What is Global Warming?
Global warming refers to extreme changes in the Earth’s climate. The term illustrates dramatic increases in atmospheric and water temperatures experienced as a result of growing amounts of greenhouse gas emissions. Humans are responsible for producing these gases via cars, electricity, and factories. The main products of these activities that are to blame for global warming are methane and carbon dioxide; as carbon dioxide, methane, and chlorofluorocarbon compounds go farther and farther into the Earth’s atmosphere, they deplete the ozone layer.
Holes in the ozone are allowing harmful ultra violet rays (that are usually deflected by the ozone layer) to make their way to lower levels of the atmosphere. Greenhouse gases absorb and give off radiation from the UV rays, contributing to extreme temperature conditions.
For greater understanding of global warming and the greenhouse effect, check out:
Effects of Global Climate Change
Global warming has had extreme effects on the planet. Earth’s average surface temperature has been increasing; since the 1880s, temperature has increased by between 1 and 1.5 degrees Fahrenheit. While this may sound like a small number, it has heavily impacted other aspects of our global ecosystem, and it is continuing to rise at a faster rate. Arctic ice is vanishing and glaciers are melting; as a result, polar bears, penguins, and other animals have begun to suffer.
The recent frequency of heat waves, intense tropical storms, and natural disasters has also been partially attributed to trends in global climate change. Extreme weather will most likely have a negative impact on crops and agriculture. As staple crops become scarcer, they will become more expensive. Such products include rice, wheat, corn, and soy, which are also utilized in animal feed; the result: prices of many other types of food will increase as well, making all food relatively more expensive.
To read more about the effects of global warming, visit:
The Kyoto Protocol is an international effort to combat global climate change. Developed at the United Nations’ Convention on Climate Change in 1997, this treaty is aimed at capping the number of greenhouse gases emitted into the atmosphere and it intends to hold nations accountable to their environmental commitments. 191 countries have signed and ratified the treaty. The only country that has not ratified is the United States.
Perhaps the most well-known piece of legislation in the US is the Clean Air Act. The Clean Air Act was created to decrease the number of air pollutants being released into the atmosphere, subsequently having a positive impact on air quality and contributing to the general health of the population. Amendments have been made to the Clean Air Act over time to account for ozone depletion and acid rain. The US also utilizes regulations on fuel, energy, and water in order to help the environment.
For more information on these pieces of legislation:
Combating Global Warming—Being Green
In today’s society, the color green has become synonymous with environmental friendliness. Governments, businesses, and individuals can all contribute towards mitigating climate change, and in many cases, all of these groups have been working hard to become greener. Some towns use monetary incentives in order to motivate their citizens to become more environmentally conscious and friendly. The Federal Government also has incentives in place for businesses to encourage them to reduce their carbon footprints. On the other end of the environmental responsibility spectrum, the government uses taxes to discourage and penalize businesses that are particularly harmful to the environment.
Switching to renewable energy sources can help to protect the environment from damage that results from burning fossil fuels for energy. Scientific developments and the spread of wind, solar, and geothermal power are helping to make the world less carbon-dependent; they also help by producing less methane in the process of providing energy. On the whole, these sources of energy are more sustainable and less harmful to the planet. However, there are some sources of greenhouse gases that are harder for mankind to combat. Many animals emit methane from their bodies during food consumption and digestion-related processes.
To learn more about sustainable energy, you may want to read these sources:
“Carbon footprints” are used to measure the impact that certain individuals, products, and activities have on global warming. This metric attempts to quantify the amount of greenhouse gases that are being produced. Greenhouse gases are comprised of many elements and compounds, but Carbon Dioxide is often used as a proxy for these elements in calculations and discussions related to carbon footprints.
Almost every activity that occurs in the course of a single day has some impact on the environment. Transportation, electricity, and manufacturing are often highly detrimental and are major areas where people, businesses, and countries can cut down on their carbon footprints. Understanding the size of carbon footprints and what contributes to them allows each participant in the global environment to take action to reduce it.
