Posts Tagged ‘Science’

Monarch Season

August 5, 2009

met⋅a⋅mor⋅pho⋅sis

–noun, plural -ses 
  Biology. a profound change in form from one stage to the next in the life history of an organism, as from the caterpillar to the pupa and from the pupa to the adult butterfly
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There are few things more magical than watching a caterpillar turn into a chrysalis and then a butterfly.   This is a great time of year to find monarch caterpillars on milkweed!  Not only is it fascinating to observe metamorphosis, it is a great opportunity to have your child create some fantastic artwork.

Take your child to a park, or a farm, or even look in the weeds by your local gas station and search for some milkweed.  (See photo below.)  Look carefully on the plants, and there’s a good chance you’ll find a Monarch caterpillar like the one my daughter is watching at in the photo at the top of this page.  Carefully take the caterpillar and plenty of milkweed with you and put them in a large see-through container.  We used an old plastic pretzel container, but a large jar or Tupperware container would work too.   Just make sure you punch air holes!  I put the milkweed in a little vase with water to keep it alive, but a friend told me you can put the leaves between damp paper towels and keep them in the fridge, getting them out when you need fresh ones. 

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Last year, I planted milkweed in our garden in hopes of getting caterpillars right in our own backyard and it worked!  Plant some this fall or next spring if you want your own butterfly garden.  It’s a great way to help the butterfly population.

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Once you have your caterpillar, all you have to do is make sure it has plenty of leaves to eat.  Occasionally, have your child dump out the caterpillar poop, of which there is a surprising amount.  Get out your child’s science notebook or just some paper and ask them to draw the caterpillar and the milkweed.  When it is ready to form a chrysalis, the caterpillar will hang upside down and look like the letter J.  They can draw that, the chrysalis, and finally, the beautiful  butterfly that emerges!   Have them write the word metamorphosis in their notebooks. (It’s a great word.)

A few years ago, my kids and I were lucky enough to see the caterpillar turn into a chrysalis.  It only takes a few seconds and is easy to miss, but it is truely amazing.  If you and your child are lucky and patient, you may see it too.  If you miss it, look on line and you can probably find a slow motion video of it.  You can also look up a picture of a Monarch’s egg.

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There’s nothing like taking the lid off your butterfly house and watching your Monarch soar away.  It’s a great moment to share with your own little caterpillar.

More Backyard Science- Tablecloth Trick

July 30, 2009

This is a fun experiment to try outside, on the grass, where your kids can spill as much water as they want to.   All you need is a table, a sturdy glass that won’t break if it falls on the grass, a slippery tablecloth and water.

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We used easel paper as our tablecloth, but your kids could try a plastic tablecloth or even a cloth one that doesn’t have a heavy seam on the edge.  The more slippery the tablecloth, the better it will work. You’ll also need a fairy heavy glass that is not too tippy.  I used a bar glass and it worked pretty well.  I’d also recommend bringing out a pitcher of water for refilling the glass and a towel.

Have your child put the paper or tablecloth near the edge of the table (see photo above.)  Place the glass of water on the tablecloth.  I wouldn’t recommend filling it to the top.

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This part is important!  Your child must pull the tablecloth straight down, along the edge of the table, very fast.  If they pull it out, toward them, or pull it too slowly, it won’t work.  If they do it correctly (and it may take a few attempts), the water will slosh a little, but the cup will remain on the table, full of water.  We spilled a lot, but had a great time.  All of the older kids involved were able to do it successfully by themselves, but I had to help my three year old a little.

The law of inertia says that objects don’t want to change how fast they’re moving (or not moving, in the case of our glass.)  They heavier something is, the more inertia it has.  In our experiment, the heavy glass of water is standing still and doesn’t want to speed up.  Since the tablecloth is moving under the glass very quickly, the heavy glass slips on it and doesn’t move very far.   It seems like magic, but it’s just physics.

Have fun!

