for best color.
  7. Leave your mixture in the refrigerator overnight.
 To paint your eggs:
  1. Use a spoon to scoop your eggs out of the cabbage mixture. Feel free to rinse them off and pat them dry. They should be some shade of bluish-purple (depending on how acidic your tap water is!).
  2. Pour some lemon juice or vinegar into a small cup (this is your acid).
  3. In another cup mix 1/2 tsp baking soda with enough water to dissolve it (this is your base).
  4. Using your Q-tips or paint brushes, paint your eggs! Watch as your eggs change from blue to pink when you paint with lemon juice and from blue to greenish-blue when you paint with your baking soda solution (this may not show up well until the eggs are dry again).
  5. Feel free to try painting your eggs with other solutions from around the house to see what happens. Some ideas to try are washing soda, cream of tartar, and antacids. If your egg turns pink you know the solution is acidic, if it turns green you know it's basic!
Something interesting that I noted was that the cabbage solution turned out very blue this time, whereas last time we did this experiment it was beet red. We moved to a different county since last time, so does that mean our drinking water is more basic on this end of the city? Or is it a difference in the cabbage I purchased each time? I don't know, but I think it's definitely worth finding out!

Print These Instructions
You can see the whitish-pink spots where we painted with lemon juice. On the right of the egg you can see it's a little bit green, which is where we painted with baking soda.
Thanks to the Kitchen Pantry Scientist for this awesome idea!

Wednesday, April 16, 2014

DIY Window Gel Clings

Window gel stickers? Window jellies? Window gels? I really don't know what they are called, but my kids love them. How would you like to make your own gel clings that are not only cute, but also edible? I thought so.

Now before you think I have gone too artsy on the Science Kiddo, just stay tuned. There is a ton of science your kids can learn from this in addition to it being a great creative outlet and fun activity for you to do as a family.

It's really simple and only takes a few ingredients. Our window jellies turned out beautiful and fun, just in time to catch the sun's warm spring rays in our window.

Total Time: About 20-30 minutes
Safety Concerns: You will need to boil water for this. Just watch your kids around hot water and the resulting hot gelatin. Let it cool a bit before your kids get close.

Materials You Need:

Four cups of boiling water
Six packets of unflavored gelatin
Food coloring and glitter of your choice
A toothpick
One large cookie sheet with a rim or two 9 x 13 casserole dishes
Cookie cutters
Spatula


Directions:

  • Add the gelatin to the hot water. Stir to make sure it all dissolves and spoon out any bubbles.
  • Pour your mixture into whatever containers you want. You want it to be about half an inch thick. It doesn't have to be exact, but it is best if it is level. Bowls won't work very well since the gelatin won't be a uniform depth.
  • Once gelatin is cooled a bit, but before it hardens (you have about a 45-minute window here) have fun dropping food coloring into your gel and swirling it around with your toothpick. Sprinkle it with glitter if you desire.
  • Let the gelatin harden. It should only take 30-60 minutes. Since it's super-concentrated it hardens quickly without being in the refrigerator.
  • Once it has set use cookie cutters to cut out shapes or cut out your own shapes using a butter knife.
  • Use a spatula to lift your gel shapes out of the pan. Don't worry if they tear because you can simply mold them back together. Stick them to your windows and enjoy!
Print These Instructions

Easy, right? One thing I love about decorating the gelatin is that it is much more viscous, or thicker, than water. This means that you can decorate each corner differently and the colors/glitter won't run into each other. You can customize the colors and shapes for whatever holiday or season you want!

If you want to incorporate more science into this activity you could pour some water into a pan, drop colors into it, and compare how it behaves differently from the gelatin mixture. Then do the same thing with vegetable oil. (We did this in our Color Bombs experiment.) You could also observe how your window gels evaporate after a few days on the window, leaving behind paper-thin dry shapes.
Note: You probably won't be able to take these jellies off your window and put them back on more than a few times before they tear beyond repair. They are slightly more delicate than the window gels you buy at the dollar store.

Wednesday, April 9, 2014

Which One Will Freeze the Fastest?

This article was contributed by Jen, a homeschooling mom of three from Beaverton, Oregon. In February the Portland area was hit by a huge snowstorm for these parts and the entire city basically shut down. Jen did this awesome experiment with her kids while they were hunkered down at home.

