Tuesday, April 19, 2011

Water Exploration with Kindergarten

These are a set of experiments that I did with the kindergarten last year.  I will be doing them again this week.  They were popular with both the kids and the teachers.  I will describe them here, and if you want the write-ups just leave a comment and your email and I will send it to you.  I have not done the classic sink and float here, which is something that the teachers do in class with the students.  I have tried to come up with other experiments that will get the students thinking and having fun.

First, we do a small sink and float with a twist.  I take a small square of tin foil and fold it loosely and float it in the water.  It does float.  You can then take the foil and fold it tightly and it will sink like a rock.  You then ask the kids what happened, and why it happened.  The bigger piece of foil floats because of its greater surface area.  When folded smaller and tighter, it is denser and has less surface area and sinks.  Because of the lighting, it is a bit hard to see, but the piece on the left if floating and the piece on the right is at the bottom of the tub.

Next, we give each child a small square of foil and have them build a small boat.  Then they can load the boat with one penny at a time until it sinks.  They can then see how well each others boats did with loading.  This is a fun experiment that the kids really love.

The next experiment addresses capillary action of the paper towel, and adhesion of the water to the paper towel.  It is a tough concept to explain to kindergartners, so mainly we show them that the paper can pull up some of the water.  It is just a fun project.  The first photo below shows the paper towel with just a dot of food coloring on it, and the second photo shows the paper towel after it has been dipped and held in just a 1/2 inch of water allowing it to spread the color up the paper towel.

Another fun experiment that we do is to address density.  This topic relates back to the idea of sink and float.  If an object is denser than water it floats, less dense it sinks.  In this experiment, we have a glass of water and a glass of alcohol side by side.  We ask the students if ice floats or sinks.  They will answer float and we will drop and ice cube in each glass.  Surprisingly for the students, the ice cube floats in the alcohol.  They will be shocked.  Now ask them what happened.  Teach them how to gently smell the contents of the glass by waving their hand over the glass toward their nose.  They should recognize the smell of the alcohol from the doctor's office.  Explain how ice is more dense than alcohol.  Next, they can use a water dropper to add water to the alcohol jar to let the ice cube rise and the density of the liquid changes with the addition of water.

These are all fun.  We do one more experiment, but because I did not have an assistant today I could not photograph it.  In the last station, we have a tub, a large cup of water and a string.  I ask the students what happens if I pour the water out of the cup, where does it go?  Then I take a wet string and run it from the cup to the tub and pour out the water again.  This time, the water follows the string.  Next, have the students pick out a string and then pour the water.  The string they pick out will be dry and of course the water will not flow down the string.  They will be surprised it doesn't work.  Then wet the string and show them how the water molecules attract each other through cohesion, which is why this experiment works!

Hopefully, I will be able to take some photos of the kids performing some of these experiments.  I am just usually too busy working with the kids to take photos.

No comments:

Post a Comment