Throwing Eggs-Backyard Physics

June 21, 2009

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Next to the kitchen table, my back yard (or front yard) is my favorite science laboratory.  It has the added bonus of being easy to clean up.  For this fun, messy experiment, a hose and a few paper towels did the trick. 

My dad, who is a physicist, told me about this great demonstration that teaches kids a little bit about motion and force while letting them do something that they are rarely, if ever, allowed to do- throw eggs!  All you need is a sheet, some clothespins or string, raw eggs, and some paper.  You could use newspaper or easel paper.  It is just to make cleaning up easier.  I also used a portable table turned on its side as a wall, but you could just use a wall and have your child hose it off when you are finished.

Hang the sheet up from a tree, if you have one.  If you don’t have a tree, you could hang it from anything else, or have two tall children or adults hold it.  Then have two children hold the bottom of the sheet up, or tie it to chairs  so it makes a J shape when you view it from the side.  The idea is to keep the eggs from hitting the ground and breaking. 

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Have your child throw a raw egg at the sheet as hard as they can.  It won’t break because the sheet slows the egg down.  The law of motion says that the faster you change speed, the greater the force.  When you change the speed of the egg slowly, like the sheet does, it lessens the force of the egg stopping and the egg remains intact.

Now, put some paper on a wall (or table like we did.)  Have your child throw the egg at the wall.  They will see what happens when something stops fast.  Once again, the law of motion rules.  When you change the speed of the egg quickly, it stops with a lot of force.  SPLAT.  My kids loved this part.  I had to stop them from using all my eggs. 

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Tell them that this is one reason they put airbags in cars.  If a car is moving and hits something, causing it to stop very quickly, the airbag act like the sheet, slowing the person in the car down and greatly reducing the amount of force they might hit the dashboard with. 

Have your child record their results in their science notebook, if they want to.  They can write or draw what they did, write the word force and record how many eggs they threw and which ones broke. 

Finally, make sure they wash their hands when they’re done playing and cleaning up.  Remind them that raw eggs can have a bacteria called Salmonella living in them and on them. 

Have fun!

Dandelion Curls

May 13, 2009

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My daughters were playing tug-of-war with a chrysanthemum size dandelion today when it’s “head” popped off.  As tears ensued,  I recalled a making dandelion curls as a child and assured them that we could do something really fun with the stem.  This is so simple, I hesitate to post it, but my daughters are hooked.  They’ve spent the last half hour running outside to find more dandelions.  They ooooh and aahhhhhhhh every time a new one curls.

You will need dandelions and a bowl of water.  Remove the head of the dandelion and show your child how to split the stem with their fingernail to peel it in half.  Put the stem in the water and voila-dandelion curls.  Shorter pieces will make tight curls.  It’s also fun to leave the flower on and curl the stem. 

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I think the stem curls because the inside of the stem absorbes water, while the outside doesn’t, but I’m not sure.

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It’s good to have a few weeds in your yard.  I’m pretty sure that dandelions are my kids’ favorite flower!

Window Sprouts

April 30, 2009

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When I was growing up, we always had a vegetable garden.  My mom grew up on a farm and was appalled when my sister or I would throw a fit upon finding a tiny bug in our lovely, homegrown lettuce salad.  “Where do you think the lettuce came from?” she would ask, and we’d have to admit that it grew in dirt, outside, and that there are bugs out there.  It was an invaluable lesson and one I hope I can pass along to my kids.  Our world has become too sterile and disconnected from nature.  Like plants, we need dirt, sunshine, fresh air and clean water to survive.  Who cares about a few bugs?

 Today, I thought we’d get a jump on the gardening season by starting a few bean and pea sprouts in plastic bags.  It’s a perfect project for my three year old.  She’ll love to check them every day to see what’s happening, and when it’s warmer, we can transplant them to the garden!  I’m sure my older kids will plant sprouts of their own when they see their sister’s!

