Posts Tagged ‘Science’

Oily Experiment

May 3, 2010

The oil spill in the Gulf of Mexico is devastating news to the already fragile and damaged ecosystems in the area.  To demonstrate how hard it is to remove oil from water, and what materials work best, I found this experiment online at tryscience.org and decided to have my kids try it.  It was messy and disgusting and oil got all over everything.  In other words, it was a great demonstration of how hard it will be to clean up the mess made by BP’s Deepwater Horizen oil rig, which exploded on April 20th.

Polyester scraps soak up oil.

 

You’ll need a clear bowl, water, yellow oil (vegetable, corn or canola will work,) cotton balls, cheese cloth, polyester cloth (the website said polypropylene, but I couldn’t find any,) feathers, and a spoon.

Help your child put some water in the bowl and pour in some oil.  I probably added a cup so it would cover the water.  Then, using spoons and the other materials, have them try to remove the oil from the water.  What works best? 

Oil is hard to clean off feathers.

 

We put our feathers in oil and then tried to clean them off using dish soap and water, which is how they clean off marine birds covered with oil following oil spills.

Polypropylene is a synthetic material made from Carbon and Hydrogen, the same elements in oil.  Oil is attracted to polypropylene, and both float on water, so polypropylene is often used in cleaning up oil spills.  You can also find it in gloves and sock liners. 

If one cup of oil is this hard to clean up, can you imagine the mess pouring into the Gulf of Mexico right now, at the rate of about 210,000 gallons a day (according to the New York Times?)  I’m attempting to find out if there’s any way to help, aside from travelling to the area to help clean off wildlife by hand.  As soon as I learn anything, I’ll post it here!  Here is a link to a map that is tracking the spill.

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Sweet (and Salty) Lava Lamps

March 3, 2010

Pull out a jar, a bottle of vegetable oil, some food coloring, salt, sugar, and water to mix up this easy experiment! 

Fill the jar about halfway up with water and add a few drops of food coloring for contrast.  Add about half as much vegetable oil to the jar and watch it float to the top.  Now, a spoonful at a time, add salt to the jar.  The salt will pull some of the oil down with it, but will release the oil as it dissolves and the oil will float back to the top.  This will make your science experiment look like a real lava lamp.  Keep adding salt to make it keep working.  Now, try adding sugar or even sand. Kosher salt worked really well!

What worked the best for you?  Do you know why oil floats to the top of the water?  Email me your answers in the comments section at http://kitchenpantryscientist.com for a chance to win a KitchenPantryScientist.com tee shirt (size M.)  I’ll do a drawing for a winner in two weeks!

Fingerprint Valentines (plus a little science)

February 5, 2010

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For this project, I thought that it would be fun mix a little science and a little art.  My sister told me that you could make cute Valentine’s cards using fingerprints.  I’ve also heard that it’s pretty easy to lift fingerprints using scotch tape, so I thought we’d give it a try.  For the valentines, you will need an ink pad, paper and markers.   All you need for the science part is paper, scotch tape and a pencil. 

VALENTINES: For the Valentines, have your children put ink on their fingers and make fingerprints or thumbprints together in the shape of a heart.  Of course, they will also want to make fish, bugs, and who knows what else?  I gave my kids some ideas to get them started and they went from there! They can decorate with markers.  It’s lots of fun!  We got our stamp pads at Creative Kidstuff, but you can find them almost anywhere.  There are few things better than a homemade Valentine!  Have your kids make them for the people they love!  Last year, my kids made them for everyone in their class.

SCIENCE:  On www.wikieducator.org/Fabulous_Forensic_Fingerprints, I found a fingerprint-lifting technique that works well, even for very young children.  Simply take a pencil and scribble on a piece of paper until a small area is covered with the graphite from the pencil lead.  Have your child rub his or her finger around in the graphite until it is covered with gray.  Then, have your child carefully place their finger on the sticky side of a piece of scotch tape.  Have them lift their finger off of the tape.  A clear fingerprint should be visible.  Place the tape face-down on another piece of paper. 

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Your child can then inspect the fingerprint under a magnifying glass, or just with their naked eye.  If you go to the wiki website I mentioned, your child can decipher whether they think their fingerprint is a whorl, a loop, or an arch.  It would be fun to have them trace their hand, fingerprint each finger and thumb, and tape their fingerprints to the correlating finger.  This would be a great addition to their science notebooks!  I’ve found that their notebooks are great keepsakes of their drawings and observations at different ages.  The kids had a lot of fun with this project and could do it unassisted once I showed them what to do.

