Science in the Park - Balloons

This week blew up balloons a few different ways!

Experiment 1:

In this experiment, the kids used hot air to blow up a balloon.

How to:

• Take a balloon and stretch it out over a plastic water bottle. 
• Put the bottle in a bowl of very hot water. 
• The hot water will warm up the air in the bottle causing the balloon to inflate a little.

The Science:
The heat causes the air in the bottle to warm up.  Since hot air "expands" (the molecules are moving fast) and it needs more room so it pushes on the balloon inflating thus balloon a little.

Experiment 2:

In this experiment we blew up a balloon using a chemical reaction. 

How to:

• Add about 2 tsp of baking soda to a balloon.  Add it inside of the balloon.
• Pour 1 cup of vinegar into a plastic bottle.
• Stretch the balloon on top of the bottle being careful not to dump the baking soda in.

• Once it's on - lift the balloon up dumping in the baking soda and blowing up the balloon!

The Science:
The baking soda (base) and the vinegar (acid) react to form carbon dioxide and water.  The carbon dioxide that is produced is what blows up the balloon!

Enjoy!

Science in the Park - Exothermic Reactions

This week - we are focusing on exothermic reactions!  These are reactions that produce heat that the kids can feel!

"Elephant Toothpaste" Experiment

This experiment is called "elephant toothpaste" because the foam that is made is supposed to look like toothpaste that would work for an elephant.
Materials:
Yeast
Warm water
Dish detergent
Food Coloring
Plastic water bottle
Hydrogen Peroxide (3% from the grocery store is fine)
Tin trays (to control the mess!)

How to:
Dissolve the yeast in the warm water - about 2 tablespoons of water for every teaspoon of yeast.
Add the peroxide (about a half cup), a squirt of dish detergent, and a few drops of food coloring to the water bottle.
Add the yeast/water mix to the bottle.
The mixture will foam and pour out of the top of the bottle and into the tray.
Ask the kids to touch the bottom of the bottle - it is warm!

The Science:
The hydrogen peroxide naturally breaks down into water but the yeast speeds up this decomposition!  The yeast acts like a catalyst, decomposing the hydrogen peroxide into water and oxygen which is why the reaction is bubbly and foamy!

Hot Ice Experiment

This experiment creates a supercooled liquid that can quickly turn to solid and gives off heat in the process!

Materials
Baking Soda
Vinegar

How to:
Put 4 cups of vinegar in a sauce pan.  Slowly add 4 tablespoons of baking soda (it will fizz).
Heat until boiling and then keep cooking it until most of the water has boiled away and a film is left on the solution.
There will be foam on the sides of the saucepan, scrap this off and save it.
Once about 90% of it has evaporated, remove it from the heat and place it in an ice bath or in the fridge until it cools. 
Once cool, it should be in a liquid state.  Add a little bit of the foam that was scrapped off earlier and the hot ice will crystallize turning into a solid!  In the process it gives off heat!

The Science:
The boiled down vinegar and baking soda mixture is a supercooled sodium actetate solution.  When the solid sodium actetate and the liquid version mix, it causes the liquid to crystallize and give off heat.  This is what is inside the hand warmer packets!

Enjoy!

Science in the Park - Absorption and Ice Science

This week we talked about 'absorption'.  We first did two experiments to demonstrate how something absorbs a liquid and then built ice castles!

Experiment 1: Celery Experiment

• Add some water and food coloring to a glass (if you plan to send these home with the kids - add it to an old jar).  Red or Blue food coloring will work best. 
• Then take a celery stick and cut an inch or more off the bottom.  It looks really cool if the celery stick has leaves.
• Place the celery stick in the glass (or jar) and wait for a couple hours (check it at 4 hours and 8 and 24 etc).  You should see the color coming up through the leaves. 
• If you break the celery stalk in half, you will see the color in the veins of the stalk (so cool!)

The Science: The celery stalk absorbs the colored water and when you break the stalk open you can see the veins that it traveled through.

