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Adobe Bricks
Students can use adobe bricks to build various types of structures
and models.
- The students can make their own adobe bricks from loam and
straw.
- Mix about 4 cups of loam with small pieces of straw.
- Add enough
water to make a thick mud.
- Place the mud in hollow blocks, ice-cube trays,
or any cube-shaped containers.
- Place the cubes in a very warm place for
about 2 weeks.
- Remove the cubes from their containers.
Alum Solution
Alum
can be used to study crystal growth and to investigate the properties of
saturated and supersaturated solutions.
- Alum can be obtained from a
drugstore.
- To grow large alum crystals, the students need a saturated
solution of alum.
- To prepare this solution, place 250 mL (1 cup) of water in
a pan.
- Add 6 teaspoons of alum to the pan.
- Heat but do not boil the
solution.
- Remove the pan from the heat.
- Stir in 1 teaspoon of alum at a
time until no more will dissolve.
- When this solution cools, pour it into
small plastic jars. Have the students suspend their seed crystals in the jars.
Baking Soda Solution
Baking soda solution can be used to produce carbon dioxide
by addition of an acid.
- Place 1 L (1 quart) of water in a plastic jar. Stir
in baking soda one spoonful at a time until no more will dissolve.
- Pour off
the clear liquid. Store in dropper bottles.
Beet Juice Indicator
Beet juice is an indicator, a substance that changes color
as the pH of a solution changes. Beet juice is red in acidic solutions and blue
in basic solutions.
- Wash and slice a fresh beet. Place about four slices of
beet into a pan containing 1 cup of water.
- Heat until boiling and continue
heating for about 5 minutes.
- Remove the beet slices and allow the red liquid
to cool.
- Store in dropper bottles.
Bromothymol Blue (BTB)
Bromothymol blue is an indicator, a substance that changes
color as the pH of a solution changes. Bromothymol blue is yellow in acidic
solutions and blue in basic solutions.
- BTB can be prepared by mixing 0.1 g
(a pinch) of bromothymol blue powder in 10 mL of a 4% solution of sodium
hydroxide.
- Add 20 mL of alcohol and dilute to 1 L with distilled water.
- The solution should be deep blue.
- If it is green, add sodium hydroxide
solution drop by drop until the solution turns blue.
- Bromothymol blue can be
purchased from scientific supply houses.
CAUTION: Sodium hydroxide is corrosive;
the BTB solution should be prepared in a laboratory. BTB stains hands and
clothes. Have students wear goggles and follow safety precautions when using BTB
solution.
Bubble Solution
Bubbles can be used to investigate a variety of
phenomena, including motion, surface tension, and refraction of light.
- To prepare a bubble solution that yields giant, long-lasting bubbles, add 1 cup
liquid detergent and 2 1/2 teaspoons glycerin to 3 cups water.
- Stir this
mixture carefully so that an excessive amount of suds does not form.
CAUTION:
Have the students wear safety goggles when blowing soap bubbles.
Crystal Garden
The growth of crystals can be observed by making a crystal garden.
- Half fill
a clear plastic jar with hot water.
- Slowly add salt to the water and stir to
dissolve.
- Continue adding salt until no more will dissolve.
- Place 1
tablespoon of vinegar in the water.
- Place a piece of charcoal or small
porous stone in the jar.
- Beautiful crystals will soon start to form on the
charcoal or stone.
Daffy Dough
Daffy dough will fascinate the students with its
unusual properties. It is fun to make and examine.
- Each group of students
should stir 1/2 teaspoon of salt into 1/2 cup of liquid starch in a medium-sized
container.
- Add to this 1/4 cup of white glue.
- Stir for 5 minutes.
- As this material starts to coalesce, have the students knead it until it
forms a ball.
- Squeeze out the excess liquid.
- If the mixture does not
coalesce, add salt sparingly and continue to knead the dough.
Dough
Dough can be
used to prepare and study imprints.
