Some Science Ideas for Rainbows

Give each person/team an ice cube, a piece of string and some salt...
Ask each team to pick the ice cube up using the string.
What you do is sprinkle salt between the ice and the string and they react together letting you pick up the ice cube!

You need a shallow dish of milk, -drop in a couple of drops each of perhaps 3 different food colourings, in different areas of the milk.
- very carefully add one or two drops of washing up liquid at the
side of the dish.
- watch 'the show' over the next few minutes!

It's fantastic watching how the colours move and mix.

Over to the scientists to explain what is happening though!

If I remember correctly, the dishwashing liquid helps break up the water's "skin" (all the water molecules holding hands) and sends the molecules scooting all over the place. An activity we do to help the girls see how water molecules like to stick together is to see how many drops of water you can get on a penny (US penny = about 3/4 inch across - 2cm?) If you don't have a pipette or eye dropper, you can use a drinking straw to add water drop by drop. It's surprising how big the bubble of water can get!

Cleaning dirty coins with brown sauce as an introduction to acids, or use Coca Cola, and put them off it for life ;-) . Or a similar one, changing red cabbage vinegar by adding salt.*

*But do be aware that one should never clean old coins this way. Old pennies etc. may have a value well above their face value and this will almost certainly be completely lost if the coin is cleaned in any way at all other than with plain water and a very, very soft cloth (do not rub!)

SCIENCE IN ACTION - Balloon Blowing

Try to blow up a balloon without using your own breath. This will take
several people working together.

You will need:

* 1/4 cup vinegar
* A small plastic bottle (with a neck over which you can place the mouth of the balloon.)
* 2 tablespoons of baking soda
* A small balloon

1. Pour the vinegar into the plastic bottle.
2. Stretch open the balloon mouth and carefully pour the baking soda
into the balloon.
3. Place the balloon mouth over the bottle. Make sure the balloon mouth is tightly around the neck of the soda bottle.
4. Hold the balloon to the side so that the baking soda does not fall into the bottle.
5. Shake the balloon so that the baking soda falls into the bottle,

What happened? Can you figure out why?

- Try-Its for Brownie Girl Scouts



Select at least 2 of the following areas of interest and do an applicable
activity - either the one listed here or another equivalent challenge.

Structures: Explore how to build a tower that is stable and will support

Materials for each team: 15-20 Gumdrops, 20-30 marshmallows (preferably the little ones), 40 toothpicks (round ones with 2 pointy ends).

Step 1) Divide the girls into teams of three.

Step 2) Each team should build a tower with the materials provided. The goal is to build the highest tower possible, without it tipping over.

Step 3) They can now dismantle the tower and eat the marshmallows and gumdrops!

Tips: They need to build a strong base before trying to build it high. Cross bracing (i.e. triangles with the toothpicks) help to reinforce the

When the tower starts to tip over, quickly place some toothpicks in the way that it is tipping to support the tower better. There is no wrong design!

Buoyancy: Explore the effect of boat design on its ability to hold weight.

Materials for each girl: piece of aluminum foil approximately 30 cm by roll width. Also, bring a large container, or several buckets, and lots of pennies (100 or so).

Step 1) Give each girl a piece of aluminum foil. Direct them to make a boat with it. Tell them you will be counting how many pennies it will hold without sinking.

Step 2) Fill the large container or buckets (or use the sink) about halfway full of water. Float a couple of boats at a time. Drop the pennies one by one into each boat (the girls can help count!).

Step 3) Discuss the designs with the girls. Can they see why some boats took on water very quickly (perhaps there was a hole, or a fold in the foil, at the water level)? Can they see why some boats held many pennies (perhaps the boats had large flat bottoms or higher sides)?

Tips: Let their imaginations guide them in their design because you want a variety of boat designs to illustrate why some boats hold the pennies and why some sink.

Flight: Make a paper helicopter called a spinner! It will spin faster as the girls add more weight.

Materials for each girl: piece of writing paper (9 cm X 12 cm), 6 paper clips, scissors, and pencil. (Click here for diagram.)

Step 1) Have an adult measure and cut the paper (along the lines) as shown. Label each spinner with a girl's name.

Step 2) The girls can fold the two outside flaps in opposite directions as shown. Then they should attach a paper clip.

Step 3) Have the girls stand on a chair, on a stage, or at the top of a stairwell, and drop their spinner.

Step 4) Retrieve the spinner, add another paper clip or two and try again. Continue until you've used about 6 clips, or the girls are losing interest!

Tips: The dimensions are important. Also, the higher the girls can drop it from the more impressive the spinning will be. A loft or stage is ideal.

Why: As the spinner falls, the air rushes out from under the flaps, or
wings, in all directions. Some of the air hits the edge of the body near the wing, causing it to rotate. As the weight increases, the spinner drops faster, and this increases the air movement around the wing, which causes the spinner to spin faster. Perhaps a little 'heavy' for 5 and 6 year olds, but they will enjoy the spinning!

Sound: Explore how to concentrate and amplify sounds using an ear trumpet.

Materials for each girl : large sheet of paper, tape, crayons. Also, bring a radio.

Step 1) If time permits, the girls can decorate their ear trumpets.

Step 2) With the help of an adult, roll the large sheet of paper into a cone shape and tape the ends. The small end of the cone should be large enough to fit over their ear (approximately 7 cm in diameter) so that they can't stick it into their ears!

Step 3) Once everyone is quiet, play a radio or stereo quietly. Ask the
girls to place their trumpet over one ear and aim the trumpet at the radio to see if the radio sounds louder.

Step 4) The girls can turn the trumpet around and try talking into the
narrow end to see how it amplifies their voice. Have them shout out their names all at the same time to see who is the loudest!

Why: The cone shape focuses, or concentrates, sound in one direction. For example, when you are shouting in the narrow end, it focuses the sound of your voice in the direction you are aiming the trumpet, which makes the sound louder and it carries further.

Challenge created by the Alberta Program Committee 2000


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