# Science Challenge

## Week of May 26, 2020

The goal of the NEWESD 101 Science Kit Cooperative is to send out weekly science challenges to our members. The challenges will sometimes be tailored to a grade level, or a more general challenge which can be adjusted or added to based on the grade level you are teaching.

If you are needing any science materials to show demos to your students during your virtual meetings, please let me know and we will do our best to accommodate any requests.

Thank you,

Beth

MATERIALS

• Strong balloon (teardrop shape works best)
• 2 plastic cups (or try more to up the challenge level) don't use glass!

PROCEDURE

1. After filling the balloon partially, hold two cups onto the sides of the balloon. Push them tightly against the balloon!

2. Continue to blow up the balloon and then let go of the two cups. *Be sure to keep a little pressure on each cup just after attaching it so that it will "take".

3. Be amazed as the two cups stick to the side of the balloon.

Explanation:

Physics is a branch of science that deals with forces, motion and energy. A force is a push or a pull, caused by people or other things like magnets or gravity. This experiment deals with a force called “pressure” which gives us a thing called a “vacuum.” A vacuum is formed when there is a low amount of pressure, which is determined by the amount of air in an area. If you push the air out of something it forms a vacuum, which other things try to fill up. When you keep the cups against the side of the balloon and continue to blow it up, the balloon pushes into the cups and forces air out and thus creates a vacuum. The air outside of the cup wants to fill this vacuum and since there is a nice seal around the edge of the cup (like a plunger on a smooth surface) it keeps the balloon tightly stuck together.

Experiment further:

Can you think of anything else you can experiment with in this lab? Different sized balloons? Other types of cups or bowls? What if you made the cups have a wet surface to them as you stick them to the balloon?

The walking water science experiment is great at any time of the year, but it is especially perfect for spring. I love doing rainbow activities in the spring, so this was a great addition to our rainbow theme activities.

If you are looking for simple science to do with the kids and something that will really WOW them, this is definitely one to try.

You only need a few simple supplies that you probably already have around the house.

Supplies Needed:

• Small plastic cups or glasses (clear are best)
• Paper towels (*read my tips below for picking the right ones)
• Food coloring in primary colors
• Water

* The pick-a-size paper towels are best because then you just use half sheets for each cup. If you only have full sheets, then cut them in half. I’ve also heard that more absorbent paper towels work better too. I buy the cheap store brand ones, and our water moved pretty quickly from cup to cup.

• Place 7 cups in a row and pour water in the 1st, 3rd, 5th, and 7th cup. My cups were about 3/4 full. I have since heard that fuller is better.
• Add 5 drops of red food coloring to the 1st cup and the 7th cup.
• Add 5 drops of yellow food coloring to the 3rd cup.
• Add 5 drops of blue food coloring to the 5th cup.

Doing the Walking Water Experiment

You want to try to use the same amount of food coloring in each cup. When I did this with my kids they did drop an extra one or two in since they can’t control it well, but I just added a drop or two more to the others to even it out.

1. Have students write down or draw in their science notebook their prediction of what they think will happen.
2. Take a half sheet of paper towel and fold it in half lengthwise and in half again lengthwise.
3. Trim off some of the length so that there isn’t too much excess paper towel that will stick up in the air between each cup. This will make the water walk more quickly.
4. Place one half of a rolled paper towel in the 1st cup and place the other half in the cup next to it. Then another paper towel from 2nd cup and into the 3rd cup. This continues until you have placed the last paper towel that drapes over from the 6th cup to the 7th cup.
5. Stare at the cups and watch what starts happening. You should quickly be able to see the colored water begin to crawl up the paper towel.

Keep checking back every couple of minutes. Soon you will be able to see that the water has crawled all the way up the paper towel and is beginning to walk back down into the empty cup next to it.

Since the cup on either side of an empty cup has colored water in it, the two colors begin to mix in the empty cup. So cool!

Keep coming back throughout the two hours or soon and observe what is happening. Be sure to record your observations in your science notebooks!

How this Science Experiment Works

The water moves up the paper towels through a process called capillary action. The paper towel is made from fibers and the water is able to travel through the gaps in the fibers. The gaps in the paper towel act like capillary tubes and pull the water upward. This is what helps water climb from a plant’s roots to the leaves at the top of the plant or tree.

The water is able to move upward against gravity because of the attractive forces between the water and the fibers in the paper towel.

## Grades 6-8: The Nude Egg

MATERIALS

• 2 eggs (really only need 1, but the 2nd is a spare in case one of them breaks)
• 2-pint plastic mixing bowl with lid
• Refrigerator
• Wooden spoon
• Coffee mug
• 5/8 cup corn syrup

PROCEDURE

1. Put both eggs in a mixing bowl. Cover with 1 pint of vinegar, put the lid on the bowl and put in the refrigerator.
2. After about 24 hours, carefully drain the vinegar (the shells will seem mostly eaten away at this point). Replace with 1 pint of fresh vinegar for another 24-hour bout.
3. At this point (48 hours from the start) remove the eggs with a wooden spoon (metal spoons will be too hard and could break the eggs), and carefully set them aside. Discard the vinegar under running water.
4. Write down your observations of the egg.
5. Take of the eggs and place in the coffee cup. Then cover it with corn syrup.
6. After another 24 hours, extract the egg with the wooden spoon and notice how flabby it has become.
7. Now discard the corn syrup, rinse the mug, and put the egg back in, this time covered with water.
8. After 24 hours (48 hours from step 3) you'll see that your egg is looking healthier again.

What Happened?

There are a few things going on here, all having to do with chemistry. To remove the shell and make the eggs "nude", you immersed them in vinegar. The acetic acid of the vinegar ate away the sodium-calcium carbonate crystals of the shell, leaving only the rubbery membrane surrounding the egg. That membrane is slightly permeable, allowing water to move from one area of higher concentration (the egg white, for example, is about 90 percent water) to one of lower concentration (corn syrup is about 25 percent water). When you replace the corn syrup in the coffee mug with water, you reverse this process.