LET'S MAKE CLOUDS

MATERIALS

Glass jar with lid
Ice cubes
Hot water
Flashlight

PROCEDURE

1. Fill jar half-full with hot water*
(*have an adult do this)
2. Place lid upside down on top of jar
Wait a few minutes
3. Now place ice cubes on the lid
Observe. May darken room and shine flashlight
through jar for better viewing

EXPLANATION

You should see moisture condensing on
the sides of the jar, resembling clouds.
When the air is cooled by the ice cubes, the
water condenses and drops back down into
the water.
This is similar to water vapor cooling
in the air high above us, condensing into
clouds of raindrops, and dropping back down
to earth as precipitation.

COLORS AND LIGHT

BEAMING COLORS

MATERIALS

Flashlight
Different colors of balloons, or colored cellophane
Scissors
Rubber band
Dark room

PROCEDURE

1. Cut balloon (or cellophane) and stretch it over the end of a flashlight, secure in place with rubber band
2. Turn on flashlight and beam the colored light to the ceiling, noting its color
3. Repeat steps 1 and 2 using different colors of balloons

EXPLANATION

The balloon works real well as a ‘filter.’ You can also do this with pieces of colored cellophane or plastic. White light consists of red, orange, yellow, green, blue, and violet colors. The ‘filter’ absorbs all those colors except for the one it transmits; for instance, a green balloon is absorbing red, orange, yellow, blue and violet, and transmitting green.

The 8 to 10-year-old probably will not understand the term ‘transmits.’ Use ‘beams’ or ‘sends out’ instead. If the child can picture beaming colors of light out of the flashlight using a filter, this will prepare them for learning the concept of white light consisting of multiple colors, some absorbed and one transmitted, when they are older. Prisms can be used to separate white light when they are older.

BUOYANCY

MATERIALS

Modeling clay
Dishpan
Water

PROCEDURE

1. Take a piece of modeling clay and split it into 2 identically sized pieces
2. Take one of the pieces and roll it into a ball
3. Take the other piece and smooth it out into a flat piece, like a little pancake
4. Fill dishpan with water
5. Ask child, “Do you think these pieces of clay will sink or float?”
6. Place both pieces of clay into tub of water at the same time. Observe.
7. Have child communicate observations.

EXPLANATION

If the total area of the object that makes contact with the water is large enough, the object floats. The object must make room for its own volume by pushing aside, or “displacing” an equal amount of liquid. The object is exerting a downward force on the water, and the water is exerting an upward force of the object. The solid body floats when it has displaced just enough water to equal its own weight. This is “buoyancy.” An object immersed in a liquid is buoyed upward by a force equal to the weight of the liquid displaced by that object (Archimedes’ principle.)