Plant and Animal Cells

This is a fun activity where students will create two cells:one animal cell and one plant cell. They will then compare and contrast the two.

MATERIALS

2 Plastic see-through sandwich sacks with twist-ties per student
1 Square hard-plastic sandwich container per student
Lemon gelatin
Various fruits and vegetables such as:
Raisins, plums,small carrots, mandarin oranges, red grapes, cherries, celery
Boiling water, ice cubes, large bowl, spoon, measuring cup

PROCEDURE

1. Boil water and make the gelatin, using ice cubes instead of cold water
for quick cooling. While gelatin is cooling, go to step 2.
2. Have students list the organelles of the cell that they've studied.
3. Have students choose the fruits or vegetables they want to represent
the organelles of the two cells. Ex: raisins for ribosomes, plums for the
two nuclei (one plant, one animal), orange slices for mitochondria, cut
celery for chloroplasts, etc.
The two sacks will represent the plant cell membrane and the animal cell membrane.
The sandwich container will represent the plant cell wall.
4. When gelatin has cooled but not completely set, transfer some gelatin
into each of the two plastic sacks. This represents the cytoplasm in both cells.
5. Have students place their "organelles" into the appropriate cell. When
done, twist-tie the sacks.

EXPLANATION

Students will observe that the plant cell has a cell wall (the sandwich
container) along with a cell membrane (the plastic sack)and chloroplasts. The animal cell has the same organelles, minus the chloroplasts and also the cell wall.

Does Air Weigh Anything?

This easy activity answers the question, "Does air weigh anything?" You may be surprised at the answer!

MATERIALS

2 Balloons of equal size
Balance
(NOTE: If you don't own a balance, the child can make his/her own. Take a ruler that has 3 holes in it. Put one paper clip in each of the 3 holes. Hang the ruler/balance by the middle paper clip on a rod.)

PROCEDURE
1. Ask the child, “Do you think air has mass (weight)?
2. Hang one balloon on one end of the ruler balance by attaching to the paper clip.
3. Blow up the second balloon.
4. Attach the second balloon to the other end of the ruler balance.
5. Compare weights.

EXPLANATION
The fact that air has mass (weight) is an important concept for children to grasp. Air is matter. Matter must satisfy two conditions: it must take up space, and it must have mass (weight). This activity vividly shows that yes, air has mass, because the balloon which was blown up will pull its end of the ruler down. When they are older, they will learn how to calculate, using a periodic table, the mass of different gases. It’s easy!

TRANSPIRATION

This activity is very easy. Plants release water in sunlight to cool themselves. This process is called Transpiration.

MATERIALS

A sunny day
An outdoor plant/tree with lots of green leaves
A plastic grocery bag (not the ziplock type), preferably see-through, with twist-tie

PROCEDURE

1. Place a plastic bag over the end of a plant/tree branch with green leaves in bright sunlight.
2. Twist the tie around the base of the bag to keep out air.
3. You can do this to various trees/plants to compare.
4. Predict what will happen.
5. Wait one to two hours.
6. Remove the bag. Observe.

EXPLANATION

Stomata, which are tiny openings in a leaf, allow gases to enter and leave the plant. They take in carbon dioxide from the air that we breathe out, and use it to make food. They also release oxygen and water. This evaporation of water is called Transpiration. You should see droplets of water inside the plastic bag.

DOES GAS TAKE UP SPACE???

MATERIALS

Balloon
Paper towel
Drinking glass
Sink of water
Optional: Styrofoam peanut

PROCEDURE

1. Have child blow up a balloon. Ask, “What is inside this balloon?” (carbon dioxide gas molecules.) “Does the gas take up space?” (yes) “Why can’t you see the gas?” “Where does the gas go when the balloon pops?”
2. Now, stuff a paper towel into the bottom of a drinking glass so that it will not fall out when the glass is inverted.
3. Fill your kitchen sink full of water.
4. Ask, “Do you think this paper towel will get wet if we plunge this glass upside down into the sink of water?”
5. Hold the glass upside down and quickly plunge it into the water.
6. Count to ten while holding the glass underwater.
7. SLOWLY lift the glass up and out of the water. Be sure to hold the glass straight up and down.
8. Observe. What happened to the paper towel?
9. May also do this with a piece of Styrofoam. Place the Styrofoam in the water. Place your glass upside down over the Styrofoam and push straight down into the water. What happened?

