Sunday 6 May 2018

8.2. Sources of energy





1. NON-RENEWABLE
Non-renewable energy comes from sources that will run out or will not be replenished in our lifetimes—or even in many, many lifetimes. Most non-renewable energy sources are fossil fuels: coal, petroleum, and natural gas.

Nonrenewable resources are those found inside the earth, and they took millions of years to form. Today, close to 84% of the total amount of energy used globally comes from fossil fuels.


Advantages and Disadvantages
Fossil fuels are a valuable source of energy. They are relatively inexpensive to extract. They can also be stored, piped, or shipped anywhere in the world.
However, burning fossil fuels is harmful for the environment. When coal and oil are burned, they release particles that can pollute the air, water, and land. Some of these particles are caught and set aside, but many of them are released into the air.

2. RENEWABLE ENERGY SOURCES
Renewable energy is energy that is collected from renewable resources, which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves, and geothermal heat.






8.1. Forms of energy




Forms of energy:

  • Many forms of energy exist, but they all fall into two basic categories:
  • - Potential energy
  • - Kinetic energy



UNIT 8: ENERGY

WHAT ARE WE GOING TO LEARN?
- What energy is
- Forms of energy
- Energy sources: renewable and non-renewable
- Electricity and magnetism

WHAT IS ENERGY?


DEFINITION: Energy is the ability to do work.
People use energy for everything from making a jump shot to sending astronauts into space. There are two types of energy:

  1. Stored (potential) energy
  1. Working (kinetic) energy

For example, the food a person eats contains chemical energy, and a person's body stores this energy until he or she uses it as kinetic energy during work or play.




Friday 20 April 2018

7.4. Classifying matter

Matter is all around us. As you have learned, depending on its state, we classify it into solids, liquids and gases.
We can classify it further depending on wether it is one type of matter or a combination of different kinds of matter.


Matter can be either a pure substance or a mixture.
- Pure substances are made up of only one type of matter.
- Mixtures are made up of two or more pure substances (two or more types of matter).

Sunday 8 April 2018

UNIT 7: Matter and forces

What are we going to learn?

- What matter is
- The states of matter
- Changes in the states of matter
- Physical and chemical changes of matter
- Properties of matter


7.1. What is matter?



Tuesday 13 February 2018

5.4. Aquatic Ecosystems





Types of Freshwater Biomes
There are three main types of freshwater biomes: 
  • ponds and lakes
  • streams and rivers
  • wetlands
Ponds and Lakes 
Ponds and lakes are often called lentic ecosystems. This means that they have still or standing waters, not moving like rivers or streams.

Lake animals
Animals include plankton, crayfish, snails, worms, frogs, turtles, insects, and fishes. 

Lake plants - Plants include water lilies, duckweed, cattail, bulrush, stonewort, and bladderwort. 

Streams and rivers 
Rivers and streams are often called lotic ecosystems. This means that they have flowing waters, unlike the still waters of ponds and lakes. This biome can vary in size dramatically from small trickling streams to mile wide rivers that travel for thousands of miles. 

Key factors influencing the ecology of streams and rivers include: 
  • Flow - the amount of water and the strength at which it flows will impact the types of plants and animals that can live in a river. 
  • Light - light has an impact because it provides energy to plants through photosynthesis. The amount of light due to seasons or other factors will impact the river's ecosystem. Temperature - The climate of the land the river is flowing through will have an impact on the local plant and animal life. 
  • Chemistry - this has to do with the type of geology that the river is flowing through. It impacts what type of soil, rocks, and nutrients are in the river. 

River animals
Animals that live in or around the river include insects, snails, crabs, fishes such as salmon and catfish, salamanders, snakes, crocodiles, otters, and beavers. 

River plants
Plants that grow around rivers vary greatly depending on the location of the river in the world. The plants typically live along the edge of the river where the water is moving slower. Plants include tapegrass, water stargrass, willow trees, and river birch. 

Wetlands Biome 
The wetlands biome is a combination of land and water. It can be thought of as land that is saturated with water. The land may be mostly underwater for part of the year or just flooded at certain times. 
They are often located near large bodies of water like lakes and rivers and can be found throughout the world. Wetlands can play an important role in nature. When located near rivers, wetlands can help to prevent flooding. They also help to purify and filter water. 

Wetland animals
Wetlands have a huge diversity in animal life. Amphibians, birds, and reptiles all do well in the wetlands. The largest predators are alligators and crocodiles. Other animals include beavers, raccoons, and deer.
Wetland plants - Wetland plants may grow entirely underwater or float on top of the water. Other plants grow mostly out of the water, like large trees. Plants include milkweed, water lilies, duckweed, cypress trees, and mangroves. 


Nelson, Ken. (2018). Science for Kids: Freshwater Biome. Ducksters. Retrieved from http://www.ducksters.com/science/ecosystems/freshwater_biome.php 


QUIZ
1. The freshwater biome has a lower content of ______ than the marine biome? 
a. Sulfur
b. Plants
c. Fish
d. Salt
e. Mammals

2. Which of the following is not a part of the freshwater biome? 
a. Ponds
b. Lakes
c. Rivers
d. Wetlands
e. Oceans

3. What type of freshwater biome is sometimes called a lentic ecosystem? 
a. Lake
b. River
c. Stream
d. Tributary
e. Brook


4. Which of the following would be considered a lotic ecosystem? 
a. Lake
b. River
c. Pond
d. Pool
e. Ocean

5. Which of the following will have an impact on the ecology of streams and rivers? 
a. Flow
b. Light
c. Temperature
d. Chemistry
e. All of the above

6. Which of the following will vary depending on the type of geology that a river flows through? 
a. Flow
b. Light
c. Temperature
d. Chemistry
e. All of the above

7. What type of freshwater biome is a combination of land and water? 
a. Ponds
b. Lakes
c. Rivers
d. Wetlands
e. Oceans

Types of Marine Biomes 

Oceans - These are the five major oceans that cover the world including the Atlantic, Pacific, Indian, Arctic, and Southern Oceans. 
Coral reefs - Coral reefs are small in size when compared to the oceans, but around 25% of marine species live in the coral reefs making them an important biome. 
Estuaries - Estuaries are areas where rivers and streams flow into the ocean. This area where freshwater and saltwater meets, creates an ecosystem or biome all its own with interesting and diverse plant and animal life.

Animals of the Marine Biome
The marine biome has the most biodiversity of all the biomes. Many of the animals, such as fish, have gills that allow them to breathe the water. Other animals are mammals that need to come to surface to breathe, but spend much of their lives in the water. Another type of marine animal is the mollusk which has a soft body and no backbone. 
Here are just a few of the animals that you will find in the marine biome: Fish - Sharks, swordfish, tuna, clown fish, grouper, stingray, flatfish, eels, rockfish, seahorse, sunfish mola, and gars. Marine mammals - Blue whales, seals, walruses, dolphins, manatees, and otters. Mollusks - Octopus, cuttlefish, clams, conch, squids, oysters, slugs, and snails.

Plants of the Marine Biome 
There are thousands of species of plants that live in the ocean. They rely on photosynthesis from the sun for energy. Plants in the ocean are extremely important to all life on planet earth. Algae in the ocean absorbs carbon dioxide and provides much of the Earth's oxygen. Examples of algae include kelp and phytoplankton. Other ocean plants are seaweeds, sea grasses, and mangroves

Nelson, Ken. (2018). Science for Kids: Marine or Ocean Biome. Ducksters. Retrieved from http://www.ducksters.com/science/ecosystems/marine_biome.php