Compare and Contrast

Compare and Contrast

(same and different)  

A. Understanding of compare and contrast

Compare  = Explain the same of two or more things. 

Example:

• They are so beatiful.
•  The toddlers have been playing a ball for an hour.

Contrast  = Explain the difference of two or more things.

Example:   

•   The distance from my house to Shinta's house is very far away.    

            The distance from my house to Shinta's house is very close. 

•   This room is very dark.  

            This room is very bright.

B. Compare and contrast Hidrogen and Helium 

1. Hidrogen

Hidrogen is a chemical element in the periodic table that has the symbol H. Has atomic number 1 and mass number 1. Hidrogen belongs to group IA (alkaline group), which is not metal. Hidrogen also has an oxidation rate 1. At standard temperature and pressure, hidrogen is a gas that is colorless, odorless, and tasteless.

hidrogen is highly flammable and burns with invisible fire. Hydrogen will cause burns when it comes in contact with oxygen.The reaction product of hidrogen and oxygen is water or H2O. Hidrogen gas consists of diatomic molecules shown with the symbol H2.The most common place to find hydrogen on earth is water. Hidrogen is mostly found in stars and planets.

British scientist Henry Cavendish discovered hydrogen as an element in 1766. Cavendish experimented with zinc and hydrochloric acid. He discovered hidrogen and also discovered that zinc and hydrochloric acid produce water when burned.

2. Helium

Helium is a chemical element in the periodic table that has the He symbol. Has atomic number 2 and mass number 4,00260. Helium belongs to the group VlllA (noble gas), which is not metal. Helium also has an oxidation rate of 1.

At room temperature helium is odorless, tasteless, and is a colorless gas. It has a very low boiling and melting point, which means that helium is commonly found in the gas phase except under the most extreme conditions. Helium is the only element that is not solid under ordinary pressure and remains liquid even at zero point. Helium is either an inert or noble gas. Means that its outer shell is full of electrons. This makes it extremely unreactive and non-flammable.

Helium is quite rare on Earth. There is very little in the atmosphere of the earth because it is so light that it eventually escapes into space. Helium is used in balloons and air balloons to make them float. It is not shaped like light on hydrogen, but the gas is much safer than the highly flammable hydrogen. Helium was first discovered in 1868 by astronomer Pierre Janssen. He saw a new element when studying the solar eclipse. This element was not found on Earth until 1895.

C. Double Buble Map