You’ll need a few plastic zip-lock bags, dry beans from your pantry (or peas and beans from the garden seed packs you can find almost anywhere ), paper towels and water.  Cut a paper towel so that you can fold it a few times and it will fit into the zip-lock baggie.  Have your child soak it with water and help them put it into the bag so that it’s relatively flat.  Then, give them two beans or seeds to place in the bag, near the bottom.  I had to stuff a little piece of paper towel into the bottom of the bags so that the seeds wouldn’t sit in the extra water at the bottom.  Let your child help seal the bag.  Leave an opening near the top so the plants can get some air.  Finally, tape the bag in a window with the beans facing you so that your child can watch them as they grow.  (I’d recommend finding a window where they won’t get blasted by hot sun all day, or they might fry.)

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As you do the project, ask your child what they think plants need to grow  (Plants need light, air, water and nutrients, or “food.”)  Ask them how they think the seed can grow without the dirt as “food.”  Tell them that when a plant first sprouts, it gets its nutrients from the seed itself.  They can watch the seed shrink as the plant grows.  Have them draw the seed/plant in their science notebook as it changes.  Older kids can measure the plants as they grow.  Eventually, you should be able to transplant them to a cup with dirt, or directly into a garden.  You may have to add water to the paper towels if they dry out.  Play it by ear. 

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Go ahead!  Plant a garden this spring, even a very tiny one in pots!  Let your kids get their hands in the dirt.  Help them nurture plants that will eventually nurture them. (Children are much more interested in tasting vegetables that they’ve grown themselves. ) It is one of the most rewarding activities you can do with your children, and takes only dirt, seeds and water!  Find your inner farmer and let your children find theirs- organic food is cheap when you grow it yourself!

Coin Batteries

April 19, 2009

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They say the penny is, or will soon be, obsolete.  I beg to differ.  My kids had a great time sorting, bouncing and stacking pennies for this project.  We even learned a little bit about this humble coin as we figured out the best way to do the experiment.  Using only coins, paper towels and vinegar, your child can make his or her own wet cell, a kind of battery.  

It’s a safe, easy way to experiment with electricity using pennies and other coins as electrodes (which collect charge) and vinegar, lemon juice or salt water as electrolytes (which pass the charge, or electrons, from coin to coin).  Holding this homemade battery between two wet fingers completes the circuit and sends a tingle of electrical current strong enough for your child to feel!  It’s a little complicated, but you can explain that you are making a battery, similar to one in a flashlight, and that the coins are like the two different ends of any battery, with a positive end (+) and a negative end(-).

What you will need:  10 or more pennies, 10 or more non-metal coins (quarters, dimes or nickels), paper towels, vinegar, salt water (optional) and lemon juice (optional)  For simplicity’s sake, I’m going to call the non-copper coins quarters as I describe the experiment, but any of the non-copper coins I suggested may be used!

First, have your child sort the pennies into two piles: pennies made before 1982, and pennies made after 1982.  Keep any pennies made in 1982 in a separate pile. Pennies made before 1982 are 95% copper, those made after 1983 are 97.5% zinc with a thin copper coating.  Pennies made in 1982 could be either zinc or copper.  All pennies will work, if you don’t have enough of one kind or another, since the current travels through the copper surface on the coated ones. 

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Pour some vinegar in a bowl.  Have your child cut the paper towels into small squares around a half an inch on each side.  Then, have them soak the paper towel pieces in the vinegar.   Stack ten pennies and ten quarters with a piece of soaked paper towel between each coin (e.g. penny, paper towel, quarter, paper towel, penny, paper towel and so forth.)  Be sure to alternate penny, quarter, penny, quarter!  It works best if the pieces of paper towel aren’t touching each other.  We made ours a little too big, as you can see.  

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Finally, have your child wet one fingertip on each hand and hold the pile of coins between those two fingers.  (See photo at top of this post!)  They should feel a slight tingle as the electricity flows between their fingers!  I had to hold the stack for several seconds before I felt anything.

