Water density and floating egg experiment

This experiment was suggested by a fan of Nerdy Science, Stephanie, as a fun experiment to do with eggs.

Experimental Questions:
Are eggs denser than plain water? Are eggs denser than salt water?

Background:
When things are more dense than water, they sink when placed in water. If they are less dense than water, they float.

Test your knowledge to form your hypothesis (educated "guess"):
Gather a few items from around the house and see if they sink or if they float. Which items are more dense than water? Which items are less dense than water? Can you guess what will happen to the egg when placed in water? Do you think anything different will happen to the egg when placed in salt water?

Materials:
-1 glass of plain tap water
-1 glass of plain tap water + salt (amount varies)
-1 or 2 raw eggs, non-cracked

Methods:
-Gently drop an egg into the tap water. What happened?
-Gently drop an egg into the salt water. What happened?
-Add more salt to the salt water. Did that change any of your results?

Our Results:
Our egg in plain water sank to the bottom of the cup.

Our first attempt at the salt water resulted in our egg being neutrally buoyant and hovering above the bottom of the cup:

So, we took a guess about what would happen if we added more salt. Based on the semi-floating egg above result, J guessed that the egg will "really float" when we added more salt.

He was right!

Conclusions (via J's own words):
-"Water can't hold up the egg."
-"Water with salt CAN hold up the egg. Science is amazing!"

The egg is more dense than plain water, but with enough salt, the egg is less dense than salt water.

Thanks, Stephanie, for this fun addition to our egg experiments!

An Awesome Review, Thanks Stroller Hikes

One day, when Nerdy Science was a baby (ie. Nerdy Baby), I was at the park with my son trying to get the wiggles out after school, before coming home for dinner. I ran into a friend and was telling her about this brand new blog adventure and how I was getting little sleep between setting it up and J waking up between 4-5a (it was pretty awful). I guess the passion for this science blog showed through my words (and maybe my baggy eyes). Another person playing with her daughter happened to overhear and told me about Stroller Hikes, a non-profit organization that encourages family outdoor activities together. She had done some web work for the group and put me in touch with the organizer. I was hoping to help write some of their science curricula, but it turned out that I went into hyper drive with the Pepsi Refresh campaign, then the grant, and now Science Saturdays (sorry, Stroller Hikes). They still have tons of information for parents about fun activities in the outdoors, including science activities. I highly suggest checking them out whether you are a Bay Area Local or not.

Since our Science Saturdays happen to take place in local parks, I decided to see if they would be interested in our science activities. They wrote a fantastic blurb about Nerdy Science's Science Saturdays on their website. I look forward to meeting more parents as the activities continue. If you would like to join in on the Science Saturday fun, please email me using the link to the left and I'll add you to our email list. Since we depend on weather and our family's health, we can only predict about 5 days in advance when the next Science Saturday will be. So far, April's activity is looking like April 20th or 27th. Stay tuned.

The Magnet Detectives

Science Saturdays for 2013 started off with a bang! The weather brought us 70 degrees and partly cloudy, and it was a perfect morning for being outside and having some science fun!

Our lesson this month was on materials things are made out of. There are lots of materials on earth, but only a select few are attracted to magnets - those materials have iron in them (think steels). Many kids hypothesize that all metals stick to magnets. This is a good educated guess, but it's wrong (and it's ok to be wrong at this level of science understanding - that's how we learn).

I got the idea to bury things in the sandbox from J's preschool, where they bury paper/sequence in their school playground and the kids go find "treasures" (which we cannot throw away no matter how many times they fall on the floor and the Roomba threatens to vacuum them up).

The materials I buried:

• Matchbox cars
• Tin/jar lids (ie. Altoid boxes)
• Sponges
• Aluminum foil
• Cheap Ikea baby silverware spoons
• Milk caps
• Candles
• Popsicle sticks
• Straws
• Balloons
• Marbles
• Pennies
• Bobby pins
• Paper clips
• Pipe cleaners
• Army men
• Rubber bands
• Giant metal washers
• Colored plastic chips with a metal band around them (they came in a magnet activity)

*note, I stayed away from anything sharp since burying nails in a public playground doesn't sit well with me as a mom.