Magic Bag

January 25, 2010

Your kids will be amazed when they fill a plastic zip-lock bag with water and poke sharp skewers through, only to find that the bag does not leak!  All you need is a ziplock bag, water and wooden skewers.  It’s another great project from the Dragonflytv website!  Just remind them to watch the sharp points.

Have your child fill a quart-sized ziplock bag with water and seal it.  Let them poke several wooden skewers completely through the bag, from one side to the other, avoiding the part with air in it.  See how many they can push through!

When they ask you why it doesn’t leak, tell them that the plastic makes a seal around the spot where the skewer is poking through.  The bag is sealed and contains very little air, so there isn’t much pressure pushing on the water. Now, let your child take the bag to a sink or bathtub and either push a stick through the part of the bag holding air, or remove the stick and they will find that the bag leaks like crazy!   

If they want to, let them draw a picture of what they did or record their results in their science notebook.  Have fun!

Snow Science

December 29, 2009

A fun fact from NGKids :

“Bet You Didn’t Know: Twenty inches of snow equals one inch of water on average.”

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Try it!  Have your kids put some snow in a clear container, let them measure how deep it is and allow to melt.  Then, have them measure how deep the remaining water is.  Older children can figure out whether their results were consistent with the NG Kids fact (10 inches of snow* should melt down to around 1/2  inch of water or 50cm of snow* should melt down to 2.5cm.)  If the snow isn’t perfectly fresh, this experiment may have the added benefit of reminding them why they shouldn’t eat snow.

*I’m guessing that NG Kids was referring to unpacked snow.  Our kids packed the snow into containers and we go more water than we expected.  Ask your kids why they think packed snow melts to give you more water than unpacked snow.

Handwashing Lesson (Homemade Petri Dishes)

November 13, 2009

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With all of the bugs going around at this time of year, I thought it would be a great time to remind your kids why they need to wash their hands.  Culturing microbes (bacteria and fungi) on petri dishes lets them test different surfaces for microbes and grow their own germs.  Even very young children will have fun helping with the Q-tips and seeing what grows in their microbial zoo.  It’s fun, easy, and you probably have what you need in your kitchen cupboard:

IMG_3658disposable containers to grow bacteria in (see below),  beef bouillon cubes or granules, plain gelatin, water, sugar and Q-tips.

For containers, you can use foil muffin tins, clear plasticware with lids, or real petri dishes to grow fungi and some bacteria.  We’re going to use clear deli containers so that we can recycle while we learn.  (They look like they will be heat-resistant enough to pour warm agar into.)  You’ll start by making microbial growth medium (or germ food, as we like to call it.)  Help your child mix together a little less than 1 cup water, one package gelatin, one bouillon cube (or 1 tsp. granules), and 2 tsp. sugar.  The next step is for an adult to do.  Bring the mixture to a boil on the stove, stirring constantly, or boil in the microwave, stirring at one minute intervals and watching carefully.  Don’t stir after the liquid boils.  Remove the boiling liquid from heat and cover it with aluminum foil.  Let the growth medium cool for about fifteen minutes.

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Pour the medium carefully into clean containers, until 1/3 to 1/2 full.  Loosely place lids or foil over containers and allow dishes to cool completely.  The agar should make the growth media hard like jello.  When the agar has hardened, store the plates in a cool place, like a refrigerator, before using.  Plates should be used in 2-3 days.  When you are working with the plates, try to keep the lids on whenever possible, so that they are not contaminated by the air.  If you’re planning to use muffin tins, simply place them in a muffin pan, fill them with agar, and when they’re cool, put them in individual zip-lock baggies.  With other containers, put the lids on tightly once the plates harden. 

When the plates have hardened  and you’re ready swab, shake the condensation off the lids of the containers and put them back on.  Then, help your child draw a grid of four sections on the bottom of the plate with permanent marker. (If you are using muffin tins, you’ll just label each bag with the surface you are checking.)  Ask your child which surfaces they’d like to test.  It’s always fun to label one section of the grid “fingerprint” to let them see what grows when they touch their finger to the plate.  Label each section with the surface they want to test.   Be sure to label the bottom of the plate since the lid will move.  You should be able to see through the agar to see your lines and your writing.  If you want to, you can label a separate plate for each surface, but we had three kids and three plates, so we made sections.  TV remotes, kitchen sinks, computer keyboard, doorknobs and piano keys are great surfaces to check.  See the photo at the top of this post for a better picture of how your plate might look.

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Now comes the fun part.  Have your child rub a clean Q-tip around on the surface they want to test.  Then, remove the lid from their plate and help them rub the Q-tip across the section of the plate labeled for that surface.  If they are gentle, the agar shouldn’t break.  If it does, it’s no big deal.  When you have finished, set the plates on a flat surface with thier lids loosely set on top (do not invert them, as I first suggested.)  I set our plates on a countertop where they won’t be in the way.  Have your children check their plates every day, and soon they will observes colonies of different shapes, sizes and colors starting to grow.

