Explanation

The burning of substances in air or oxygen on heating, with the release of a large amount of heat energy and light energy, is called combustion

while

In conduction, heat transfer occurs between objects by direct contact.

In convection, the heat transfer takes within the fluid

Condensation is the process by which water vapor in the air is changed into liquid water; it's the opposite of evaporation

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ND22-1-2023

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RY24012023

Explanation

When light shines on a photovoltaic (PV) cell – also called a solar cell – that light may be reflected, absorbed, or pass right through the cell.

The PV cell is composed of semiconductor material; the “semi” means that it can conduct electricity better than an insulator but not as well as a good conductor like a metal.

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RY24012023

Explanation

When Galileo pointed his telescope at Jupiter, the largest planet in our solar system, he made a startling discovery.

The planet had four "stars" surrounding it.

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RY24012023

Explanation

When water cools from 4°C to 0°C, ice crystals begin to form 

When water freezes, the water molecules form a lattice that increases the volume.

As a result, the density decreases

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ND22-1-2023

Explanation

The Milky Way is the galaxy that contains our solar system

It consists of 100–400 billion stars

The Milky Way is a huge collection of: 

• stars
• dust
• gas

It is visible as a hazy band of white light

Additional Information

The nearest galaxy to our Milky Way is Andromeda

Largest galaxy in the Universe is a Spiral galaxy 

Explanation

Inclined planes are used to move heavy loads over vertical obstacles.

The inclined plane is one of the six classical simple machines defined by Renaissance scientists. 

ND20-1-2023

Explanation

The Earth's Moon has considerably less mass than the Earth itself.

Not only is the Moon smaller than the Earth, but it is only about 60 percent as dense as Earth.

Thus, the gravitational attraction on the Moon is much less than it is here on Earth, and a person weighs less on the Moon.

ND20-1-2023

Explanation

The physical weight of our body is determined by the pull of gravity on it

ND20-1-2023

Explanation

When two surfaces slide over one another the tiny bumps push on each other.

Friction causes a force on a surface that is in the opposite direction to its motion.

Friction can be reduced by the application of lubricants

ND20-1-2023

Explanation

 non-magnetic materials are examples

• Rubber
• plastic
• stainless steel
• feather
• paper
• mica
• gold
• Silver
• leather***

  ND18-1-2023