real science for today's homeschooler

Edible Cell Models

Edible Cell Models

When teaching about the parts of the cell, increase your child’s interest by having them build an edible model of a cell. The type of cell and the type of model depend on the age of the child and your snack preference for them.

If your child is older they can research “parts of a cell” online to find many different diagrams of different types of cells. Help your child find a diagram at an appropriate level for their age and understanding. If you have a younger child, you may want to select the diagram for them. Children should then decide which cell parts they want to include in their model. Encourage them to find out more about each part . . . what does it look like and what does it do for the cell?

Next, decide on what type of edible model you want your child to make. Two popular choices are cookies and pizzas, but any snack that provides a flat surface to “decorate” will work. Whichever snack you choose, prepare the “base” (cookie, pizza crust, etc.), and collect a variety of toppings your child can use to represent the cell parts. A wide variety of shapes and colors will allow for more creativity and interest.

Children should select a topping that best represents each part of the cell they have decided to include in their model. Help them decorate the snack base to accurately model a real cell. Relative size, shape, and number of cell parts should be considered. Do stress to your child that the diagram they are using is just another person’s model of a cell and they do not have to look exactly alike!

Challenge your child to tell you the name and function of each cell part in their edible model before they eat it! You may also want to take pictures of the model before it disappears.

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Making Rocks Fun!

Making Rocks Fun!

Okay, I have to admit, rocks sound boring to most people. But here’s a way to get kids interested in the topic of rocks and minerals!

Kids (and adults) love to find treasure. Purchase a bag of “mining rough” and you have a ready-made treasure hunt for your kids. Mining rough is the left over material generated by the mining process. To a mine that recovers and sells gemstones, it isn’t cost effective to spend time going through the left over material to pull out the small gemstones. They bag it “as is” and sell it at very reasonable prices. Going through the bag is literally a treasure hunt and you can find some very nice samples of amethyst, crystal quartz, and other gemstones including small samples of rubies and emeralds. Nothing that’s really worth much money, but pieces that will excite your kids!

There are many mines that sell this “mining rough,” but here’s a link to the one I order from: Cold River Mining Company. They do sell wholesale, but this link will take you to their “store” where you can buy individual bags. If you have a cave attraction nearby, you can probably purchase bags of mining rough there.

You’ll also need a sieve to separate the dirt from the larger rock and mineral specimens. You can purchase one from the mine, but it’s much cheaper to make your own. I would suggest getting a 1-foot x 1-foot piece of window screen to use as a sieve. The fiberglass screen works much better than the aluminum wire screen. The cut ends of the aluminum around the edges can puncture the skin!

The mining rough is dirt and rock straight out of the ground, so it can be messy. This is a great outdoor activity when the weather’s nice! Put the kids in their bathing suit or old clothes you don’t mind getting dirty and wet.

Here’s how to mine for gemstone treasure:

1. While your child holds the screen, add a small amount of mining rough to the center of the screen.
2. Spray the rough with a garden hose set on a low setting. The dirt will wash off revealing the rocks and minerals. (You can also dip the screen in a bucket of water, but the garden hose is much more fun!)
3. Collect the large pieces from the screen and let them dry.
4. The bags of mining rough usually come with an identification guide that kids can use to identify their gemstone treasures.

Be sure to explain to your budding geologists that gemstones are rocks and minerals that formed deep inside the Earth. Because the Earth is always moving and changing, sometimes these rocks and minerals get pushed up close enough to the surface for us to dig them up.

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Leaf Prints – Science meets Art!

Leaf Prints - Science meets Art!

Use an old standby in kids art projects to teach some plant science!

The Art

Remember making leaf prints when you were a kid? Here’s a short procedure:

1. Collect a variety of fresh, green leaves.

2. Provide a large sheet of clean paper. Thin paper works best. You’ll also need some old crayons with the paper peeled off.

3. Place a leaf under the paper. Use the side of the crayon to rub across the paper above the leaf. An impression of the leaf will appear. Encourage your child to push down hard enough to make the stem, veins, and outer edges visible.

4. Continue printing different leaves with different colors to create a collage of leaf prints!

The Science

Okay, so where does the science come in? Use the image below to help your child identify the parts of the leaves on their collage. They can label one or all of the leaves with the different parts.

leaf-parts Explain to your child that the veins in a plant are similar to the veins in an animal. They are used to transport materials throughout the organism. Plant veins are different from animal veins in that they carry water instead of blood.

You can also have your child identify the basic shape of different leaves by comparing the leaf prints to the diagram below:

leaf shapes 2

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How much would you weigh on different planets?

How much would you weigh on different planets?

What is weight?

Your weight would be very different if you lived on another planet. Assuming your size didn’t change, why would your weight change? To understand this, you have to know what the term “weight” really means.

A term that’s often confused with weight is “mass.” Mass is the amount of matter (stuff) that something is made of. Your mass wouldn’t change no matter what planet you happened to be standing on. But “weight” is not the same as mass.

