Saturday, April 10, 2010

M4 - April Week 1

Our first week of April was rather eggy! Lots of eggs around, so that's mostly what we focused on. Goodness, we could probably spend several years on eggs and never get to a good stopping point.

That being said, let's get started with what we did:


Density and Floating Properties of Eggs

We decided to look at the floating properties of eggs - in tap water and then in brine.  (Check for how this is *supposed* to work.  

But for some reason we seem to fail at egg experiments!  Our Egg in a Bottle experiment failed during our "E" adventures, and this one failed, too.  Great way to start, huh?

First you fill a jar half way with tap water.  Then you put an egg in it.  The egg is *supposed* to sink because it is denser than tap water.  Ours didn't - it floated.

Moving on.  Then you pour salt into the tap water and mix it to raise the density of the water.  Maybe the egg is just supposed to float higher?  It doesn't - it just keeps floating at the same level.

So you pour more salt in, and more salt in, until the whole container is used up.  It still keeps floating at the same level.

Moving on.  Add a few drops of food coloring to a glass of cold tap water and pour it on top.  The egg should stay suspended in the middle - on top of the brine, but at the bottom of the colored tap water.  Nope - it bobs to the top.

It wasn't a complete loss, though.  Mommy did research to figure out that STALE eggs float, since egg shells are slightly porous and allow a large air cell to form over time .  So obviously our eggs are stale and need to be thrown out.  Here's the test for fresh eggs (thanks, What's Cooking America):

Carefully lower your eggs into fresh cold water (do not use salted water) using a spoon:
  • If the egg stay at the bottom - it is fresh.
  • If the egg is at an angle on the bottom - it is still fresh and good to eat.
  • If the egg stands on its pointed end at the bottom - it is still safe to eat but best used for baking and making hard-cooked eggs.
  • If the egg floats - it's stale and best discarded.
Lesson learned:  in life, the lesson you expect to learn isn't necessarily the one you WILL learn.

We DID do a quick experiment using a stale egg (that floats) and a HEAVY egg-shaped quartz rock (that didn't float) - so I could see how something heavy actually DOES sink.  Unless it has a gas/air pocket it in somewhere, or something.


Soft-Shelled Eggs

This one is easy (and it doesn't matter if the egg is stale :).  First you feel how hard an egg shell is (we used a hard-boiled egg).

Try a little taste of vinegar.  Yucky!  Hard to believe ketchup is made with that stuff...

Put the egg in a small jar with a cup of vinegar.  It gets all bubbly, like a fizzy drink (soda).  That's the acetic acid of the vinegar causing the calcium carbonate of the egg shell to release carbon dioxide (the same stuff in fizzy drink that makes you burp), or something like that...

Check back the next day.  All the carbon is gone from the egg, and the egg shell is now soft and squishy!

(More ideas with this experiment on KidZone.)


Oviparous Animals 

We did lots of quizzing about which animals are oviparous.  At first I thought this was easy - birds hatch from eggs, and all the other animals come from out of their mommies.  But after I learned that things like turtles and crocodiles and dinosaurs come from eggs, too, I got all confused.  It's complicated!

So we went through a bunch of animal cards, and then Mommy grabbed lots of animal books (farm books, zoo books, etc) from the shelf, and we paged through them and decided which were oviparous and and which ones not.  I think I'm getting the hang of it!

Did you know that frog eggs are really cool and transparent?  Not opaque, like chicken eggs.  Very cool.

Here are a few books we read:

Here's a cool idea for using little animals (instead of pictures) for this activity at Arts and Crofts.

And if you want a whole week of activities, check out Hubbard's Cupboard.

And Me


Did you know skin is the largest human organ?  So that's where we started.  First, Mommy traced me (my skin) on a sheet of butcher paper.  We'll cut this out and use it as a base for positioning all the other body parts.  I LOVE being traced.

Then I practiced touching all kinds of opposite things that mommy had put into matching colored eggs.  Here are some of them:
  • Pliant play doh/sharp thumb tack
  • Soft cotton/hard rock tile
  • Wet wipe/dry tissue
  • Sticky peanut butter/powdery sugar


Ticia said...

Hee hee, we did eggs too this week. But, you did so much more, or at least different. Very cool!