Let your child try other variations on the experiment if they’re interested!  See how well lemon juice works as the electrolyte.   Ask them what vinegar and lemon juice have in common. (They’re both acids!)  Try salt water as the electrolyte. Do the pennies made before 1982 make better batteries than the new zinc pennies?  Have them bounce the copper and zinc pennies on a linoleum surface.  They should make slightly different sounds.  Can they determine whether the 1982 pennies are copper or zinc by the sound they make?  Did the vinegar make the old pennies shiny?  Why? 

Pull out those science notebooks and have them record their results!  They can record their results, draw a coin battery, make a graph of how many pennies they had from different years, or even do some penny rubbings with a pencil!

Red Cabbage Litmus Paper (or Play with your Food and Eat it too!)

March 17, 2009

With St. Patrick’s Day right around the corner, I thought that this would be a fun project and that people might already have cabbage on their grocery lists for the Irish holiday. 

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All you will need is a head of red cabbage and some paper towels.  Alternately, you can just use the juice from canned red cabbage.  I recommend having your child wear an old tee shirt or a home-made lab coat, since I’m guessing that cabbage juice will stain.   To make a lab coat, just have your child write their name in permanent marker on the pocket of a man’s old button-down shirt.  They’ll love it! 

Chop half a head of red cabbage into small pieces and add it to a pan with about a cup of water.  Boil the cabbage uncovered for about 15 minutes, stirring occasionally, let it cool, and strain the juice into a jar or bowl.  (Save the cooked cabbage for your favorite recipe and make cole slaw with the other half!)

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Have your child cut the paper towels into strips about an inch wide and a few inches long and soak them in the cabbage juice for about a minute.  Remove them and let them dry on something that won’t stain.  I blotted them a little to speed up the drying process.  You might even try using a blow dryer!

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When dry, your litmus paper will be ready to use for testing acidity.  Your child can dip the paper into orange juice, soapy water, lemon juice, baking soda in water, baking powder in water, vinegar, and anything else they want to test.  The paper will turn red-pink in acids and blue or green in bases.  Even very young children will enjoy watching the color change!  The colors we saw were amazing.  I think the kids may make a collage with their litmus paper when it dries.  You can also have them tape a strip or two of the paper into their lab notebooks.

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If they ask what an acid is, you can first tell your child that everything in our world is made of very tiny pieces called atoms.  Atoms are so small that if you blow up a balloon, it will contain about a hundred billion billion atoms of the gases that make up air.  Atoms are often bonded to other atoms to form a group of linked atoms called a molecule.  A water molecule, for example, has two hydrogen atoms and one oxygen atom, bonded together. 

Then, explain that acids are substances that usually dissolve in water to form free-floating hydrogen atoms.  Bases are the opposite and take up free hydrogen atoms.  The molecules in the cabbage juice litmus paper change when exposed to an acid or base, making the paper change color. 

Now I know why my mom’s delicious Pennsylvania Red Cabbage recipe turns red when we add the vinegar!

Fizzy Balloons

March 2, 2009

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I was never an enthusiatic chemistry student.  However, even I have to admit that chemical reactions can be lots of fun to watch.  Things can turn different colors, or smell different.  They can change from liquids to solids and they can even explode, among other things. 

There are many fun, safe chemical reactions you can perform with your kids.  I’d recommend having them put on safety goggles or sunglasses, if you have them, for most experiments where you mix things together.  As you can see, my children aren’t wearing any eye protection for this project, but I did have them stand back to make sure the balloon wouldn’t explode the first time we did it.  Just use common sense.

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You will need: a balloon, an empty soda bottle, white vinegar, and baking soda.  Put 1/4 to 1/2 cup vinegar into the soda bottle.  Then, hold the mouth of the balloon open and have your child pour about a teaspoon of baking soda into the balloon.  Shake the soda into the “bulb” or the main part of the balloon.  Then,  stretch the mouth of the balloon over the mouth of the bottle, trying to keep the main part of the balloon off to the side (so the soda isn’t dumped into the bottle right away.)  Ask them what they think will happen when you mix the two things together. Finally, let your child shake the soda into the bottle, all at once. 

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Stand back and watch what happens!

