The Planets Song

Solar System (Chinese)

 

 

 

Experiment 4

Design and Test a Parachute

Learn about air resistance while making an awesome parachute! Design one that can fall slowly to the ground before putting it to the test, making modifications as you go.

What you'll need:

• A plastic bag or light material
• Scissors
• String
• A small object to act as the weight, a little action figure would be perfect

Instructions:

1.     Cut out a large square from your plastic bag or material.

2.     Trim the edges so it looks like an octagon (an eight sided shape).

3.     Cut a small whole near the edge of each side.

4.     Attach 8 pieces of string of the same length to each of the holes.

5.     Tie the pieces of string to the object you are using as a weight.

6.     Use a chair or find a high spot to drop your parachute and test how well it worked, remember that you want it to drop as slow as possible.

What's happening?

Hopefully your parachute will descend slowly to the ground, giving your weight a comfortable landing. When you release the parachute the weight pulls down on the strings and opens up a large surface area of material that uses air resistance to slow it down. The larger the surface area the more air resistance and the slower the parachute will drop.

Cutting a small hole in the middle of the parachute will allow air to slowly pass through it rather than spilling out over one side, this should help the parachute fall straighter.

Experiment 3

Make an Egg Float in Salt Water

An egg sinks to the bottom if you drop it into a glass of ordinary drinking water but what happens if you add salt? The results are very interesting and can teach you some fun facts about density.

What you'll need:

• One egg
• Water
• Salt
• A tall drinking glass

Instructions:

1.     Pour water into the glass until it is about half full.

2.     Stir in lots of salt (about 6 tablespoons).

3.     Carefully pour in plain water until the glass is nearly full (be careful to not disturb or mix the salty water with the plain water).

4.     Gently lower the egg into the water and watch what happens.

What's happening?

Salt water is denser than ordinary tap water, the denser the liquid the easier it is for an object to float in it. When you lower the egg into the liquid it drops through the normal tap water until it reaches the salty water, at this point the water is dense enough for the egg to float. If you were careful when you added the tap water to the salt water, they will not have mixed, enabling the egg to amazingly float in the middle of the glass.

Solar System

 

 

 

 

What Is The Solar System?

The Solar System is made up of all the planets that orbit our Sun. In addition to planets, the Solar System also consists of moons, comets, asteroids, minor planets, and dust and gas.

Everything in the Solar System orbits or revolves around the Sun. The Sun contains around 98% of all the material in the Solar System. The larger an object is, the more gravity it has. Because the Sun is so large, its powerful gravity attracts all the other objects in the Solar System towards it. At the same time, these objects, which are moving very rapidly, try to fly away from the Sun, outward into the emptiness of outer space. The result of the planets trying to fly away, at the same time that the Sun is trying to pull them inward is that they become trapped half-way in between. Balanced between flying towards the Sun, and escaping into space, they spend eternity orbiting around their parent star.


 



Experiment 2

Invisible Ink with Lemon Juice

Making invisible ink is a lot of fun, you can pretend you are a secret agent as you keep all your secret codes and messages hidden from others. All you need is some basic household objects and the hidden power of lemon juice.

What you'll need:

• Half a lemon
• Water
• Spoon
• Bowl
• Cotton bud
• White paper
• Lamp or other light bulb

Instructions:

1.     Squeeze some lemon juice into the bowl and add a few drops of water.

2.     Mix the water and lemon juice with the spoon.

3.     Dip the cotton bud into the mixture and write a message onto the white paper.

4.     Wait for the juice to dry so it becomes completely invisible.

5.     When you are ready to read your secret message or show it to someone else, heat the paper by holding it close to a light bulb.

What's happening?

Lemon juice is an organic substance that oxidizes and turns brown when heated. Diluting the lemon juice in water makes it very hard to notice when you apply it the paper, no one will be aware of its presence until it is heated and the secret message is revealed. Other substances which work in the same way include orange juice, honey, milk, onion juice, vinegar and wine. Invisible ink can also be made using chemical reactions or by viewing certain liquids under ultraviolet (UV) light.

Experiment 1

Experience Gravity Free Water

What goes up must come down right? Well try bending the rules a little with a cup of water that stays inside the glass when held upside down. You'll need the help of some cardboard and a little bit of air pressure

What you'll need:

• A glass filled right to the top with water
• A piece of cardboard

Instructions:

1.     Put the cardboard over the mouth of the glass, making sure that no air bubbles enter the glass as you hold onto the cardboard.

2.     Turn the glass upside down (over a sink or outside until you get good).

3.     Take away your hand holding the cardboard.

What's happening?

If all goes to plan then the cardboard and water should stay put. Even though the cup of water is upside down the water stays in place, defying gravity! So why is this happening? With no air inside the glass, the air pressure from outside the glass is greater than the pressure of the water inside the glass. The extra air pressure manages to hold the cardboard in place, keeping you dry and your water where it should be, inside the glass.

Buku Rujukan

Nota Sains Tahun 4 - 6