Mrs. Lozar’s STEM Lessons

S/T- science and Technology combined! This week, we will be learning a little bit about polymers and plastics. Polymers are a complex chain of molecules (tiny pieces of materials that are WAY too small for us to see without a very powerful microscope) that are very important for making plastics. The word “plastic” comes from a very old language called Greek, from the country Greece. The Greek word “plastikos” meant something was easy to shape. If you look around your house, I bet you can find hundreds of plastic things in all kinds of different shapes. See? Plastic is plastikos: easy to shape! Take a few minutes to do a little Plastic Scavenger Hunt around your house or yard. Try to find the following:

Something you can eat with, something you can drink from, something you would use to do your hair, something you could play with, something you could use to organize your desk, something you could keep food in… The list goes on! Find some bonus items that you didn’t even know were made of plastic!

 

Now, let’s make our own plastikos polymers, or molecules of a natural product (milk) that are easy to shape. Most plastics are made from oil products. Not today! We will be using the natural proteins (materials found in foods that are generally good for your body) in milk and a natural separation method to pull those proteins out of the liquids in milk.  

All you will need to do this is:

some milk, some vinegar (if you don’t have vinegar, try some lemon or lime juice), a heat-proof mug, paper towels, and if you have it, some food coloring or glitter (not necessary, just for fun).

 

Step 1: With parent supervision, heat about a cup of milk on the stove in a pan or in the microwave in a heat-proof mug. Heat the milk until it is just starting to steam. 

Step 2: Add about 4 teaspoons of vinegar to the hot milk and stir for a few seconds, until you start to see chains or blobs of protein (curds) separating from the liquid (whey). (PS: These are basically the same first two steps in making cheese! If you want to try making your own cheese at home, check out the recipe at the bottom of this lesson!)

Step 3: Layer 4-6 paper towels over a plate or washable surface and scoop as many of the curds as you can out of the whey onto the paper towels to drain. Use the paper towels to pat the curds dry, and knead them gently into a ball. 

Step 4: Now, if you have food coloring or glitter, you can add that to the ball of natural polymer! Knead again well, and then shape the polymer into different things! You can shape the polymer for up to an hour after draining it completely. If you leave it out to dry, you can paint it! It should dry completely in about two days.

Take photos of your polymer creations and share them with me at [email protected]

 

Homemade soft cheese: https://www.youtube.com/watch?v=utyzDUrd2Bw

Use paper towels or coffee filters instead of cheesecloth. Add some fun tasty ingredients while still soft to flavor your cheese! (Think crushed herbs, hot pepper flakes, salt, etc.)

 

E/M- engineering and math combined! The Egg Drop Challenge*! I’m sure you’ve heard of this one before. The challenge is simple: design and test an apparatus (fancy word for a thing you have built) to protect an egg from breaking when you drop it from different heights! This challenge helped when NASA engineers wanted to land a very fragile robot on Mars, believe it or not! The challenges of dropping something fragile without breaking it from a height are the same between you and your egg, and a NASA scientist and a Mars lander!

 

Using materials you have around the house or garage, build a structure around an egg. You can use straws, tape, paper towels, paper, cardboard, plastic bags, bubble wrap, etc. Get creative! Make sure you are thinking about what happens when things fall: you’ll want a structure that will be soft, but not too soft, and one that will keep the egg safely inside, and one that will soften the impact of landing. Some designs bounce or roll to do that, some might have parachutes, and some might be big squishy jackets for the egg. Keep in mind that the higher you drop your egg from, the more likely it will be to crack. Design accordingly! 

 

As you finish designing and building your protective apparatus for your egg, ask a family member for help with dropping it. Make sure you do this OUTDOORS. You may even want to lay down some plastic or a tarp over the surface you’ll be dropping the apparatus onto. Start by dropping the apparatus from a low height, like directly in front of you with your arm out straight. Make sure to measure and write down the height first! Next, if your egg survives, increase the drop height by increments of a six inches to a foot at a time. Keep track of your drop heights as you go! You can use the measurements for some math later! See if you can find the difference between the highest successful drop and the first (lowest) drop. Try adding all your drop heights up! See if you can convert each height in feet to inches! Try recording each drop height in both feet and inches in a data table! 

 

If your egg survives, make note of why you think your apparatus was so successful! What parts or materials seemed to do the best job of keeping your egg safe? If your apparatus was NOT successful, and sometimes failing is just part of being a scientist, think about WHY it wasn’t successful. Did the egg escape? Were the materials not strong enough? How could you change it or fix it if you could try again? If you have time, make some changes and go for another shot at it!

 

Take some pictures (even better, try slo-mo videos!) of your apparatus and drop attempts and send them to me at [email protected]

I love to see what you come up with! Stay well, and hope to see you soon!

 

*Egg Drop Challenge tips and videos: https://buggyandbuddy.com/stem-kids-egg-drop-project/