EXPLANATION

Air (gas) molecules take up space. Therefore, water could not get into the glass. The paper towel, and the Styrofoam peanut, remained dry.

FRICTION THROUGH WATER

MATERIALS

Wide-mouthed see-through jar, or empty tennis ball can
Clay
Water

PROCEDURE

1. Add water to your container until it is almost full.
2. Take a small amount of clay and roll it into two small balls.
3. Take one of the balls and flatten it like a small pancake. Leave the other piece round and smooth.
4. Hold both pieces of clay just above the surface of the water. Ask, “Which piece of clay do you think will drop the fastest?”
5. Now drop both pieces of clay through the water at the same time. Observe. Discuss. What role did friction play with the different speeds of the clay?


EXPLANATION

Friction is the resistance of motion on the surface of a body. The more surface, the more friction, the more resistance to motion. Fish and boats are streamlined to reduce their surface so they can speed through water more easily.

ACID INDICATOR

MATERIALS

Bromthymol blue (BTB) (available in supply catalogs)
A cup (a glass, or even a test tube)
Drinking straw

PROCEDURE

1. Add 1-2 drops BTB to 15 ml of water.
2. Using the straw, blow into the BTB solution.
3. Observe.

EXPLANATION

BTB is an indicator for acid. Carbon dioxide, when mixed with water, forms a weak acid. When acid is present, the blue BTB will turn yellow. When you blow out, you are blowing out carbon dioxide. You should see the solution turn yellow.
BTB is inexpensive and easily obtained in supply catalogs. You will find that you will use it for more than one experiment.

SAFETY PRECAUTIONS

BTB is a stain and will stain clothing. Always have an adult present and remind children not to put any solutions into their mouths.

LET'S MAKE FOSSILS

MATERIALS

1/2 cup cornstarch
1 cup baking soda
5/8 cup cold water
wax paper
leafs, bones, shells

PROCEDURE

Have an adult stir first 3
ingredients over medium heat.
Shape into about a dozen one inch balls.
Flatten a ball onto wax paper.
Press a leaf, bone, or shell into the dough.
Remove the leaf, bone or shell, leaving
an imprint.
Allow to dry.

EXPLANATION

Fossils are found in sedimentary rocks.
Prerequisites for fossils are:
1) organisms must be hard, such as bones,
teeth, shells
2) they must be in an oxygen-free environment,
away from predators
3) they must be in favorable heat and pressure
conditions

Four types of fossils:
1. Petrified fossils
Examples are porous wood or bones. Minerals seep
in, turning the porous material into stone.
2. Carbon fossils
Water and gas are squeezed out of the material,
leaving only carbon.
3. Molds and casts
The material leaves a hole in the rock in the
exact shape of the original specimen.
4. Trace fossils
Signs are left behind by an organism.
Examples: footprints, nests, burrows

GOOEY STUFF

MATERIALS

Half of a box of cornstarch (227grams)
200 ml water (7/8 cup)
Few drops food coloring
Container with airtight lid
Metal spoon

This mixture should stay fresh for about two weeks if stored in refrigerator in an airtight container.

SAFETY PRECAUTIONS
Always remind your children not to taste anything during a science experiment.

PROCEDURE

1. Mix the cornstarch and water together until texture is smooth. Add green food coloring. Have child dig into it with their hands, feeling the texture and observing the characteristics of this weird mixture.
2. Have your child describe to you the characteristics and make a list of them. They may notice it is both “runny” and “powdery” at the same time. How can that be? Encourage description and discussion.
3. Ask: What do you think will happen if you strike the “gooey stuff” with a metal spoon?