Experiment 2: Paper Towel Experiment

• Take a cup (we used yogurt cups) and add some food coloring and water.  Use a primary color.
• Then take another cup and add another primary color food coloring and water.
• Take a paper towel (because we used small cups, we ripped the paper towel in half) and fold it so that it sits partially in the cup with the food coloring and partially in an empty cup. 
• The paper towel will absorb the water and transfer it to the empty cup mixing the two colors in the other cups.  So if you had red and blue in the cups - your middle cup will end up purple!  Don't forget to leave the middle cup empty and to give it 10 minutes or so.

Experiment 3: Ice Castle!

• This was so super cool and the kids just loved it! 
• Freeze a few containers of ice overnight (2 or 3 containers per kid).  I just used whatever Tupperware I had available.
• Give each child a tray to work in, a cup of coarse salt (or regular salt - course just looks neat), and a few cup of food coloring and water. 
• Give them a eye dropper or pipet to use for putting the water on the ice castle. 
• The kids can take the ice blocks and put salt on them to make them stick together. 
• If they add salt to the top of the ice and then pour water over it - it makes holes in the ice.  Then as you drip the colored water on top - you get a really awesome ice castle!

 

 

Enjoy!

 

Science in the Park - Sniffing Science

This week we are having some fun with out sense of smell!

Experiment 1: Smelling Cards

How to:

• Hot glue a cotton ball onto an index card.
• Add a scent to each card. We added: vanilla extract, almond extract, orange juice (squeezed from an orange), cloves, cinnamon, and garlic powder.
• We passed around the bottle/jars with the scents in them so that the kids could see if they could match the scent in the cup to the scent on the index card.

Experiment 2: Balloon Sniffing

This experiment demonstrates the ability for olfactory (smell) particles to pass through the rubber that makes up a balloon.

How To:
Demo how cool it is that you can smell through a balloon. Take a candle that has a glass lid (like a Yankee candle or the cheaper version). Ask the kids to smell the candle with the lid on (can't smell much) - then take the lid off - and then you can smell the candle! Now - take a balloon with a scent inside (I added a little bit of vanilla) and show how you can smell the scent right through the balloon. Point out how you could not smell through the glass but you could through the balloon!

Experiment 3: Scratch and Sniff Pictures

Scratch and Sniff is an example of micro-encapsulation. This is when tiny olfactory (smell) particles are encapsulated by another material and the other material has to be disturbed to allow the smell particles to escape for you to smell them.

How to:

• Mix a kool-aid packet with some water to form the consistency of a paint. Mix at about a 1 to 1 ratio (so 1 tsp of kool-aid and 1 tsp of water).
• Paint a picture using the kool-aid paint.
• Wait for it to dry.
• Then scratch and sniff! Very cool!

Enjoy!

Science in the Park - Ghoulish Science!

This week at Science in the Park - we made slime, goo, and blew up balloons....with a chemical reaction!

Experiment 1: Slime

In this experiment we mixed together borax and glue to form goo-y slime!

Materials:

• Borax (bought it at Target!!)
• Water
• 2 mixing bowls
• Glue

How To:

• Mix 1 teaspoon borax in 1 cup water.
• Mix equal parts glue and water (ex. 1/2 cup water with 1/2 cup glue)
• Add a little bit of food coloring to the glue and water mixture to make it look cool!
• Slowly add one teaspoon of the borax solution to the glue solution and stir.  It will begin to stick together and form into slime! 
• Enjoy playing with the slime!  Wash hands after because the borax is a chemical.

 

The Science:

When the borax, glue, and water are mixed together, long molecule chains are formed.  These chains are called "polymers" which you may have heard when referring to plastics.  Plastics are a type of polymer!

 

Experiment 2: Goblin Goo!

In this experiment cornstarch and water are mixed together to form a fun goo!

Materials:

• Yogurt cup
• Cornstarch
• Water
• Food coloring

How To:

• Mix 1 part cornstarch with 2 parts water (example 1/4 cup cornstarch with 1/2 cup water)
• Add a little bit of food coloring to make it look cool!
• Push your finger in slowly and it will feel like a liquid.  Push your finger in quickly and it will feel like a solid!

The Science:

You just formed a "Non-Newtonian" substance!  This is a substance that doesn't follow Newton's law that a liquid flows at a predictable, consistent rate.  The reason why it acts the way it does is because the cornstarch is very fine and the particles are basically held in suspension in the water (they are not dissolved).  Since cornstarch is unique in that when pressure is applied, the grains of cornstarch will hold their shape and size - it reacts to pressure by holding its shape; but if you move slowly then you are not putting pressure on the grains and they moves out of the way.

