Physical and Chemical Changes

A physical change is a change in size, shape or appearance but not in substance.  Some examples we witnessed were: ripping paper, flattening a ball of Play-doh, and a melting ice cube.  Above we are drawing a balloon before and after it is blown up.

We agreed that making chocolates from chocolate wafers was a physical change.  

We melted the wafers and poured it into candy molds with Halloween sprinkles.

Then we chilled the chocolate until it was hard.  The substance didn't change but the shape did- a physical change.

We broke pretzels to show physical change then...

crushed them and added milk to make a paste.  Since we mixed two or more substances to make a new substance, it was a chemical change.  We also examined burnt matches as an example of a chemical change. 

Floating Marshmallows and Paper Test

We used our knowledge of density to try making marshmallows sink in water instead of floating.

This student took two tries to get one to sink. 

The students tried different things: breaking the marshmallow apart, flattening it, and squishing it into a small ball. 

Today our other quest was to find out which foods had the most fat in them.  Each child selected a food and then mashed it between two sheets of paper.

The foods that turned the paper translucent had the most fat in them.  This is the butter test. 

We were not surprised that peanut butter had a lot of fat. 

Most of the students predicted that the sugar had a lot of fat but the paper test showed us that it didn't.

We also had time to listen to an article about edible insects.  Even after learning that more than 2 billion people in the world eat insects on a regular basis, most said that they would not try them.  Google edible insects to view some interesting snack ideas. :-)

Floating Marshmallows and Paper Test

We used our knowledge of density to try making marshmallows sink in water instead of floating.

This student took two tries to get one to sink. 

The students tried different things: breaking the marshmallow apart, flattening it, and squishing it into a small ball. 

Today our other quest was to find out which foods had the most fat in them.  Each child selected a food and then mashed it between two sheets of paper.

The foods that turned the paper translucent had the most fat in them.  This is the butter test. 

We were not surprised that peanut butter had a lot of fat. 

Most of the students predicted that the sugar had a lot of fat but the paper test showed us that it didn't.

We also had time to listen to an article about edible insects.  Even after learning that more than 2 billion people in the world eat insects on a regular basis, most said that they would not try them.  Google edible insects to view some interesting snack ideas. :-)

Today we learned what dehydrating means and why it was used to preserve food in the past.

We used a crank apple corer/slicer to prepare apples for dehydration. 

The apples were spread on a tray on the food dehydrator. 

It takes about 15 hours until the fruit is ready to eat so I had strawberries, apples, and banana chips that I had already dried for the students to try.  We compared the fresh apples to the dried ones and about half of the group preferred the dried apples.

I also purchased some dried vegetables but they were not a big hit. :-)

We had some time leftover so each child chose a Lego challenge card and used Legos to complete the challenge.

October is Lockport Blue month to support our local police force!  You can show your support by displaying blue lights at your home.  

In Kitchen Chem today we made pancakes to demonstrate the chemical reaction that takes place when baking powder is added to the batter.  The students noticed bubbles rising to the surface.  This told us that a gas was forming.

Everyone enjoyed eating our experiment!

Two thumbs up!

While eating our pancakes we watched a youtube video that showed us more fun experiments we could do in the kitchen. Click on link below to view it:
experiments for kids

The students wanted to test our theory that the baking powder caused the pancakes to puff up so we made one without it.  It was much flatter than the other ones.

Here is a regular pancake held sideways.

We tried the balloon/bottle experiment again with baking powder instead of yeast.  It didn't blow the balloon up quite as much as the yeast did but it does show that the baking powder produces gas.

We had time to try a second experiment that proved that smell and sight are two senses that are linked closely with our sense of taste.  Each student closed his/her eyes and held his/her nose while I placed a Jolly Rancher in each mouth.  The students then guessed what flavor candy it was.  Out of 12 students only 2 could guess the flavor!