1-How does the Law of Conservation of Energy explain why ice cubes melt in water? 2-What are the two differences between mass and weight?

3-Why does an object’s weight change on the moon but its mass stays the same?

4-Explain how two objects that have the same mass can have different densities.

5-How can you tell if a mixture is homogeneous (solution) or heterogeneous (not a solution)?
6-Identify each of the following examples below as either a homogeneous mixture (solution) or a heterogeneous mixture.
7-What are 3 methods you can use to separate a mixture? Give an example of each.
8-What is the difference between an atom and a molecule?
9-Is a compound a mixture or a pure substance?
10-How are elements arranged on the Periodic Table? by increasing
atomic number.

when atmosphere interacts with biosphere they focuses on on the sources and sinks of green house gases (ghgs) air pollutants, particular matters, water and energy between the earth's surface and the atmosphere. the biosphere affects the climate. the atmosphere and biosphere are in constant interaction with each other, and all living things rely on gases in the atmosphere for life. organisms such as animals take in oxygen gas form the atmosphere to use in every cell of their body for smooth functioning of daily routine exercises.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.

b) nuclear ive learned that in a pedtrodic table