"Egg"citing "Egg"speriments

“Egg”citing “Egg” speriments!

Eggs are so much fun to experiment with.  Their tough, yet fragile exterior is perfect for physics experiments.  The porous calcium carbonate shell is perfect for chemistry experiments.  Because an egg is a cell, it is perfect for biology experiments with osmosis.

Videos:

Physics - Solid vs. Liquid

Physics - Density

Chemistry - Natural Egg Dyes

Can you grow crystals?



Physics

  • Density
    • Eggs sink in regular water, what happens in salt water?
  • Solid vs liquid
    • Can you tell the difference between a boiled egg and a raw egg by spinning them?
  • Forces
    • Throw an egg at a solid surface, then at a free hanging curtain or towel.  What happens

Engineering

  • Can you build a device to safely land a dropped egg?

Chemistry

  • Natural egg dyes
    • Try dying eggs using natural dyes such as red cabbage, onion skins, berries and tea. 
  • Water haters
    • Use Hydrophobic materials such as oils and waxes to decorate eggs

Biology

  • Acid erosion 
    • What happens when an egg is soaked in vinegar overnight?
  • Osmosis
    • Once your shell is dissolved, what happens when your naked egg is placed in pure water, syrup, or salt water?

Physics - Density

Purpose: Can I get an egg to float in a glass of water?

Background:  Density is how much matter occupies a given area.  How much “stuff” is in a space. Density is a physical property of matter.  Solutions (when something dissolves in water) have a different density than pure water.

Procedure:

  • Fill a glass ⅔ full of water
  • Place a egg in the water
    • What does the egg do?
  • Slowly pour salt into the water and stir gently.  Continue until you see something happen.
    • What does the egg do?
  • Using the back of a spoon placed near the edge of the glass, gently pour pure water into the cup.
    • What does the egg do?

What happened?

Eggs are more dense than water because they have lots of “stuff” in them.  However, the more “stuff” (salt) I add to the water, the more dense the water becomes and the egg will float.  If careful not to mix, pure water can be added to the top and the egg will float between the layers. Add food coloring to the pure water, and you can observe the line where the pure water and salt water mix.

* Extra:  Egg shells are porous and allow air to enter the shell.  As an egg ages, more air will enter. If you compare a new egg and an old egg, the new egg will lay down in the water, and the old egg will stand up.  Use those old eggs for “egg”speriments!

Physics - Solid vs. Liquid

Purpose: Who will win the egg spin contest, the boiled egg or the raw egg?

Procedure:

With a friend or one in each hand, spin a boiled egg and a raw egg. Observe.

What happened?

The hard boiled egg spins for much longer (and faster) than the raw egg. This is because the inside is solid, so the entire thing is one solid mass. The raw egg has liquid on the inside, which is not attached to the shell. The liquid inside is much harder to spin, and it slows the egg down much faster.

Physics  - Forces:  

Purpose: Can I throw an egg and not have it break?

You can use raw or boiled eggs.  If raw, I suggest placing in a sandwich bag to minimize mess.

Procedure:  

  • Throw egg at a wall.  Observe 
  • Throw egg at a curtain or hanging towel (make sure there is plenty of space behind the curtain. Observe.

What happened?

This is a great example of Newton’s second law of motion. F=ma,  or rewritten as Ft=mv. This means that the longer the egg takes to stop (t), the less force is acting on the egg (F).  So even though the mass of the egg (m) and the speed of your throw (v) stays the same, the wall stops the egg fast (short time-t) and create a large Force, and the curtain slows the egg down (long time, low Force)

Great videos: https://www.youtube.com/watch?v=7RSUjxiZnME

https://www.youtube.com/watch?v=K0ra7479zBs

You can do this outside, or in the bathroom if you have a shower curtain

Egg Drop

Purpose:  Can you build a device to protect an egg dropped from a height?

Background:

Much like the last experiment, you want to “slow the egg down” down so that the force it experiences when it reaches the ground is low enough to keep it safe.

Most popular ways to do this is to increase air resistance or drag (parachute) or to increase the time it takes to stop (cushioning). Best choice is a little of both.

Engineering Design Process:

  • Ask a question
  • Imagine ideas
  • Make a plan
  • Create a solution
  • Test or experiment
  • Improve idea

Procedure: 

  • Decide where you are going to drop your egg. If using a parachute, the higher the better.
  • If a raw egg is used, wrap in plastic to reduce mess.
  • Build your device
  • Test

Tips:  You can add to the challenge by making your builder “purchase” supplies.  More desirable items have a higher price tag. I even charged per centimeter of string and tape. 