Experiment 3: Monster Balloons

This experiment uses a chemical reaction to blow up a balloon!

Materials:

• Balloon
• Vinegar
• Baking Soda
• Water bottle (empty)
• Sharpie

How To:

• Put about a teaspoon of baking soda into a balloon. 
• Fill the water bottle about a 1/3 full with vinegar.
• Holding the ball of the balloon that has the baking soda in it to one side, stretch the bottom of the balloon over the water bottle.
• When the balloon is stretched over the water bottle - lift the ball of the balloon up and shake a little so the baking soda falls into the water bottle.
• The chemical reaction will create carbon dioxide gas that will blow up the balloon!
• Once the reaction is done - tie the balloon and use the Sharpie to decorate!

The Science:

The baking soda is a base and the vinegar is an acid.  When these two mix, they cause a chemical reaction whose byproduct is carbon dioxide which is a gas that blows up the balloon!

Enjoy!

Science in the Park - Oil vs Water

This week we took a look at how oil and water just do not mix! 

Experiment 1 - Fireworks in a Jar!

In this experiment we will be making fireworks while exploring how oil and water do not mix.

Materials:

• yogurt cup (or other small container)
• food coloring
• oil
• spoon
• jar with water in it

How To: Step 1

Put a few tablespoons of oil in the cup and let the kids squirt a few drops of food coloring in it.

Step 2

Stir it up! If you skip this step - the colors will not look as pretty.

Step 3

Carefully pour the oil into the jar so that the oil stays on top.

While you watch the colors will fall through the oil and into the water where they will mix with the water and look like fireworks!

The Science:

The oil is less dense than the water - so it stays at the top of the jar. The food color is not so it slips down and then mixes with the water to create the fireworks!!

Experiment 2

In this experiment we used the principle that oil sits on top of water to paint paper!

Materials:

• Tins
• Water
• Oil
• Food coloring
• Card stock paper (the thicker paper works better)
• Fork
• Pipettes (or eye droppers or spoons if you don't have either)

How to:

• Add just a little bit of water to the bottom of the tin - you need enough to cover the whole bottom of the tray (approximately 1/8 inch).
• In a yogurt cup, mix a little oil with food coloring.  This needs to be mixed vigorously and with a fork.  Eventually (up to a few minutes) it will look like it is blended.
• Then take the pipettes and drop the oil on top of the water in whatever pattern you choose!

 

• Once the oil is added, take a piece of paper and gently lay it on top of the water.  It will soak up the oil and you will see this through the paper.
• Leave it there for 10 seconds or so and then pull it up and you will have a neat design on the paper!

The Science:

The oil sits on top of the water and so the oil mixed with food coloring is what sticks to the paper!  Oil and water do not mix because of the "like dissolves like" principle of science.  What this means is that water is a polar molecule and oil is not.  Since one is "polar" and the other is not - they cannot dissolve in one another; but rather they stay separate.  And since oil is less dense than water - it sits on top of the water. 

Experiment 3

Now that we've played with oil - let's clean it up!

Materials:

• The tin with the water and oil in it from the previous experiment
• A polyester rag

How to:

• Give the kids a small piece of polyester and challenge them to clean up the oil. 
• The polyester will do a decent job of cleaning up the oil!

The Science:

Polyester is a polypropylene - which is made of the same elements as oil (hydrogen and carbon).  These materials attract each other since they are the same; thus the polyester soaks up the oil!

Enjoy!

Science in the Park - Colors!

This weeks science was all about colors!  There were 3 expiements meant to "wow" the kids into guessing what would happen next!

Experiment 1: Coffee Filter Science

Materials:

• Coffee filters
• Yogurt cups with water in it
• Scissors
• Markers

How to:

• Take a white coffee filter and cut it into strips. 
• Draw a thick line about an inch from the bottom with a marker. 
• Place the coffee filter below the marker line in the water and let the coffee filter soak up the water. Then the colors will bleed up the coffee filter paper and will separate.  So if the marker was green, you will see streaks of yellow and blue. 