Weight is a measure of the force with which gravity pulls down on your mass. So, if gravity changes, so does your weight! The gravity of a planet is determined by the size (mass) of the planet. Heavier planets exert more gravitational force than lighter planets.

 What would you weigh if you visited a different planet?

To calculate your weight on different planets, multiply your weight on Earth in pounds by the “gravitation factor” in the chart below. The Moon is also included.

Celestial

Body

Gravitation

Factor

Your

Weight

Mercury

0.38

Venus

0.91

Moon

0.17

Mars

0.38

Jupiter

2.54

Saturn

1.08

Uranus

0.91

Neptune

1.19

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How old are you on a different planet?

How old are you on a different planet?

What is a year?

We measure age in years. A year is a unit of time equal to the number of days it takes the planet to travel all the way around the Sun and return to its same location along its orbit.

Earth takes 365.25 days to make a trip around the sun, so our calendar year is usually 365 days. Once every four years, one day is added to the calendar at the end of February to account for the 0.25 day each year. That’s why we have a “leap year” every four years.

If you lived on another planet, a year would not be 365 days because each planet takes a different amount of time to make a trip around the Sun, based mainly on its distance from the Sun. (The farther away from the Sun, the larger the orbit and the longer it takes to go around the Sun.) Assuming you still referred to a “year” as one trip around the Sun, your age in years would be very different from what it is on Earth.

 How many years old would you be on different planets?

To calculate your age on different planets, first, divide your age by 365.25. Then multiply that answer by the number of days in the “year” of each planet. You can find that information in the table below:

Planet

Days in Year

Your Age

Mercury

87.97

Venus

224.70

Mars

686.67

Jupiter

4331.87

Saturn

10760.27

Uranus

30604.65

Neptune

60189.48

 

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Separating Colors with Chromatography

Separating Colors with Chromatography

What is Chromatography?

Chromatography is the process of separating a mixture into its individual components. The easiest way to show this process to children is by using chromatography to separate inks. Waterproof inks in permanent markers and ball point pens require a chemical solvent, but the ink in washable markers can be separated with water, making for an easy and safe experiment.

Materials:

washable markers, coffee filters, pie pan

Procedure:

1. Flatten a coffee filter so that it can be written on.

2. Using washable markers, put small dots of different colors around the outside of the filter, about ½ to 1 inch from the outside edge. (Smaller dots work best. It is hard for the colors to really separate if there is too much ink on the paper.)

3. Put water in the bottom of the pie pan, using just enough to cover the bottom completely.

4. Arrange the filter so that it is back in its original shape with the pleats all neat, etc.

5 Place the filter upside down into the pie plate so that the outer edges are in the water. (It is very important that the dots be above the surface of the water in the pan. If the dots touch the water, the ink will dissolve into the water and the chromatography won’t work!)

6. Allow the water to creep up through the filter. As the water reaches the dots, the ink will begin to spread out and separate. This will take some time, but eventually the water will reach the top.

7. When the filter is completely wet, carefully remove the filter and allow it to dry.

8. Examine the results to see which colors make up each of the inks tested.

How it works:

The process of using paper chromatography to separate inks is pretty simple. Most colors of inks are actually made of more than one pigment, or color. Each of those pigments has different properties. Some are heavier than others. When a solvent passes through the ink, it picks up the different pigments and begins to carry them along. The lighter the weight of the pigment, the faster and farther it will travel. As each pigment continues to travel at a different speed, they become separated from each other, allowing you to see the individual colors that make up the original ink.

 

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Popsicle Science – Turn a Summer Snack into a Science Lesson!

Popsicle Science - Turn a Summer Snack into a Science Lesson!

Do you make popsicles for your kids during the summer? Involve them in the process and turn it into a science lesson!

Materials:

juice, plastic cup, ruler, waterproof marker, popsicle stick (or plastic spoon), index card

Procedure:

1. Fill a small plastic cup about ½ full of juice. (Cups with the straightest sides work best.)

2. Cut a slit in the middle of an index card and place it over the cup. Insert a Popsicle stick or plastic spoon through the card and into the liquid, holding it upright with the index card.

3. Make a mark on the outside of the plastic cup at the top of the juice.

4. Measure the height from the bottom of the cup to the mark. Record.

5. Place the cup in the freezer and leave undisturbed until frozen.

6. Remove from the freezer and measure the height of the frozen juice. Record.

7. If age appropriate, calculate the change in height and record.

8. Ask the question, “Why is there more juice in the cup when it is frozen?”

How it works:

Juice contains a large amount of water. Water is one of the only substances on earth that expands when it freezes. Most liquids contract as they get colder as the molecules slow down and get closer together. Water does contract as it cools all the way down to 4°C. But between 4°C and 0°C (the freezing point of water), the water molecules actually begin to spread farther and farther apart. Solid water (ice) is less dense than liquid water because the molecules in ice are spread farther apart than in water. That’s why ice floats in water.

 

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