Always have the child predict what will happen, then actually do it, then discuss what they observed actually happened.


EXPLANATION

The liquid particles of the water are scattered throughout the solid particles of the cornstarch. The particles of one are dispersed throughout the other. Therefore, each substance, the liquid and the solid, retains its own individual characteristics (properties.) Hence, this “gooey stuff” has the properties of a liquid and a solid simultaneously- runny and powdery at the same time. Weird!

MAGNETIC MUSCLE

MATERIALS

Scissors
Ruler
String
One Bar magnet
Masking tape
Box of about 100 small paper clips
Large bowl

PROCEDURE

1. Cut 2 pieces of string, each about 1 meter long.
2. Tie one end of each string to each end of the bar magnet.
3. Tape the free ends of the strings to the top of a doorframe. Adjust height as necessary.
4. Ask, “Which part of the magnet do you think will attract paper clips the strongest?” Then, raise bowl full of paper clips so that the magnet touches the paper clips.
5. Slowly lower the bowl.
6. Observe what part of the magnet attracts the most clips.

EXPLANATION

Most of the clinging paper clips should be concentrated at or near the 2 ends of the magnet. All magnets are surrounded by an area called a magnetic field. This force moves from the north pole of the magnet, around the side, and into the south pole of the magnet. These magnetic force lines are closest together at the 2 poles, which give the 2 poles the strongest magnetic attraction.

SOUND WAVES

This activity is easy to set up, and gives the student a visual about how sound waves move.

MATERIALS

5 marbles
Flat surface

PROCEDURE

1. Line 4 marbles up in a straight line on a flat surface, close enough that they are touching each other.
2. Shoot the 5th marble so that it hits the end marble.
3. Observe. Discuss.

EXPLANATION

Each marble contains a certain amount of energy called Potential Energy. When the 1st marble hits the second marble, the Potential Energy is converted to Kinetic Energy (energy of movement) and passes its energy on down the line to the third marble, and so forth. This passing of energy from one marble to the next illustrates the way a sound wave is produced.

A THREAD OF CRYSTALS

This activity takes a few days, up to a week, after the setup to grow the crystals. The result is a variety of beautiful crystals for students to observe and compare.

MATERIALS

Gather as many of the following substances as you can: Epsom salt, Alum (found in the spice section at the grocery store), Borax (found in the laundry section in your grocery store), Rock salt
Hot water
A glass jar for each type of crystal grown
Cotton thread
A pencil for each type of crystal grown (or Popsicle stick)
Adult

SAFETY PRECAUTION
Use appropriate safety precautions when using hot water. Have an adult present for use with hot water.

PROCEDURE

1.With an adult, heat water on stovetop. Pour into glass jar.
2.Add your substance (Alum, Borax, Epsom salt, or Rock salt) to the hot water until you cannot stir in any more substance. This is a saturated solution.
3.Pour the above solution off into a clean jar. Leave behind any undissolved salt.
4.Tie a thread to a pencil (or Popsicle stick) and suspend the thread into your solution. Bridge the opening of the jar with the pencil.
5.Label your jar as to the type of solution.
6.Cover the jar with a piece of paper towel to control the rate of evaporation. Set aside in a place where it will not be disturbed.
7.Repeat above procedure with each substance. You should have 4 jars, one for each type of substance used. Label each.
8.Observe daily. Record your observations. Draw what you see.

EXPLANATION

As the water evaporates, the substance will come out of solution and begin to grow on the thread. This process can take days, even a week. Each crystal will look different. All 4 of these substances are a type of salt: Alum salt, Borax salt, Epsom salt, and Rock salt. As the liquid cools and the water evaporates, some of the molecules in the substance move closer together and join in a repeating pattern. The crystal grows in size by adding more molecules in the same pattern. Each type of crystal has a unique pattern.

