FIREPROOF BALLOONS

Balloons are rather fragile things. You know that they must be kept away from sharp objects. The also need to be kept away from flames. A fire can weaken the rubber and cause it to burst. However, in this experiment you will find out how you can hold a balloon directly in a flame without breaking the balloon.

For this experiment you will need:

• two round balloons, not inflated
• several matches
• water

Inflate one of the balloons and tie it closed. Place 60 milliliters (¼ cup) of water in the other balloon, and then inflate it and tie it shut.

Light a match and hold it under the first balloon. Allow the flame to touch the balloon. What happens? The balloon breaks, perhaps even before the flame touches it.

Light another match. Hold it directly under the water in the second balloon. Allow the flame to touch the balloon. What happens with this balloon? The balloon doesn't break. You may even see a black patch of soot form on the outside of the balloon above the flame.

Why does the balloon with no water break in the flame? The flame heats whatever is placed in it. It heats the rubber of both balloons. The rubber of the balloon without water becomes so hot, that it becomes too weak to resist the pressure of the air inside the balloon.

How does the balloon with water in it resist breaking in the flame? When water inside the balloon is placed in the flame, the water absorbs most of the heat from the flame. Then, the rubber of the balloon does not become very hot. Because the rubber does not become hot, it does not weaken, and the balloon does not break.

Water is a particularly good absorber of heat. It takes a lot of heat to change the temperature of water. It takes ten times as much heat to raise the temperature of 1 gram of water by 1C than it does to raise the temperature of 1 gram of iron by the same amount. This is why it takes so long to bring a teakettle of water to the boil. On the other hand, when water cools, it releases a great deal of heat. This is why areas near oceans or other large bodies of water do not get as cold in winter as areas at the same latitude further inland.

RAINBOW IN A GLASS

You will need the following materials:

• four different colors of food coloring (e.g. red, yellow, green, blue)
• five tall glasses or clear plastic cups
• ¾ cup (180 g) of granulated sugar
• a tablespoon for measuring
• 1 cup (240 ml) water

In the first glass, add one tablespoon (15 g) of sugar. In the second glass, add two tablespoons of sugar, three in the third glass, and four in the last glass. Then add three tablespoons (45 ml) of water to each glass, and stir until the sugar is dissolved. If the sugar in any of the glasses will not dissolve, add one more tablespoon (15 ml) of water to all of the glasses, and stir again. When the sugar is completely dissolved, add two or three drops of red food coloring to the first glass, yellow to the second, green to the third, and blue to the last glass.

In the remaining glass we will create our rainbow. Fill the glass about a fourth of the way with the blue sugar solution. Next, carefully add the green solution to the glass. Do this by putting a spoon in the glass, just above the level of the blue solution. Slowly pour the green solution into the spoon, raising the spoon to keep it just above the level of the liquid, until the glass is half full. Add the yellow solution, and then the red one in the same manner. What do you notice about the colored solutions?

The amount of sugar dissolved in a liquid affects its density. The blue solution has the most sugar dissolved in it and is therefore the densest. The other solutions are less dense than the blue solution, so they float on top of it. The densities of the solutions should be very close however, and the solutions are miscible, so you will see that the layers do not form well defined boundaries as in the first experiment. If done carefully enough, the colors should stay relatively separate from each other. What do you think will happen if you stir up the liquids in the glass?

DOMINANT SIDE OF THE BODY

What you'll need: A pen or pencil Paper or a notepad to write your findings on An empty tube (an old paper towel tube is good) A cup of water A small ball (or something soft you can throw) Instructions: Write ‘left’ or ‘right’ next to each task depending on what side you            used/favored. When you’ve finished all the challenges review your results and make            your own conclusions about which is your dominant eye, hand and            foot. Eye tests: Which eye do you use to wink? Which eye do you use to look through the empty tube? Extend your arms in front of your body. Make a triangle shape using your fore              fingers and thumbs. Bring your hands together, making the triangle smaller             (about the size of a coin is good). Find a small object in the room and focus on             it through the hole in your hands (using both eyes). Try closing just your left            eye and then just your right, if your view of the object changed when you            closed your left eye mark down ‘left’, if it changed when you closed your right            eye mark down ‘right’. Hand/Arm tests: Which hand do you use to write? Pick up the cup of water, which hand did you use? Throw the ball, which arm did you use? Foot/Leg tests: Run forward and jump off one leg, which did you jump off? Drop the ball on the ground and kick it, which foot did you use? What's happening? So what side do you favor? Are you left handed or right handed? Left footed or  right footed? Is your right eye dominant or is it your left? Around 90% of the world’s population is right handed. Why most people favor the  right side is not completely understood by scientists. Some think that the reason is  related to which side of your brain you use for language. The right side of your  body is controlled by the left side of your brain, and in around 90% of people the  left side of the brain also controls language. Others think the reason might have more to do with culture. The word ‘right’ is  associated being correct and doing the right thing while the word ‘left’ originally  meant ‘weak’. Favoring the right hand may have become a social development as  more children were taught important skills by right handed people and various tools  were designed to be used with the right hand. Around 80% of people are right footed and 70% favor their right eye. These  percentages are lower than those who are right handed and this could be because  your body has more freedom of choice in choosing its favored foot and eye than that  of its favored hand. In other words you are more likely to be trained to use your right  hand than your right foot and even more so than your right eye. It’s not strange to  find people who favor the opposite hand and foot (e.g. left hand and right foot), and  some people are lucky enough to be ambidextrous, meaning they can use their left  and right sides with equal skill. Try testing others and coming to your on conclusions about what side the human  body favors and why. Extra: Are you more likely to be left handed if one of your parents is left handed?  What are some of the possible disadvantages for left handed people? (Tools, writing  materials etc) Do left handed people have an advantage in sports? Interesting fact: In 2009, only 7% of the players in the NBA were left handed while in  2008 around 26% of MLB pitchers were left handed. Is it better to be left handed in some sports than others? What do you think?

COLOR SYMPHONY

A flat tray (like a cookie baking tray) Food coloring (at least 3 different colors) Whole milk - low fat milk will not work for this experiment Liquid soap used for washing dishes Pour the milk into the tray so that it just covers the bottom Add about 6-8 drops of different colored food coloring            onto the milk in different spots Add about 5 drops of the liquid soap onto the drops of            food coloring and watch the show! To clean up, simply pour the colored milk down the            drain. (don't drink it!) So you know where the color comes from, but why milk and liquid  soap? The main job of dish soap it to go after fat and break it down.  Usually the fat is on dishes from the food we eat, but fat is also in  whole milk. When you drop the liquid soap onto the tray, it tried to  break down the fat in the milk. While it was doing that, it caused the  colors to scatter and mix creating a very colorful display. Have fun!    The project above is a DEMONSTRATION. To make it a true   experiment, you can try to answer these questions: 1. What liquid dish soap works the best? 2. Does the shape of the tray affect the reaction?