real science for today's homeschooler

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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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