If the seal is tight, which it should be, the reaction between the soda and the vinegar will form a gas that inflates the balloon.  Our balloon was big enough that it didn’t explode, but if your balloon is over-inflating, simply take it off of the bottle.  Just pay attention and you’ll be fine.

What happened?

Baking soda is a chemical called sodium bicarbonate. Vinegar is called acetic acid. These two chemicals react to form some different chemicals.  One of these is carbon dioxide gas.  This is called a chemical reaction.  The gas is what inflates the balloon.  We know a reaction is happening because we can see bubbles forming.  What else do your kids notice about the reaction?  Have them record (or help them to record) what they see in their science notebooks.  Older kids can draw what they see and then try to describe it.  My kids loved it when I wrote down their descriptions for them before they could write. Have them touch the bottle.  Does it feel warmer or cooler than room temperature?  A temperature change is also a clue that a chemical reaction is occurring!  They could even time how long it takes for the balloon to inflate. 

My kids did this experiment three times and I cut them off.  They thought it was pretty great.  Give it a try!  Put those budding brains to work!

Magic Marker Chromatography

December 3, 2008

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This is one of those projects that kids will take in many different directions, which is what science is all about!  Just get them started and leave them alone to experiment.  It’s safe, easy, fun and they’ll love it.

Chances are, you have all the supplies you need for this project in your kitchen right now: coffee filters or paper towels, magic markers, and water.   

Fill the bottom of a bowl or glass with a little water.  Then, cut paper towels or coffee filters into long strips.  Have your child draw a large dot of color (black works best) about an inch from the bottom of the strip of paper.  Help them place the bottom of the paper, below the dot, into the water.  Once the water starts moving, the paper will stick to the side.  You can also hook it over the top, like we did.  They’ll quickly get the hang of it!

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The water will be wicked up the paper and through the dot, dissolving and taking some of the dye up the strip with it.  You will be able to see colors separate as the dyes travel up the strip. It’s fun to see what colors make up different black inks.  My kids tried it with colors other than black too.  They even made dots comprised of several different colors and watched them separate in the water.  You can also put ink on a large piece of paper, drip water on it from a dropper or straw and watch the color travel out in a circle!

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We taped some of the strips into our science notebooks.  They’re very colorful. Tell your children they did chromatography when they separated the colors from one another on the paper!   Older children might enjoy trying a 10:1 mix of window cleaner and vinegar to separate the colors (with adult supervision.)

If they want a more scientific explanation, tell your child that when paper is dipped in water, water molecules make it wet.  The water molecules travel up the paper towel. When the water reaches the ink, it dissolves some of the dyes in the ink, and the dyes travel up the paper towel with the water. Some of the molecules that make up the dye are smaller and travel up the paper towel faster than the larger ones and you can see some of the different colors that make up the ink separate from one another.   The number of spots of color you see can tell you how many chemicals make up the color in your marker.

Pull out the markers, get the kids started and put your feet up for a little while.  You deserve it!

Liquid or Solid?

November 1, 2008

This project is easy, non-toxic and so much fun that it is worth every bit of the mess it makes.   Your kids will love it and it is easy to clean up. 

All you need is a cup of cornstarch and half a cup of water.  Let your child measure everything out.  (He or she will enjoy it much more than you will.)  Simply add the two ingredients to a medium-size bowl and let your child mix them together with a spoon or their fingers.

Then, play with it!  You will discover that it behaves like a solid when you agitate it, or move it quickly,  and like a liquid when you let it sit still.  Pour some onto plates or into bowls if you want to.  We just poured it directly onto our table which was pretty messy, but lots of fun!  Hold a handful on your palm and watch it drip between your fingers!  Have your child roll it into a ball.  If it gets too dry, just add a little more water.

Cornstarch molecules are like long ropes.  When you leave them alone, or move them slowly, they can slide past each other and look like a liquid.  However, if you squeeze them, stir them or roll them around in your hands, the ropey molecules get “tangled up” and they look and feel more like a solid.

Have fun! (Click here to see my video on how to make cornstarch goo.)