More information about carbon footprints can be found by reading:
Phases of matter
Do you sometimes dump ice cubes into a drink to help keep cool on a hot summer day? Have you ever watched the ice cubes melt and wondered how you could make them melt more slowly—or even faster? In this science activity you will get to try some different, common household substances to try and answer this question: What will help a solid ice cube turn into a liquid puddle the fastest?
Temperature isn't the only thing that affects how a liquid freezes—and melts. If you've ever made homemade ice cream the old-fashioned way using a hand-crank machine, you probably know that you need ice and salt to freeze the cream mixture. Similarly, if you live in a cold climate, you've probably seen the trucks that salt and sand the streets after a snowfall to prevent ice from building up on the roads. In both of these instances salt is lowering the freezing point of water, which means that the water needs to be colder to turn from liquid into ice. For the ice cream maker, the temperature of the ice–salt mixture can get much lower than if just using normal ice, and this makes it possible to freeze the ice cream mixture. For the salt spread on streets, lowering the freezing point means that ice can melt even when the outdoor temperature is below water’s freezing point. Both of these events demonstrate “freezing point depression.”
Salt mixed with water is an example of a chemical solution. In a solution there is a solute (salt in this example) that gets dissolved in a solvent (water in this case). When other substances are mixed with water they may also lower its freezing point. In this science activity you'll investigate how salt, sand and sugar affect water's freezing point.
- Four ice cubes (They should all be the same size and shape.)
- Four drinking glasses (They should all be identical.)
- Table salt
- One-quarter teaspoon measuring spoon
- Prepare (or purchase) some ice cubes if you do not have any ready. They should all be the same size and shape.
- Into each drinking glass place one ice cube. Make sure the ice cube is oriented the same way in each glass. (Tip: If you are using ice cubes from a tray, it helps to let the tray sit at room temperature for about five minutes so that the ice cubes more easily come out of the tray cups and do not break into pieces.)
- Carefully sprinkle one-quarter teaspoon (tsp.) of salt over the ice cube in one drinking glass. Then sprinkle one-quarter tsp. of sugar over the cube in another glass and one-quarter tsp. of sand over the ice in the third. Do not sprinkle anything over the ice cube in the fourth glass. (It will be your control.) How do you think the salt, sugar and sand will affect how quickly the ice cubes melt?
- Set the drinking glasses aside somewhere indoors, out of direct sunlight.
- Watch the ice cubes over time, checking on them every five to 10 minutes. After around 30 minutes, which cube has melted the most? Which is the first one to melt completely? Which is the last?
- Overall, how do you think added salt, sugar or sand affects how quickly the ice melts? Can you explain why this might be?
- Extra: You could try this activity at different temperatures, such as in the refrigerator or outside on a hot day. How does adding salt, sugar or sand to the cubes affect how quickly they melt when exposed to a hotter or colder environment?
- Extra: In this activity you used one-quarter tsp. of each substance, but you could try adding more or less. Does the melting rate depend on the amount of the substance added?
- Extra: Identify some other substances to test on the ice cubes. Do other substances help melt the cubes more quickly or do they end up melting more slowly?
Observations and results
Did the ice cube sprinkled with table salt melt the fastest?
In this activity you tried adding salt, sugar or sand to ice to see whether the substance would help melt the ice. In other words, you wanted to test whether these substances could demonstrate freezing point depression, or the lowering of the ice's freezing point so that it melted into a liquid at a lower temperature than normal. You should have seen that the ice cube with salt sprinkled on it melted faster than any of the other cubes. This is because the amount by which the freezing point is lowered depends on the number of molecules dissolved, but not their chemical nature. (This is an example of what's called a "colligative property.") In the same volume there are more molecules of salt than there are of sugar or sand because the chemical components that make up the salt are much smaller than the sugar or sand.
Be sure not to pour the sand down a sink drain or garbage disposal! Instead, throw out the damp sand outside or in a trash can.
More to explore
Salt and Icy Roads, from Science Kids
How Does Salt Melt Ice and Snow?, from Highlights
What Makes Ice Melt Fastest?, from Science Buddies
Make Ice Cream in a Bag, from Science Buddies
This activity brought to you in partnership with Science Buddies