Items to use can include: string, tape, paper, straws, craft sticks, cotton balls, cups, tissue, etc.

Chemistry - Natural egg dyes

https://www.thekitchn.com/how-to-make-vibrant-naturally-dyed-easter-eggs-holiday-projects-from-the-kitchn-112957

Purpose : Color eggs using natural dyes and pigments.

Background:  Natural pigments from plants and bugs have long been used for textiles.  Those from edible plants are safe for food dyes..

Procedure: Go to the link and follow instructions. The creator uses onion skins, purple cabbage, beets, tumeric and red zinger tea.

My experience:  

Onion skins:  LOVE IT! Worked great!  I did boil the skins first and then boiled the eggs in the “dye”.  I wish I had used a purple onion too.

Cabbage dye:  Using the powder version was disappointing. I wish I had used fresh cabbage and boiled the eggs in the extract like with the onions.  I think that would have worked better.

I was using supplies I already had on hand, so didn’t have the opportunity to try berries,  turmeric, tea or beets. 

Regular food coloring with vinegar worked great.

Water Haters  - Hydrophilic Substances

Fun decorating:  Use waxes, or oils to “repel” the water based dye.

Most egg kits come with a clear or white crayon to write on eggs.  The wax in the crayon repels the dye and leaves that area clear. I have also used cooking oil, chapstick, and vaseline.  

With a vaseline, you can cover an area, dye, wipe off the vaseline and place it in a different color making multicolored eggs.

Biology - Acid Erosion

https://www.kidzone.ws/science/egg.htm

Purpose: What happens to an egg when placed in vinegar?

Background:  Egg shells are made of Calcium Carbonate.  This is the same material in our bones and teeth.  It is also the main component of limestone, marble and chalk.  It reacts with acids.

Procedure: 

  • In a cup, pour vinegar over egg and observe.
  • Next day, remove egg and observe

What happened?

When calcium carbonate (the eggshell) and acetic acid (the vinegar) combine, a chemical reaction takes place and carbon dioxide (a gas) is released. ... When you take the egg out of the vinegar it's soft because all of the carbon floated out of the egg in those little bubbles of carbon dioxide, and the calcium is dissolved in the water. The egg stays whole because there is a membrane inside the shell that does not dissolve.

Osmosis

Purpose - How does water move into and out of a cell?

Background: The egg is a cell.  It is surrounded by a cell membrane.  This membrane lets water and gasses in and out, but not bigger molecules like salt and sugar.

Procedure: Use eggs without shells  from previous experiment 

  • You can move one egg to different solutions, or experiment with several eggs
  • Place egg in pure water
    • Observe the next day
  • Place egg in syrup or high concentrated sugar solution
    • Observe the next day
  • Place egg in salt water solution
    • Observe the next day

What happened?

Osmosis is the free movement of water across a membrane.  Water will alway move toward the area with the highest concentration of solute (hypertonic) from the area of lowest concentration (hypotonic).

*Try this with gummy bears instead of eggs!

Bonus Easter Fun!

I like decorating “Easter Trees”.  This involves bringing a branch inside and decorating it with hanging eggs.  

A fun decoration for Easter, Christmas or just for fun.

Crystals from Borax.

Purpose: Can you grow crystals?

Materials: pipecleaner, insulated cup, Borax, string, craft stick.

Procedure:

  • Using a chenille stem (pipe cleaner) fold a desired shape.  Make sure it will fit in your container without touching the bottom or sides.
  • Almost fill your container with BOILING water.
  • Add Borax Powder and stir until the water will not dissolve any more (you will see some poder left on the bottom of the container. You can add food coloring if desired.
  • Suspend you shape in the water using a string and a craft stick or pencil.
  • Let sit overnight.

What happened?

Borax is the powder form of sodium tetraborate.  It is an ionic molecule that will dissolve in water.  If the water evaporates, it will become a solid again, and its molecular structure will form crystals.  Boiling water can dissolve more solute than cooler water. This is like making sweet tea by adding sugar to hot tea rather than cold tea. When you keep adding borax until it can’t dissolve any more, you make a supersaturated solution. As the water cools, it can’t hold as much of the borax, and crystals begin to form.  The slower the solution cools, the bigger the crystals, the faster it cools, the larger the crystals.

*Crystals will form in the bottom of your container.  I recommend using something disposable as they are very difficult to remove.

Pour supersaturated solution into egg shells to create “geodes”.