Archive for the ‘science’ Category
Energy gives us the ability to do all kinds of things such as; write, walk, read and cook. There are eight different energies sorted into two groups which are Working Energy and Stored Energy. Below are different types of Working Energy:
Here is the list of Stored Energy:
Potential Energy – An object has potential energy depending on its position and condition, for example:
A ball has potential energy when it balances on top of another ball because of its position.
A rubber band has potential energy when it is stretched because of its condition.
Heat Energy – Heat energy heats an object, with a cooler temperature, making it hot. Here are some examples of situations when objects release heat energy:
A pot filled with water is placed on a gas stove which had been turned on. The fire on the gas stove releases heat energy making the water in the pot boil after a few minutes.
When we rub our hands rapidly, heat energy will be released during this process, making our hands hot.
Heat Energy sometimes comes with light energy.
Light Energy – Light energy is released by things that give out light. Without light energy, we will not be able to see our surroundings. Examples of situations that give out light energy are listed below:
By turning on a torch, light energy will be released, allowing us to see around us.
If you light up a fire, light energy is released together with heat energy.
Electrical Energy – Electrical energy is the energy used to work an electrical circuit, for example:
When two pieces of wires are connected to a bulb and a battery, the battery will release electrical energy which would flow through the wires lighting up the bulb.
Kinetic Energy – Kinetic energy is the energy absorbed by moving objects. For example:
If we roll a ball across the floor, the ball will absorb kinetic energy as it goes.
A car moving down a hill absorbs kinetic energy as it goes down
When an object moves faster, more kinetic energy will be absorbed into the object. Here are some examples:
Two balls with the same size and weight were pushed. One ball was rolling faster than the other. The fast rolling ball absorbs more kinetic energy than the ball with a slower speed.
Two leaves were blown in the wind. Both leaves are at the same shape and size. One of it was floating faster than the other leaf. The leaf that was flying faster absorbs more kinetic energy.
When two things, with different sizes move together at the same speed, the larger object will absorb more kinetic energy. Below are some examples:
Two toy cars with different sizes were pushed across a table at the same time and speed. The larger car will absorb more kinetic energy than the smaller car.
When two different sized trolleys were pushed together at the same speed. The smaller trolley will absorb less kinetic energy than the larger trolley.
Sound Energy – Sound energy travels in a form of waves. Sound energy is released when a sound is made. Some examples are shown below:
When a piano is played, sound energy is released as music filled the air.
If you tap a table, tapping sound will be heard which means, sound energy is released every time the table is tapped.
When something vibrates, a sound is made and sound energy will be released for example,
If a piece of string is pulled tightly and plucked at the center, the string will vibrate making a sound. This shows that sound energy is released.
Chemical Energy – As a stored energy, Chemical energy are the energy that is stored inside something to be changed into other energies. The following list shows some examples of things that contains chemical energy:
Food contains chemical energy. For your body to move around, it uses the chemical energy from the food.
Batteries contain chemical energy. This stored energy will soon be used as electrical energy to work a circuit.
Nuclear Energy – Nuclear energy is released by elements like Uranium and Hydrogen. These element can release a lot of energy. Nuclear energy are released in many forms. One of the many forms is, Radioactive Rays. As air pollutants, Radioactive Rays may cause very serious illness.
Energies cannot be produced or destroyed. Therefore, energies can change from one state to another. Here are some examples:
A toaster oven – Electrical energy –> Heat energy + Light energy
An alarm clock – Chemical energy –> Kinetic energy + Sound energy
There are at least six sources of energy. The sources are listed below:
Solar – Solar panels are used to change heat to other energies for example, electrical energy.
Wind – Wind turbines are used to change kinetic energy to other energies.
Wave – Dams are usually used to change kinetic energy, from the waves, into electrical energy. Since hydro means water this type of electricity is also called as hydroelectricity.
Biomass – Biomass is the energy source from organic materials.
Geothermal – Geo is earth and Thermal means heat. Geothermal is the heat from deep inside the earth. Geothermal works by letting the steam from the heat turn a wind turbine in the factory.
Fossils – Fossils are made of the remains of dead plants and animal that died years ago. These energy sources are pressed under layers of soil for thousands of years.
These sources of energy are sorted into two groups called, Renewable Energy Sources and Non-Renewable Energy Sources. Renewable energy sources are sources of energy that can be renewed. Non-renewable sources of energy are energy sources that will be used up one day and cannot be renewed. Below are the lists of both categories.
Renewable Energy Sources:
Non-Renewable Energy Sources
Cells are the smallest living unit in our body. We can only see it through a microscope.
