Showing posts with label Color mixing. Show all posts

Milk, soap, and food coloring



An easy experiment to show how fats move in liquids.

How does soap work?  What do hydrophilic and hydrophobic mean? This is a good experiment to start some of these discussions.  The fats in the milk are oil based (technically, they're called lipids) and the water in the milk is well, water.   Fats and oils are hydrophobic, which translates into "water fearing".  These fat molecules will clump together so that as few of them touch the water as possible.

Soap is a molecule that has a hydrophobic side and a hydrophilic side. (Hydrophillic ==  water loving. This is useful in our daily lives because the hydrophobic side of soap molecules will bind to oil and grease, and the hydrophilic side of the soap molecule will bind to the water molecules.  Then, when you wash your hands, as the soap gets washed away, the oils and grease are dragged away along with the soap.  

So, back to the experiment.
When you add soap,  you'll see food coloring expand away as all the fat molecules push the food coloring out of the way to get closer to the hydrophobic soap molecules.   Kids of all ages will enjoy "painting" with soap in the milk.  Older kids can start to grasp the concept of hydrophobic vs hydrophilic.

Materials:
Plate
Milk (skim milk works best, but whole milk will also work)
Half and half
Soap [not all soaps work.  Joy dish soap does]
Q-tips or Toothpicks
Food coloring

What I do:
I pour milk into one of the plates. Then, we drop a few drips of food coloring around the plate.  The kids dip their Q-tips into the soap and then poke one of the food coloring drops.  The result should be to see the food coloring expand away from the soap.

To make this an experiment, I get another plate and pour in half-and-half (or a milk with a higher fat content than the one I previously used.).  Before the kids dip their soap into the new plate, I ask them whether the colors will spread more or less than last time, and I ask them why.  This is called 'making a hypothesis' and is crucial to running an experiment.   Then I let them test it out.

What this activity teaches:
Scientific Method.  It's important to have your kids guess (make a hypothesis) about what will happen.  To encourage more experimentation,  ask them what they think would make the colors expand faster?  I.e does warm milk vs cold milk work?  What about adding more dish soap vs adding a little bit?  See what they come up with first before you give them hints.

Hydrophobicity.   Certain materials repel water.  This is a great experiment to start the conversation of what hydrophobicity is, and how it is useful in everyday life.

Painting 3D Puzzles

I picked up some cheap wooden puzzles, had my kids paint them, threw in some knowledge about anatomy and PRESTO: a fun and educational afternoon.



Materials:

  • wooden dinosaur puzzle (or substitute any wooden craft)
  • paint & paintbrushes
  • acrylic spray (to seal the washable paints)

What to do:

I setup a painting station and had each of my kids paint a 3D wooden dinosaur puzzle.   After painting, we let the puzzles dry (over nap time) and then came back to put the puzzle together.  I made W pop out his own puzzle pieces (improve that finger strength!) and together we tried to follow the instructions to put the pieces together.  This prompted discussions about bones, and body parts. Fortunately, a naked little brother was willing to serve as a model, and we had a quick anatomy lesson about the vertebrae in our spines.     

Easy modifications:
The wooden dinosaur puzzles are perfect for any child (and adult) who loves our ancient friends. However, if you can't get these puzzle pieces, you can substitute any wooden craft.   A craft in which a child needs to put the final pieces together supports spatial reasoning.

Tips and Tricks:
  • I now use acrylic spray to seal anything with washable paints, because getting water on the pieces will make them run.
  • The instructions were difficult to understand.  This was something I needed to help W with, and it wasn't easy for me.  Eventually, I figured out that the numbers on each piece corresponded to the attaching pieces.

This activity teaches:

Colors and Color mixing.  You may have noticed how R became really excited to see blue and red become purple.  W was excited to create and name his new colors.  This part was especially exciting to see, because it meant he was becoming curious.  He started experimenting to see what new colors he could make.

 Spatial reasoning. Figuring out where the puzzle pieces go in 3D as well as 2D space trains a child's spatial reasoning.  If puzzles are unavailable, you can do the same with any craft that involves building or putting together pieces to create a final project,  like a birdhouse.

 Anatomy and body parts. Because the puzzle involved skeletal pieces, we could start a discussion on where certain bones in the body are located

 Finger strength.  Finger strength is important for fine motor skills.  It's necessary for proper pencil grip, as well as hanging on to monkey bars and climbing walls.

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