Kids' experiments about things at home

(Last of 2-part Series)

(Editors note: On Saturday, Oct. 21, the 2006 Chemistry Exposition will be held at the St. Louis Science Center. The theme is: "Your Home: It's all built on chemistry." This article gives specifications for four home-product experiments kids can do at home.

(Also, to meet some of the SIUE chemistry students who will be on hand at the exposition to help kids, see sidebar below.)

When kids think about building a home during the frontier days, they probably think about log cabins or deer-skin teepees. Just chop down trees or skin some deer.

But, what about the materials used to build homes in the 21st century?

Scientists at the 2006 Chemistry Exposition at the Science Center will show you that today's building materials rely a lot on chemical reactions. In this article, Young Saint Louis.com will outline experiments you can do to test or make products for the home.

The experiments will let you check the insulation values of various materials and make homemade bricks from salt and flour. Also, you'll make house paint with common household products.

Another experiment will show how several thin strips can be stronger than one thick one.

One warning: The American Chemical Society urges kids to do all of these experiments with a parent or another adult in attendance.

Milli's Insulation Investigation

People like to have their homes cooler inside when the summer heat comes. They also like their homes warmer when winter's storms come.

But, most people understand that to make these conditions happen takes more than a fire or an air-conditioner. It takes insulation. But, what type of insulation works best?

These experiments test insulating values of several substances. You can think of others.

For this experience, we'll use aluminum foil, newspaper, plastic wrap and waxed paper.

Materials:

Procedure:

What Did You Observe?

Describe how the cube looks (if you can see it) or how big the damp circle on the paper towel has become.

Which cube melted the fastest?

Which cube took the longest time to melt?

List the wrappers in order from the worst to best insulation?

Why do you think some are better insulators than others?

Where's the Chemistry?

The wrapper that allowed more heat through to the ice and melted it fastest is the worst insulator. The wrapper that kept the heat away from the ice and melted it the slowest is the best insulator. Metal tends not to be a good insulator because it transfers, or conducts, heat. In this case, it conducted the heat from the warmer air in the room to the cold ice.

Avi's Sensational Salt Dough

Bricks are made by shaping clay and then drying or baking it at high temperatures. In this activity, you and your adult partner can mimic how bricks are made. You will shape and bake creations from a dough made from only flour, salt and water.

Materials:

Procedure:

What Did You Observe?

How did the dough feel as you started to shape it? After you baked it?

Where's the Chemistry?

In this activity, a chemical change occurred when you baked the dough. It was soft and elastic at first and then became hard and rigid during the baking. When a chemical change happens, things cannot be made to go back to what they were like originally and something new is formed. You can notice these changes by observing how it looks and how it feels. The color may be different, or it may feel solid instead of soft. In order for chemical changes to occur, heat made be required like in this activity.

Making Playtime Paint

Why do we paint our homes? We paint the outside of our homes mainly to protect them from the rain, wind and sun. Other reasons we paint are to make our homes and the rooms inside look nice and brighten our lives.

Modern paints are highly specialized and complex. But, they all have two basic parts: pigments and binders.

Pigment gives paint its color. The binder adds important chemicals that "hold" the pigment, help the paint stick to surfaces and allow it to form a smooth film when it dries.

In this experiment, you will make your own paint using chalk as a pigment and glue and water as binders.

Materials:

Procedure:

Where's the Chemistry?

Paint is made of tiny particles of color that are suspended in a liquid instead of dissolved in it. Think about what happens when you add salt or sugar to water. It dissolves into what is called a solution. Unlike a solution, paint particles "float" within a thick liquid such as oil or glue. The thick liquid helps the paint stick to and spread evenly across a surface. Then it allows it to form a film on the surface as it dries. In this activity, the glue and water mixture suspended the chalk's colored pigments. That is, the glue acted as a binder to help spread the paint evenly across a surface to dry.

Testing Spaghetti's Strength

Can you think of an example of a polymer that is a strong building material? Yes you can! Wood is a naturally occurring polymer found in the lumber used to build the frame of a home or in the plywood placed on the outside part of the frame.

One of the reasons it is strong is because of the strength of its chemical bonds. Chemical bonds can be broken by force. Scientists test how much force is required to break a material sample. That's to make sure the material is strong enough for building purpose.

As in plywood, greater strength can be achieved by bonding thin strips together.

In this activity, you will see how scientists examine building materials. But, in your case, you'll test the strength of spaghetti and how the number of strands effects its strength.

Materials:

Procedure:

What Did You Observe?

Which number of strands was the first to break? ___________ the last?___________

Which type of pasta held the most pennies overall?

Why do you think this is so?

Where's the Chemistry?

Spaghetti is a type of polymer called a carbohydrate. Its bonds are strong. However, it could only support a certain number of pennies. When there was too much strain on the spaghetti strands, it caused the chemical bonds to break. There is strength in having several strands of spaghetti stuck together. This allows more pennies to be supported.