Fireproof Balloon: Difference between revisions

From Science Theatre
Jump to navigation Jump to search
imported>Stwikiadmin
Created page with "== Age == Elementary School == Format == Stage Show == Materials == Two round balloons Several matches Water == Safety Precautions == Science Theatre demonstr..."
imported>Stwikiadmin
No edit summary
 
(One intermediate revision by the same user not shown)
Line 1: Line 1:
== Age ==
{| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right"
| [[Chemistry]], [[Physics]]:
| Heat Capacity
|-
| Grade Range:
| [[Elementary School]]
|-
| Format:
| [[Hands-on]], [[Stage]]
|}


Elementary School
This demonstration
 
== Format ==
 
Stage Show


== Materials ==
== Materials ==


    Two round balloons
* Matches
    Several matches
* Water
    Water
* Balloons


== Safety Precautions ==
== Safety Precautions ==


Science Theatre demonstrators must keep the safety of themselves and their audience in mind at all times. All Science Theatre demonstrators must have read through the Safety Training page. The ST Safety Box with first aid kit, fire extinguisher, etc. should always be available to demonstrators. Always wear safety gloves, glasses, and a labcoat if handling chemicals; always perform potentially dangerous demonstrations at a safe distance from the audience; and always keep a very close eye on any volunteers you call from the audience. be careful when handling matches to avoid burning yourself or causing accidental fires.
Please read the Fire Safety section of the [[Demonstration Safety]] page before performing this demonstration.
 
== Preparation ==
 
Inflate one of the balloons and tie it closed. Place 60 milliliters (1/4 cup) of the water in the other balloon, and then inflate it and tie it shut.


== Demonstration ==
== Demonstration ==


Light a match and hold it under the first balloon. Allow the flame to touch the balloon. What happened? The balloon breaks, perhaps even before the flame touches it.
# Blow up a balloon and tie it off. Add 1/4 cup of water into a second balloon before blowing it up to the same size, and tie it off.
 
# Show the first balloon to the audience and ask them what will happen if you held a lit match under it. After one or two responses, light a match and hold it under the balloon. It will pop!
Light another match. Hold it directly under the water in the second balloon. Allow the flame to touch the balloon. What happens to the 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.
# Now mention that the second balloon has some water in it. Do they think the water will make a difference? Light a match and hold it under the balloon where the water is at. The match will burn out, and the balloon will be OK!
 
== What to Say ==
 
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.


== Why It Is ==
== Why This Works ==


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 boil. On the other hand, when water cools, it releases a great deal of heat.
When we hold the first balloon over the match, it pops because of the heat. The rubber of the balloon wasn't able to handle the heat, and the air inside the balloon was expanding as it got warmer. These two things resulted in the balloon popping, since neither the rubber or the air could handle a lot of heat. The second balloon had a little water inside of it, which protected it from popping. Water has a high ''Heat Capacity'', meaning that water is able to absorb a lot of heat without having a high increase in temperature. When the balloon is being heated, the water absorbs the heat from the rubber instead of letting the air heat up and expand. This protects the balloon from popping, even as soot gathers on the bottom of it! For a gallon of water, you would need nearly 4,000 calories (or 4 Calories) of heat to raise the temperature by only one degree Celsius. This is why "A watched pot never boils" is a common proverb; a pot of water needs a lot of energy to boil, so you will be watching it for a long time!


== Real Life Examples ==
== Additional Information ==


This is why areas near oceans or other large bodies of water do not get cold in the winter as areas at the same latitude further inland.
* This demonstration pairs well with the [[Nonburning Money]].

Latest revision as of 19:00, 24 June 2016

Chemistry, Physics: Heat Capacity
Grade Range: Elementary School
Format: Hands-on, Stage

This demonstration

Materials

  • Matches
  • Water
  • Balloons

Safety Precautions

Please read the Fire Safety section of the Demonstration Safety page before performing this demonstration.

Demonstration

  1. Blow up a balloon and tie it off. Add 1/4 cup of water into a second balloon before blowing it up to the same size, and tie it off.
  2. Show the first balloon to the audience and ask them what will happen if you held a lit match under it. After one or two responses, light a match and hold it under the balloon. It will pop!
  3. Now mention that the second balloon has some water in it. Do they think the water will make a difference? Light a match and hold it under the balloon where the water is at. The match will burn out, and the balloon will be OK!

Why This Works

When we hold the first balloon over the match, it pops because of the heat. The rubber of the balloon wasn't able to handle the heat, and the air inside the balloon was expanding as it got warmer. These two things resulted in the balloon popping, since neither the rubber or the air could handle a lot of heat. The second balloon had a little water inside of it, which protected it from popping. Water has a high Heat Capacity, meaning that water is able to absorb a lot of heat without having a high increase in temperature. When the balloon is being heated, the water absorbs the heat from the rubber instead of letting the air heat up and expand. This protects the balloon from popping, even as soot gathers on the bottom of it! For a gallon of water, you would need nearly 4,000 calories (or 4 Calories) of heat to raise the temperature by only one degree Celsius. This is why "A watched pot never boils" is a common proverb; a pot of water needs a lot of energy to boil, so you will be watching it for a long time!

Additional Information