 

Experiment 2: Magic Spoons

Materials:

• Plastic spoons (preferably white)
• Vinegar
• Yogurt cups
• Baking Soda
• Food Coloring

 

How to:

• Without the kids looking - put a drop or two of food coloring on each spoon. 
• Add a lump of baking to each spoon.
• Fill up the yogurt cups with vinegar.
• Give each kid a yogurt cup and a magic spoon.
• Stir the magic spoon into the vinegar.
• The baking soda and the vinegar react and if you keep stiring - the color is revealed!

 

The Science:

Vinegar is an acid and baking soda is a base.  The acid and base react to form a gas (carbon dioxide) which are the bubbles that excite the kids so much!

 

Experiment 3: Pipette-ing

Next we broke out the pipettes and continued the acid base reactions.

 

Materials

• Pipettes
• more baking soda
• more vinegar
• tray

 

How to:

• Put little lumps of baking soda in the tray.
• Put some vinegar in yogut cups (color them if desired)
• Instruct the kids to use the pipette to suck up some of the vinegar and drop it into the baking soda to get the "fizz".
• This gives the kids a chance to practice using a pipette and it's fun!

 

Enjoy!

 

Science in the Park - Oranges and Colors!

This week - we looked at the buency of oranges and at colors. The kids has a blast!

Experiement 1: The Orange

Materials:

• glass
• orange
• salt

Action!

We first started off with a simple orange and a simple question - would the orange float or sink in a glass of water?

Kids think - it will sink!
Experiement says - it floats!

The Science:

The orange peel acts like a life jacket - it has a bunch of tiny air pockets in the peel that give the orange buoyancy in water.

Next Step

Peel the orange and ask the kids now what they think will happen - will the orange float or sink?

Kids think - Sink!

Experiement says - Sink!

The Science:

This one is somewhat obvious. If we took the life jacket off the orange - then it will sink to the bottom of the glass.

A Twist

Add a few tablespoons of salt to the glass and stir. Ask again - will the orange sink or float in salt water?

Kids think - Sink!

Experiement says - Float!

The Science:

The salt changes the density of the water; making the water and salt mix more dense and allowing the orange to float. This can be "kid" explained by saying that the salt mixes with the water to create a salt-water that has more in it to hold up the orange!

Experiement 2 - COLORS!

In this experiement we will be making fireworks while exploring how oil and water do not mix.

Materials:

• yogurt cup (or other small container)
• food coloring
• oil
• spoon
• jar with water in it

Step 1

Put a few tablespoons of oil in the cup and let the kids squirt a few drops of food coloring in it.

Step 2

Stir it up! If you skip this step - the colors will not look as pretty.

Step 3

Carefully pour the oil into the jar so that the oil stays on top.

While you watch the colors will fall through the oil and into the water where they will mix with the water and look like fireworks!

The Science:

The oil is less dense than the water - so it stays at the top of the jar. The food color is not so it slips down and then mixes with the water to create the fireworks!!

Enjoy!

Science in the Park - Balloon Science

Today's Science in the Park features balloons!  Since it is HOT out here - we are using some regular balloons to inspire conversation and some water balloons to cool off!

Material List:

• baking soda
• vinegar
• balloons
• empty water bottles
• cooler full of water balloons
• straws
• scissors
• tape
• yarn/string
• liquids that smell (ex. mouthwash, vanilla extract, etc)

Experiment 1: Smell the Balloon

Preparation: squeeze a little bit of a strong-smelling liquid into a balloon and then blow the balloon up.  We decided to use bubblegum mouthwash, vanilla extract, and lemon soap.

Action!  The kids took turns guessing what was in each balloon. 

The Science: Balloons are made of a porous material that allows the scents to escape.

Experiment 2: Blow up a Balloon

Preparation: Give each child a water bottle. 

Action! Spoon 3 teaspoons of baking soda into the bottle.  Then add about a 1/2 cup of vinegar quickly.  As it starts to fizz - slide the balloon on top of the water bottle so that the escaping gas fills up the balloon.

The Science: The vinegar (acid) neutralizes the baking soda (base) resulting in water and carbon dioxide.  It is the carbon dioxide gas that blows up the balloon.