CHEMICAL REACTION

This is a fun and easy activity to do that involves
a chemical reaction. Your students will clean for
you, and they won't even complain!

MATERIALS

Tarnished pennies
Vinegar
Salt
Small bowl or jar

SAFETY PRECAUTION

Appropriate safety precautions to protect eyes while working with
vinegar should be used.

PROCEDURE

1. Place about ¼ cup (about 60 ml) vinegar into small bowl or jar.
2. Add about 2T (30ml) salt. Stir.
3. Add several tarnished pennies to the bowl. Leave one tarnished
penny aside to use for comparison.
4. Wait a few minutes. Ask, “What do you think will happen? Why?”
5. After a few minutes, remove the pennies.
6. Experiment with different amounts of vinegar and salt. Which
works best?

EXPLANATION

A chemical reaction occurred. Salt is sodium chloride. The chloride
from the salt combined with the hydrogen from the vinegar to form
hydrochloric acid, which cleaned the pennies.
You can use this formula to clean any copper or bronze object in your
home, or use especially formulated brass cleaner.

LET'S MAKE A HYGROMETER

When studying the weather, an easy science activity to do is make a hygrometer, which measures the humidity. This activity is best for homeschoolers because it requires an oven. The activity works great and is easy to do.

MATERIALS

Pine cones
Aluminum foil
Oven
Water
Bowl
Cake pan

PROCEDURE

1. Place pine cones in water in the bowl.
2. Wait 45 minutes. Then draw a picture in
your science journal of the pine cones,
observing their scales.
3. Transfer pinecones to cake pan which you
have lined with foil for protection.
4. With an adult, bake the cones on low heat
in the oven for 30 minutes.
5. Remove pan from oven. Now draw a picture
of the scales in your science journal. Label.

EXPLANATION

A hygrometer measures the humidity (moisture in
the air.) A pine cone makes a good hygrometer.
When the pinecones are wet, the scales close
up. When they are dry, they open.

pH INDICATOR

MATERIALS

Red cabbage
Sugar water
Baking soda
Vinegar
Cups (clear plastic, or paper)
Knife and pan
Stovetop

SAFETY PRECAUTIONS

Should be supervised by an adult due to the chopping with a knife and heating on a stovetop.

PROCEDURE

1. Chop a few leaves of red cabbage finely and place in pot. Cover with water, bring to boil, reduce heat, and simmer until solution is deep blue/purple.
2. Allow cabbage solution to cool. Strain into a jar. After the experiment is over, be sure to save this solution for other experiments. It saves well, covered, in the refrigerator. This is your indicator. If you wish, you may also take strips of white filter paper (such as a coffee filter cut into strips 2-3 inches long) and soak in the juice, and then let dry, to use as indicator strips to experiment with. Still save the juice, however.
3. Explain the term ‘indicator.’ (a substance that indicates if something is acidic or basic.)
4. Mix baking soda with a little water in a cup to make a baking soda/water solution. Label “baking soda”.
5. Pour a small amount of sugar water into another cup and label “sugar water”.
5. Pour a small amount of vinegar into a third cup and dilute with a little water. Label “vinegar”.
6. Ask, “What do you think will happen if we pour our cabbage juice/indicator into these cups?”
7. Add cabbage juice/indicator into each of the 3 cups, recording observations on the chart provided.
8. Discuss acids and bases and how they react with the cabbage juice indicator. Discuss neutral solutions and how they react with the indicator.

EXPLANATION

Cabbage juice is an indicator that indicates if a substance is acid, base, or neutral. If a substance is an acid, the cabbage juice (or strip) will turn pink or red. If a substance is a base, the cabbage juice will turn green or blue-green. If a substance is neutral, the cabbage juice/indicator will not change color. The vinegar is an acid and will turn pink. The baking soda is a base and will turn green.