As the kids dug up a treasure, they had to say what they thought it was made out of and whether or not it'll be attracted to a magnet. A good way to test would be to place the item on top of the magnet, then flip the magnet over. If the item sticks, it's attracted. If not, it's made up of a different material.

For those who were still interested in playing science after 15 minutes (seriously people, sometimes science day feels like a flash mob, but the adrenaline rush is awesome and the kids always have fun), I showed them that the magnet itself doesn't stick to cardboard, but the magnet has a field which can go through cardboard. I made up a dancing bug activity on the fly. It went over super well. All you need: a few pipe cleaners, a magnet, and a piece of cardboard. Place the magnet under the cardboard and watch your pipe cleaner bug move magically!

Big J (my husband), came up with the game, how many washers can your magnet hold. I also heard they were playing pass the washers with their magnetic wands as they ran around the playground.

One more game with magnets on playgrounds: hide the magnet. It's like hide-n-seek, only you're hiding the magnet (hopefully a larger, visible one) somewhere on the playground (preferably on a metal structure to narrow things down). Then the kids have to find it based on their knowledge of where they think it could be sticking.

Thanks for everyone who came to our fun Science Saturday. If you live in the Bay Area and would like to join us, shoot me an email using the link over to the left, and I'll add you to the email list for Science Saturdays. I try to hold them at least once a month and give at least a 5 day notice of events. They do depend on weather and our overall family's health (we love sharing, but not the flu).

**These are the magnetic wands we used: Learning Resources Magnetic Wands**

Another ivillage highlight: Balloon Racers

ivillage (NBC Universal's parenting website) recycled the Balloon Racers piece from this past summer (page 6) for a piece on reusing cardboard for fun. It's nice to have new viewers to the blog. They link to the preschool tag, so you have to scroll a bit to get to the balloon racers we did in April 2012.

Here's a better link if you are looking for instructions: balloon racers.

Enjoy your racing!

Egg Maracas

We're approaching Easter. It's a good time to reiterate how much I hate eating just eggs, but I have no problem with using eggs for science experiments. Last year's experiments were fairly extensive, but I'll have some new ones to add this year.

The first one comes from an idea listed on Kiwi Crate's DIY website, Egg Maracas. I enjoyed the idea because somehow we end up with collections of these plastic eggs, and it feels so wasteful to just toss them.

Music is very science oriented. Sound, sound waves, pitch, tone, rhythm, etc all have their place in science. I never played a musical instrument, and I was banned from my elementary school chorus. I stuck to dance, which is deeply rooted in music, in particular rhythm and patterns.

Anyways, the basic maraca is easy to make. For each maraca, we used:
- A plastic egg
- Rice
- 2 matching plastic spoons (we collect these too)
- Masking tape (nothing fancy on our end)

What we did:
1. We filled the plastic eggs with rice. Since we had 3 eggs, we decided to use 3 different amounts of rice to see how that would affect the sound.
2. We taped the eggs shut since they seem to easily split open.
3. We placed the spoons so they cupped the egg and the handles met at the bottom. We needed two sets of hands, one to hold the spoons and the egg and one to tape.
4. While one person holds the spoons and egg in place, the other person tapes around the spoons and the egg (just once should be fine) and down where the handles meet.
5. We covered the whole thing (except Big J's maraca) with tape.
6. We decorated the tape with Sharpies (note that rubbing alcohol takes off Sharpie marker in case you have reservations about handing your little one a permanent marker). Crayola rubs off too easily when placed on masking tape.

Lil J, Big J, and my maracas (from L-R)

Science:
-Guess which egg has the most rice? You can weigh them or listen to the sound difference. A fuller egg should sound deeper.
- Play a "Simon" like rhythm game where you give a pattern of shakes and your kid repeats them. Get more complex as you go. Let your kid be the leader too.
- Use other items instead of rice. How do beans or pennies sound in your shaker?


**I apologize for the poor lighting and Craisins (and much more you don't see) on our kitchen floor. We were invaded by ants, so what's normally in our cupboards is sprawled on our counters, table, and floors. Good news was this experiment was able to be done in a very small space (and impromptu - right before bed).