Experiment 3: What floats?

Preparation: Give each child a tray of about an inch or two of water in it and a water balloon.

Action! Use the air filled balloon from the previous experiment and the water balloon and see which one floats.

The Science: The water balloon sinks while the air-filled balloon floats.  It's a simple observation but it reinforces that the water balloon is heavier than the air filled balloon and that is why it sank.

Experiment 4: Crazy Balloons

Preparation: Squeeze a water balloon into a deflated regular balloon.  Then blow up the regular balloon and tie it off.

Action! Gently throw the balloon and watch it move around like crazy!  Careful - they pop easily!

The Science: The center of gravity of the air filled balloon is in motion because of the water balloon inside moving around.

Break for a water balloon fight!

Experiment 5: Balloon Rockets

Preparation: Blow up a balloon and tape it to a straw.  Then feed a string through the straw so that the straw with the balloon on it can easily glide along the string.  Add a clothespin to the balloons knot for weight.  Tie something (we used leaves found on the ground) to either end of the string so that the straw/balloon cannot slide off.

Action! Fly the rocket!  Start it at the top of the play structures or stand on top of the picnic tables.  Talk about how to make it go faster! 

The Science: This science is physics.  Put the string at a steep angle and notice how it goes faster than at a small slant. 

Science in the Park - Egg Science

This week's edition of "Science in the Park" featured "naked eggs"!  Naked eggs are eggs that have been soaked in vinegar for a few days dissolving the hard outside shell to reveal the rubber-like insides.  Since the eggs (although very cool) didn't take much time - we did a repeat experiment of "elephant toothpaste" that definitely "wows" the kids.

Naked Eggs

Preparation

1. Soak 2 dozen eggs in vinegar for 4 days (no - it won't smell like anything other than vinegar). 
2. On the night before, gently rub off the remaining "white material" to reveal the naked egg.  I found it easiest to do this under running water.  I started with 24 eggs, but I only got 14 naked eggs (I broke the rest). 
3. After rubbing off the white material, put the eggs back in fresh vinegar and by the next morning, anything I couldn't rub off had come off by itself. 

Experimenting

Material List:

• eggs soaked in vinegar (and transported in the vinegar)
• gloves for the kids so they can touch the eggs
• food coloring for coloring the eggs
• recycled yogurt cups for holding the egg
   

Examination

Most of the experiment is just the egg itself - so start off by examining the egg.

Q&A Conversation Starters:

• Ask: What is missing from the eggs?  When the answer "shell" is given, state that the eggs were put in vinegar for a long time to dissolve the shell.  <The science: the shell and the vinegar have an acid/base reaction!  The shell is made of calcium carbonate and the vinegar breaks it down into calcium and carbon dioxide which are the bubbles that form on top>
• Ask: If there isn't a shell...then what is holding the egg together?  Mention that when you crack an egg, the egg is runny and liquidity.  The answer is that an egg actually has two membranes that stick together to look like one and then the egg shell is on top of that!  <The science: these semi-permissible layers are called the "outer shell membrane" and the "inner shell membrane" - very creative names - and they are made partly of keratin (the same as your fingernails!) >

Experimentation

Next we colored the eggs by putting the eggs in water with food coloring. After a few minutes the egg turns the same color as the water.

 

Conversation Starters:

• Osmosis!  Talk about how the water traveled from the cup into the egg by using osmosis to get into the egg and since the water was colored - when the water went into the egg, it turn the egg the same color as the water!
• Older kids : talk about how the egg is composed of 90% water and so when it is placed in a cup filled with 100% water - it wants to find its equilibrium meaning it wants to be the same inside the egg and outside the egg.  So that is why water travels into the egg via osmosis.

 

Ending

So - now what should you do with the naked egg...

• Some kids couldn't wait to smash it!  When you break the membrane you get a vinegary runny egg and a membrane in your hard!
• Some kids (mine!) wanted to take the egg home and let it sit for a few days outside of vinegar.  Then the egg becomes more like rubber and can be dropped and "bounced" a few inches off the ground. 
• You can also let it sit in the colored water overnight
• Or - you can soak in in corn syrup overnight to get a dehydrated egg!