- To prepare dough, combine 10 cups of
flour, 2 1/2 cups of salt, and 4 1/2 cups of water.
- Mix thoroughly and knead
to remove any lumps. Make six dough balls, wrap each in plastic, and store them
in an airtight container.
Gelatin
Gelatin is a colloid and can be used to
investigate the properties of this type of mixture. Gelatin can also be used to
simulate the ground movement that occurs in certain types of soil during an
earthquake.
- Prepare gelatin by mixing the powder with hot water.
- Stir until the powder dissolves. Pour the solution into a clear, plastic bowl and
place in a freezer overnight.
Goo
Goo is a mixture that can be used to
investigate the properties of matter in the liquid and solid states.
- To make
goo, put 1/2 cup of water into a cup and add 5 drops of food coloring.
- Sprinkle 2 packages of plain gelatin on the colored water. Let this sit for
one minute. Then stir the mixture for one minute to break up the lumps.
- Let
the mixture sit for three hours so that it gels slightly.
Hard Water
Hard water
is water that contains large amounts of dissolved minerals. It can be used to
investigate how dissolved minerals affect the taste of water and the cleansing
action of detergents.
- To prepare hard water, first crush four antacid
tablets that contain calcium carbonate as an ingredient.
- Be sure the tablets
are crushed to a powder. Then mix the powder with 200 mL of water.
Indophenol Blue Indicator
Indophenol blue is used to test for the presence of vitamin C,
changing from blue to colorless in the presence of the vitamin.
- Prepare this
vitamin C indicator by mixing 0.1 g of indophenol blue powder in 1 L (1 quart) of
distilled water.
CAUTION: Have the students wear safety goggles when using
indophenol blue.
Iodine Indicator
Iodine indicator is used to test for the
presence of starch. It turns blue-black when starch is present.
- Iodine
indicator can be purchased from scientific supply houses as Lugol's solution.
- Lugol's solution can be prepared by dissolving 10 g of potassium iodide in
100 mL of distilled water.
- Then add 5 g of iodine crystals and mix. (Use
caution handling these chemicals; the solution should be prepared in a
laboratory.)
- Store the solution in brown dropper bottles. Tincture of iodine
obtained from a drugstore may also be used as an indicator.
CAUTION: Iodine
stains hands and clothes and is toxic. Have students wear goggles and follow
safety precautions when using iodine indicator.
Iron Filings
Iron filings can be
used to investigate chemical change (rusting), including the observation that a
component in air (oxygen) is involved in the process.
- Iron filings can be
made from a dry, fine-grade (grade 0000) steel wool pad, the kind without soap.
- Put on gloves.
- Pull the steel wool pad into two halves, hold them over
a piece of paper, and rub them together so that the iron filings fall onto the
paper.
- Carefully pour the iron filings into a dry jar.
- Cover until
ready to use.
Lime Water
Lime water is used to detect the presence of carbon
dioxide, becoming milky-cloudy when carbon dioxide dissolves in it.
- Add
about 3 g of calcium hydroxide to 1 L (1 quart) of warm water in a plastic
bottle.
- Cover and shake well. Let the solution cool.
- Pour off the clear
liquid.
- Store in a plastic bottle until ready to use.
CAUTION Have the
students wear safety goggles when using lime water. Do not ingest limewater.
Modeling Dough
Modeling dough can be used by students to make small models and
structures. It can also be used to investigate the properties of matter.
- To
prepare modeling dough, mix 1 1/2 cups of salt, 3 cups of flour, and 2
tablespoons of cream of tartar in a large bowl.
- Add 1/4 cup of vegetable
oil. Mix a few drops of food coloring in 2 3/4 cups of boiling water and add this
to the mixture.
- Mix until the color is uniform.
- Store dough in an
airtight container.
Ocean Water
Artificial ocean water can be used to investigate
the physical and chemical properties of sea water.
- To prepare artificial
ocean water, dissolve 300 g of table salt, 42 g of magnesium chloride, 28 g of
magnesium sulfate (Epsom salts), and 14 g of plaster of Paris in 11 L of water.