We took advantage of the snow storm and subfreezing temperature in February to have a little Science Snow Fun! What we did was fill balloons (and a few random party bags) up with water, added some food coloring, and laid them out in different locations outside. 

You’ll see the bags and a balloon on our back deck:
And a few balloons set up on/around a table in the backyard. Will had a clever idea to suspend one balloon from the table itself - see the light blue balloon in the picture below :)
Enter the hypothesis!! We guessed that the balloon suspended in the cold air would freeze the best, as the balloons surrounded by snow (not unlike a snow cave) would stay closer to the 32 degree mark. We weren’t sure how much the wood from the deck would affect the balloons.

In all fairness, to have a truly scientific experiment, we should have filled the balloons all the same size, but without a hose, we were just lucky to get the water in the balloon in the first place :) 

We waited overnight - and then examined each of our balloons/bags.

The bags up on the deck formed crystals, but were mostly liquid:
This was the balloon that had its own snow cave…. Logan is going to open it up… and you’ll see the lesson we learned the hard way: don’t dye balloons with red food coloring…
Not a good choice of color… sorry :(

Moving on!! Here’s Logan taking down the balloon from the table - check out how much snow is actually ON the table!!! 
The balloon that was suspended from the air was the ice “balloon” on the right. The one on the left was a balloon that was on the table, BUT did not have a snow cave around it to keep it “warm” and so it too because an ice balloon :) 
Conclusion: The balloon on the metal table and the one hanging from it froze the best. The balloon and bags that were sitting on the wooden deck hardly froze at all. We think this is because the balloons on the table received cold circulating air from all sides. Plus, metal is a better conductor than wood, meaning that the balloon on the metal table got colder than the balloon that was sitting on the wooden deck.
 
So much fun!!

I love that Jen and her kids used their time at home to have some fun, ask some scientific questions, and discover some new things together. What are some scientific things your family has learned this winter?

Tuesday, April 8, 2014

Magic Balloon Bottle

We love to blow things up around here. But what about sucking things in? This is an experiment that often surprises the kiddos because they don't often get to see a balloon get pulled inside out. Ready to startle the kids? Let's get started.

Total Time: About 10-15 minutes
Safety Concerns: Be careful around hot water. At one point the glass bottle does get warm from the hot water, so just make sure that it's not so hot as to burn fingers. Use oven mits if necessary.

Materials You Need:
A glass bottle
Warm water
A balloon with the neck cut off (This is apparently necessary. We tried it several times without cutting the neck off and it didn't work.)
Large bowl full of ice water

Directions:
  • Fill the glass bottle with warm water. We heated the water up on the stove and then poured it into the bottle, but hot tap water is probably fine, too. No need to use boiling hot water. See Safety Concerns above.
  • Leave the bottle for a few minutes so that it gets warm. Pour out the water.
  • Stretch the balloon over the top of the bottle.
  • Stand the bottle in the bowl of cold water.
  • What happens to the balloon?
So what is going on here?

When air is heated up the molecules in the air have more energy to bounce around. This increases the pressure, or expands the air. When air gets colder the molecules slow down and move less, which decreases the pressure and makes the air contract, or get smaller.

In this experiment we first filled the bottle with warm water, which heated up the bottle and the air inside. As we cooled the bottle down, the air inside cooled down and contracted, or took up less space. To make up the extra room in the bottle, air from outside pushed into the bottle, which pushed the balloon into the bottle as well. Another way to explain this is to say that we created a vacuum in the bottle, which sucked the balloon into it.

Cool, right? Try this with different sized containers, get really scientific and use a thermometer to measure the temperature of the water, or keep track of how long you need to cool down the bottle before the balloon gets sucked into it. Have fun!

Print These Instructions

Wednesday, April 2, 2014

Science Kiddo Expo - Spring 2014

This week we did two big Science Kiddo Expo days to promote the importance of science learning for young children. It couldn't have gone any better! Thank you to the Harrison Hill Swap 'n' Play for hosting us and for everyone who brought their kids and participated. We all had a fantastic time playing and learning science.

Here are a few of the highlights:

Of course we had to do our most impressive demo with dry ice, water, and tons of bubbles! This is always a huge hit. The kids couldn't keep their hands out of it!
Using baking soda and vinegar to blow up a balloon
Learning about the balance
We also did the magic inside-out-balloon, had loads of fun with magnets, went fishing for ice, and blasted balloon rockets. So fun!