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They will mostly see fungi (molds), but they may also see some tiny clear or white spots that are colonies formed by millions of bacteria.  Your child can record and draw how their plates look in their science notebooks.  Older children can keep track of how long it takes things to grow and the shapes, sizes and colors of the microbial colonies that grow on their plates.  If they want to learn more about microbes, help them search for the words fungi and bacteria on the website cybersleuthkids.com and it will give them some great links to microbiology websites.  Tell your children that microbes are everywhere, but that very few of them are harmful, and that many of them are essential for good health.

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Have your children wash their hands after handling the plates, and throw the plates  away when you are done.  Remind them that if they wash their hands with regular hand soap for the length of time that it takes to say the ABCs, they’ll remove most of the harmful bacteria from their hands.  (For adults, a severe side effect of this experiment is the sudden urge to disinfect computer keyboards and remote controls.)  

Here’s what grew on our plate: The large, fuzzy colonies are fungi and the small, whitish ones are probably bacteria.  The grid with the most fungi was cultured from our piano keys.  The one with both fungi and bacterial colonies visible was cultured from our bathroom sink.  One grid has mostly small, white bacterial colonies and was cultured from a water-glass my son drank from.  The fingerprint grid has only a single fungal spot.  My daughter must have washed her hands before touching it!  Our other two plates were pushed too close to the under-counter lights in our kitchen and the agar melted, so we threw them away.  I’m going to clean off my piano keys now!

Cornstarch Goo- Liquid or Solid?

November 3, 2009

My son, the science-nut, turned nine on Tuesday, so I’m posting one of his favorite projects.  It’s easy, non-toxic and so much fun that it is worth every bit of the mess it makes.   Your kids will love it!

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 the mixture!  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 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!

Pizza Box Solar Oven

October 9, 2009

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When my friend Sheila, who works at NREL (the National Renewable Energy Laboratory) sent me this project, I couldn’t wait to try it out.  Unfortunately, it’s fall.  That means it’s cool outside and the sun isn’t very high in the sky.  We decided to attempt the project anyway on a cool, 60-degree day and, much to my surprise, it worked.  The oven didn’t get very hot, but we were able to warm a chocolate chip cookie enough to make it soft and melt the chips at about five o’clock in the afternoon with only about half an hour of sun.  NREL suggests using your oven to make s’mores, which would be really fun.  I just didn’t have the ingredients on hand.  The solar oven is surprisingly easy to make.  I think it only took us 10 or 15 minutes, with my help.

You will need: 1 pizza box from a local pizza delivery store (Little Caesars, Domino’s, Pizza Hut, etc.), newspapers, tape, scissors, black construction paper, clear plastic wrap, aluminum foil and a dowel or stick to prop the lid up.  You will also want to have some food to warm in your oven-marshmallows, chocolate, etc.

Make sure the cardboard is folded into its box shape.   Carefully cut out 3 sides of a square in the lid of the box.  Do not cut out the fourth side of the square, which is the one closest to where the pizza box lid hinges.  Gently fold the flap back along the uncut edge to form a crease.  See photo below!

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Now, Wrap the underside (inside) face of the flap that you made with aluminum foil.  Tape it so that the foil is help firmly but so that there’s not too much tape showing on the foil side of the flap. 

Open the box and place a piece of black construction paper so that it fits the bottom of the box.  Tape it by the edges. (We used two pieces.)

Roll up some newspaper and fit it around the inside edges of the box.  This is the insulation.  It should be about 1-1 ½” thick.  Use tape (or other materials you can think of) to hold the newspaper in place.  Tape it to the bottom of the box so that you can close the lid. (We taped it to the sides and had to cut the tape so that we could close the lid.  Luckily our newspaper fit in tightly enough that we didn’t really even need the tape.)

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Finally, cut plastic wrap an inch larger than the lid opening on the box top.  Tape it on the underside of the lid opening.  Add another piece of plastic wrap to the top of the lid opening.  This creates a layer of air as insulation that keeps heat in the box. It also makes a window your children can look through at the food they’re “cooking.”  BE SURE THE PLASTIC WRAP IS TIGHT.

You are almost done!  According to NREL, the oven needs to sit at an angle facing the sun directly so you’ll need to make a prop.  You could probably just use a book or something under the hinged side of the oven.  However, I missed this when I read the directions and we just put it flat on the ground.  The flap of the box top needs to be propped open—a dowel or ruler works great.   We used a wooden skewer that I broke the sharp point off of.  This way your child can change the amount of sunlight striking the oven window.  Let them play with the angle of the flap to see how much sunlight they can get to reflect on their food. 