There are two types of cells, animal cells and plant cells. Both of them are made up of:
- Cell membrane
- Protoplasm (nucleus plus cytoplasm)
Three additional parts are only available in plant cells. They are:
- Cell wall
Their Physical Properties are:
The function of these parts are:
Below are the differences and similarities between both types of cells:
Unicellular organisms are living things that only have one cell. On the other hand, multicellular organisms have lots of cells. Here are some examples of unicellular and multicellular organisms:
Forming an organism
A tissue is a group of cell that does similar work. Each organs are made of different types of tissues. Some example of organs are:
Different organs with different functions work together to complete one system. Here are some examples of systems:
And these systems form an organism by working together.
The above explains how lots of cells share their work to form an multicellular organism and it is called the cell organisation. The chart below shows the cell organisation:
However a unicellular organism has to do all of the work by itself. The cell does everything to keep the organism alive and healthy from respirating and digesting to excreting waste materials.
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Recently, my family and I went to Pusat Sains Negara (National Science Center) to see the Dinosaurs Exibition.
Over there, I saw all kinds of dinosaurs, for example T-Rex, Stegosaurus and lots more. The dinosaurs swing their huge heads and tails from side to side. The big dinosaurs make surprising loud noises and the cute small ones make cute little screechy sounds. There is one that makes a cute sound like Primiligh or her kittens.
We had a great time there and I hope so will you if you visit the Pusat Sains Negara 🙂 It is a fun place to visit.
Food chain is used to show the food relationship between plants and other animals . A few food chain can construct a food web.
- grass -> deer -> cobra -> tiger
- grass -> deer -> tiger
- grass -> grasshopper -> frog -> cobra -> tiger
From the above food chain transform to afood chain:
Food chain always start with green plants. The piramid of numbers shows the number of producer and consumers.
A producer is a green plant because green plant can make their own food and the process is called photosynthesis.
Consumers are animals that consume other animals and plants.There are three consumers and they are:
- Primary consumer – herbivore or omnivore
- Secondary consumer – carnivore or omnivore
- Tertiary consumer – carnivore or omnivore
- Herbivores are animals that eat only plants.
- Carnivores are animals that eat only other animals.
- Omnivores are animals that eat other animals and plants.
Animals need to reproduce to prevent their species from extinction. Animals reproduce by laying eggs or giving birth. Different animals have their own ways to ensure the survival of their species.
Animals that give birth to their young nurture and care for their babies. Their mothers suckle their young and have their own ways to protect their young from danger.
- Cow – Protect it’s young with its horn
- Cat – Fight attackers with its claws and move their kittens to a safer place if the kittens are disturbed.
- Kangaroo – Carries its young in its pouch wherever it goes.
- Zebra, elephant and giraffe – stays in group for a better defense
- Whale and dolphin – Stays close to its calves
- Leopard – Attacks its enemies with sharp teeth and claws
Not all animals that lay eggs take care of their eggs and young. This is what a typical bird will do to ensure the safety of its eggs and young:
- Build a good nest in a safe spot
- Incubate their eggs after they lay them
- Feed their young when they hatch
- Protect their young from predators
These are some animals that lay eggs and how they ensure the survival of their eggs and young.
- Turtle – Lays hundreds of eggs at night and buries them in the sand. Their eggs are protected by soft shells or skin
- Spider – Lays egg in a silk cocoon and carries the silk cocoon everywhere it goes
- Snake – Coils round the eggs and attacks animals that come close to the eggs
- Sea horse – The male sea horse use its pouch to store the eggs and looks after them until they hatch. It will protect the young until they can fend for themselves.
- Siamese fighting fish – The male fish catches the eggs in its mouth and drops them into a bubble nest that it has built. It also guards the nest and protects the babies.
- Crocodile – Lays eggs in the sand and stays nearby to guard the eggs. When the eggs hatch, it carries the baby crocodiles in the mouth to the river.
- Butterfly – Lays eggs on the underside of leaves.
- Frog – Lays large numbers of eggs with slimy and smelly coverings in the water. The covering prevents and discourages other animals from eating the eggs. The covering will be eaten by the tadpoles when they come out of the eggs.
- Fish – Lays lots of eggs close to water plants to hide them. Some fish keep their young in their mouth.
- Grasshoppers – Lays eggs in the soil.
- Snail – Lays about 60 – 100 eggs at night and buries them under stones.
- Scorpion – Carries its young on its back
- Cockroach – Lays egg protected by hard coverings and hides them in dark places.
- Housefly – Lays up to 500 eggs and hides them under rubbish or faeces.
Laying eggs on the underside of leaves or near rocks and waterplants helps to protect the eggs from being eaten. Laying lots of eggs ensure that some of the eggs have the chance to grow up into adult animals.
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If the seed/fruit disperse by water the fruit will fall off the tree and float on water.
The characteristics of these type of fruit are:
- Have a hard shell
- Able to float in the water
- Have water proof husk
A coconut is an example of seed/fruit that disperse by water
There are more ways how seeds disperse.
Microorganism are tiny living things. Micro means tiny and organism means living things. There are four types of microorganism with different sizes.