Animals on earth need a certain amount of heat to stay healthy and alive. How is it then, that animals like polar bars can survive in the arctic? How is it that whales can survive in the deep, freezing cold ocean? These animals have blubber, a layer of fat that acts as an insulator.
An insulator is a substance that prevents the transfer of heat or cold. The layer of blubber on a whale acts as a barrier to the cold of the ocean water. Because of its layer of blubber, the internal organs of the whale stay warm.
Your winter coat is an insulator. It keeps the cold in the winter air from making your body cold. It blocks the transfer of cold from the air to you. It also blocks the transfer of heat from your body to the air.
Here is an experiment that will show you how a simple insulator can make a big difference.
What You Need:
4 ziploc bags
Crisco Shortening or Vaseline
Fill a bowl with water and ice cubes. Put your hand inside one empty ziploc bag. Put that same hand with the bag on it inside a second ziploc bag. Now put your hand with the bags on it in the bowl of ice water. How long does it take for your hand to feel cold?
Ok, take your hand out of the bowl and take the bags off. Now fill one ziplic bag 1/2 full of Crisco or Vaseline. Put your hand inside one empty ziploc bag. Now put that same hand, with the bag on it, inside the bag full of Crisco or Vaseline. Squish the Crisco or Vaseline around so that it surrounds your hand. Now put your bag covered hand in the bowl of ice water. How long does it take for your hand to get cold?
The Crisco or Vaseline is an insulator, just like blubber. It stops the coldness of the ice water from transferring to your hand.
Words to Know: Insulator - A reduction of heat transfer between objects. Insulators keep cool things cool and warm things warm – like the thermos in your lunch box or the blubber on marine mammals. Heat – A high temperature. Blubber – A layer of fat that some animals have that helps keep the animals warm. Animals that have blubber include whales and sea lions, that live in the cold ocean and polar bears, that live in polar regions. Temperature – The level of heat present in a substance or of an object or person. Temperature is measured on a thermometer and expressed in number of degrees. Temperature can also be determined by using the sense of touch. Human skin is sensitive to changes in temperature.
Have an adult help you light a candle that can sit safely on a table. Blow up one balloon and tie it closed. Hold the balloon a couple inches from the candle flame. What happens? It pops, of course.
Now take the second balloon. Fill it with water. Don’t fill it with so much water it starts to expand. This is not going to be a water balloon. Now take the balloon with water in it and blow it up the rest of the way. Tie it closed. Hold this balloon a couple inches above the candle flame. Does it pop? How long does it take?
Balloons are made out of rubber. Rubber heats up really fast so the first balloon pops fast. Water molecules take a long time to heat up. The heat from the candle is soaked up by the water inside the second balloon so that balloon does not pop right away.
Science Experiment Idea: Try different temperatures of water in the balloon. If the water is warmer it seems like the balloon would pop faster. Test it out and see. Try ice water, room temperature water and hot tap water (NOT too hot to touch!). Make sure you use three balloons that are exactly the same. Measure the same amount of water into each balloon. Hold each balloon the same distance away from the candle flame. Remember that you only want ONE variable in an experiment. The variable is the one thing that changes, in this case the variable is the temperature of the water. Use a stopwatch to time how long it takes for the balloon to pop.
Here are some websites and books to help you understand and experiment with the fireproof balloon:
Pour 1/2 cup of milk into a large cup. Add 2 teaspoons vinegar. Mix. Place a coffee filter or paper towel over a second large cup. The coffee filter should sag a little bit to make a little filter bowl. Put a rubber band around the top of the cup so it holds the coffee filter in place. Now pour the milk/vinegar mixture into the filter bowl you made.
Let the liquid part of the mixture drip through the filter. This might take awhile. When the liquid is done dripping use a spoon to scrape the milky lumps off the coffee filter and into a bowl. Add 1/4 teaspoon baking soda to the lumps and mix. Is this substance getting sticky? Try it out – can you use it to glue two pieces of paper together?
When the milk and vinegar (an acid), mix together a chemical reaction takes place. A substance called Casein forms. Casein is a very long molecule that bends like plastic – that’s why the lumps of milk are pliable and bendy. When you add baking soda (a base) to the milk lumps another chemical reactionhappens turning the milk lumps into a sticky glue.
Science Experiment Idea: Make three batchs of milk glue, but make the variable (the thing you change) the amount of baking soda you add to the mixture. If you add 1/8 teaspoon baking soda to one batch, 1/4 teaspoon baking soda to one batch and 1/2 teaspoon baking soda to one batch, which one will be the most sticky? Why do you think so?
Here are some books and website that will help you make and understand glue made from milk:
Pour 1/2 cup of milk into a bowl. Put the bowl in the microwave for 1 minute. Check the bowl – if the milk looks lumpy you are done. If the milk does not look lumpy yet microwave it again for 25 seconds. Check it again. Repeat until the milk has formed lumps. After the lumps appear add 1 teaspoon vinegar to the bowl and let the bowl sit for 1 hour. After 1 hour is up pour the liquid off the milk lumps. Smash the lumps of milk together like play dough. You can make it any shape you want. If you leave it alone it will turn hard. If you want to save it keep it in a sealed container.
When the milk and vinegar (an acid), mix together a chemical reaction takes place. A substance called Casein forms. Casein is a very long molecule that bends like plastic – that’s why your lump of milk is pliable and bendy until it dries out and turns hard. Casein is also found in cheese…which is made from milk. Does this give you a clue as to how cheese is made?
Science Project Idea:
Make 3 different bowls of milk play dough. Use the same amount of milk in each bowl but use different amounts of vinegar in each one. OR use the same amount of vinegar in each bowl AND the same amount of milk…but use three different kinds of milk: skim, 2% and whole. Guess which bowl will make the best milk play dough. Why do you think so?
Here are some websites and books that will help you understand the science behind milk play dough:
A chemical reactionoccurs when substances are mixed together and are changed. Sometimes substances mix together and not much happens, at other times the results are pretty dramatic. Today we will look at a turbo charged chemical reaction. We will mix two substances together and add a catalyst, something to make the reaction happen faster.
What You Need:
Plastic Soda Bottle
Pour a cup of hydrogen peroxide in the liter soda bottle. Add a few drops of food coloring and a few drops of dish soap. In a separate bowl mix 1 teaspoon of yeast with two tablespoons of hot (not boiling – just use hot water from the faucet) water. Use the funnel to pour the yeast mixture into the mottle. Stand back!!
HINT: Do this one OUTSIDE!
HINT #2 If you want your geyser to spew more, use a plastic soda bottle that is smaller than a liter – a bottle that is smaller will have more foam shoot out of it.
Hydrogen peroxide has a lot of bubbles in it. If you let it sit long enough it will go “flat” – just like soda if you let it sit, the bubbles pop and eventually no carbination is left. When you add the yeast to the hydrogen peroxide the yeast makes this “going flat” happen super fast. The yeast breaks the hydrogen peroxide down into oxygen and water – a chemical reaction. The oxygen combines with the dish soap to make a whole lot of bubbles. In this experiment yeast is a catalyst. A catalyst speeds up a chemical reaction. Once the chemical reaction is over touch the foam – how does it feel? You might notice that the foam is a little bit warm. This chemical reaction is an exothermic one, that means that the chemical reaction produced a little heat.
Here are some websites and books that will give you more chemical reaction experiments to try:
Chemical Reaction – When a substances or substances is changed into a new substance. Exothermic – A chemical reaction that produces heat. Catalyst – Something that makes a chemical reaction happen faster.