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Your child can check every once in a while to see how well their food is being heated by solar thermal energy.  Best of all, the results of this experiment are edible!  If your child is interested in finding out how the sun cooked their food, go to http://www.nrel.gov/  NREL’s website has great information on solar energy and many other sources of renewable energy.

Tie-dye Milk

September 29, 2009

I’m reposting this experiment in honor of my daughter’s classmate, Timmy, who passed away two weeks ago.  He was an amazing little boy who loved tie-dye and rainbows and inspired everyone who met him.  Even if your kids are driving you crazy today, hug them, look them in the eye and see them for the wonderful gifts that they are.

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Food coloring isn’t just for frosting any more!  You and your child will be amazed as you watch the forces of surface tension at work in this “brilliant” experiment. 

All you’ll need is a small, shallow dish or plate, milk (2% or whole milk work best, but skim milk works too,) dishwashing liquid, Q-tips and food coloring. 

I would recommend putting down newspaper and having your child wear an old shirt, since food coloring stains. You can even help them make a lab coat from an old button-down shirt, by writing their on the pocket with permanent marker.  

First, add enough milk to cover the bottom of the dish.   In a separate small container, mix together about a half cup of water with a squirt of dish-soap (a teaspoon or so.)  Have your child put several drops of different colored  food coloring into the milk (maybe two drops of each color.)

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Finally, let them dip a Q-tip into the dish-soap mixture and then touch the Q-tip to the milk.  The detergent will break the surface tension of the milk and the food coloring will swirl around in interesting patterns, as if by magic. 

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Let them play with it!  It works better if they don’t stir, but they can keep re-wetting their Q-tip with soapy water and touching it to the milk.  If you want to, have them compare how the experiment works with skim milk versus whole milk.  Your sixth-grader will love it as much as your two-year old does!

Have your child draw a picture in thier science notebook of how the milk looks before and after they touch it with the Q-tip!  Help them take a picture of it and tape it their notebook!  Can they write the words “surface tension”?  Help them describe what they see with words or pictures!

What Happened?  Imagine that surface of liquids is a stretched elastic skin, like the surface of a balloon full of air. The scientific name for the way the “skin” of a liquid holds together is surface tension.  When the skin of the liquid is broken, whatever is underneath will be able to escape, like the air rushing out of a balloon. 

In this experiment, the surface of milk is like the elastic skin and dish detergent is what breaks the “skin” of the milk, sort of like a pin popping a balloon.  Food coloring and more milk then escape from underneath the milk’s surface, swirling to the top.

Have fun!  Click here to see my video on how to make tie-dye milk.

Growing Crystals

September 20, 2009

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Patience is tough for kids, especially in today’s world of instant gratification.  In this experiment, your kids will put a string in some colored salt water and watch and wait for crystals to grow.  The crystals aren’t huge and spectacular, but your child can see them and a magnifying glass makes them easier to inspect.

All you’ll need is a clear container or containers, water, salt, food coloring and string.  We used both kitchen twine and jute twine to see what would happen.  The kitchen twine is white and worked well, but the jute twine didnt’ work at all.  

First, have your child put a few drops of food coloring in the container(s) that you are using.  Then, have them cut a piece of string about six inches long.  It doesn’t have to be exact.  Help your child tie a knot or two at each end of the string.

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Boil some water (a cup or two) and, when it is boiling, start adding salt to the water.  Add a tablespoon at a time, stirring the mixture to dissolve the salt.   Do this until no more salt will dissolve (you’ll see salt and it won’t go away no matter how much or how long you stir.)  At this point, you can let the mixture cool a little so it’s not dangerously hot.

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When cool, pour an eighth cup or so of the salt solution you’ve made into the container(s) containing food coloring.  Let your child mix it and then have them place one end of the string into the colored salt solution.  They may have to swish it around to get it to soak up the salt water since the string will want to float.   Leave the other end of the string hanging over the edge of the container.IMG_3309

As the water evaporates, the salt that the string has absorbed will remain in the fibers on the string and form new, larger crystals on the string.  Have your child check the string every day and, if they want to, record the results in their lab notebooks.  It may take several days before the water evaporates and the salt crystals form – it took ours five days to evaporate.  Try not to let the end of the string that hangs over the edge of the jar or glass touch the counter, or the salt water will be wicked onto the countertop.  As I said before, a magnifying glass is a fantastic way to look at the crystals that form on the string.  Ask your child what shape the crystal are-cubes, spikes?  What do they see?  If they’re interested, have them draw the crystals and record their observations. 

There are great books on crystals and gems at the library.  Check them out!