Phenolphthalein Indicator
Phenolphthalein is an indicator, a substance that
changes color as the pH of a solution changes. Phenolphthalein is purple in very
basic solutions and colorless in slightly basic and in acidic solutions.
- Ask
a pharmacist at a drug store for a package of any laxative that contains
phenolphthalein.
- Use the back of a spoon to mash four tablets on a saucer.
- Pour this powder into a small cup, add about 10 mL of rubbing alcohol.
- Let this mixture soak for about 15 minutes.
- Pour off the liquid and
store in a dropper bottle.
Polymer
Students can investigate polymerization and
the properties of a polymer with an example they prepare themselves. Prepare the
following solutions ahead of time.
- Solution A: Place about 1 L (1 quart) of
water in a pan.
- Slowly sprinkle 40 g of poly (vinyl) alcohol on the water,
while stirring.
- Heat this mixture (on a hot plate) to about 90°C.
- Do not boil it.
- Stir this mixture for about 20 minutes until it looks like
white corn syrup.
- Cool and store in a plastic jar.
- Solution B: Dissolve
8 g of borax in about 200 mL of water.
- Stir until dissolved.
- Store in a
plastic jar.
- To prepare the polymer, have the students place 30 mL of
solution A in a paper cup.
- Add to this 10 mL of solution B.
- Stir with
an ice-cream stick until a soft ball is formed.
- Remove the polymer ball from
the cup and knead for about 5 minutes.
Red Cabbage Juice Indicator
Red cabbage
juice is an indicator, a substance that changes color as the pH of a solution
changes. Red cabbage juice is red in acidic solutions and green or blue in basic
solutions.
- To prepare red cabbage juice indicator, tear about five leaves of
red cabbage into small pieces.
- Place these in a large beaker or a stainless
steel pot.
- Add 1 L of water, bring to a boil, and simmer until the water
turns a deep purple.
- Pour the liquid through a strainer or through a piece
of cheesecloth into a storage bottle. Keep the solution refrigerated.
Salt/Sand/Iron-Filings Mixture
A salt/sand/iron-filings mixture can be used to
investigate the nature of mixtures and to allow students to experiment with
methods of separating a mixture.
- Add the following materials to a large
plastic jar with lid: 1 cup kosher salt, 1 cup sand, and 1/4 cup iron filings.
- Shake to mix well.
- Each group of students will require about 1/4 cup of
this mixture.
Salt Solution
Salt solution can be used to investigate the
properties of solutions, including means of separating the components.
- To
prepare a 2% salt solution, dissolve 2 g of table salt (sodium chloride) in 98 mL
of water (preferably distilled).
Simulated Solid Waste Bag
Simulated solid waste
is useful for having students determine the kinds of materials that are disposed
of by people, and for investigating recycling possibilities.
- Gather a
collection of items representative of the materials typically found in solid
waste.
- You could include the following: toothpicks, plastic pieces cut from
canned soda cartons, paper clips, metal soda tabs, paper, cardboard pieces, glass
dropper, metal and plastic jar lids, and rubber bands.
- Each group of students will require one bag of solid waste.
Super Starch
Students can
investigate the unusual physical properties of Super Starch.
- The following
recipe makes enough Super Starch for six groups of students.
- Mix 4 boxes of
cornstarch with 6 3/4 cups of water. Add 15 drops of food coloring if desired.
- Store in an airtight container until ready to use.
- For easy clean up,
let the material dry and wipe up with a moist cloth.
Yeast Culture
Yeast culture
can be used to observe reproduction by budding. Yeast culture can also be used to
investigate fermentation and production of carbon dioxide.
- Prepare yeast
culture using a packet of dried yeast and following the directions on the label.
or
- Add about 25 mL of molasses or grape juice to 450 mL of water.
- Then
add 1/2 package of dried yeast to the mixture and mix.
- Set aside in a warm
place.
- The culture will be ready to use the following day.
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