Exam🥲

Question 1

Identify some common mixtures

Answer 1

Sand and water.
Salt and water.
Sugar and salt.

Question 2

Identify the solute and solvent in common mixtures.

Answer 2

Solute: substance that is dissolved in a solution is called a solute. Solvent: you dissolve a solute in here to create a solution.

Question 3

whats filtering?

Answer 3

the process in which solid particles in a liquid or gaseous fluid are removed by the use of a filter

Question 4

whats sieving

Answer 4

The process of separating fine particles from the larger particles by using a sieve

Question 5

whats decanting

Answer 5

the process of pouring away a liquid while leaving a solid

Question 6

distillation

Answer 6

heating a liquid to the boiling point

Question 7

evaporation

Answer 7

water changes into a gas or water vapor

Question 8

crystallization

Answer 8

when a chemical it converted from a liquid into a solid crystalline state.

Question 9

Chromatography

Answer 9

separating a mixture of chemical substances into its individual components

Question 10

How is salt separated from seawater from desalination plants

Answer 10

reverse osmosis technology to separate water molecules from seawater.

Question 11

Identify solar and lunar eclipse

Answer 11

Solar is when the moon is in the middle and lunar is when earth is in the middle.

Question 12

What is mass, weight, and unit of force?

Answer 12

Mass is the amount of matter in an object and weight is a force due to gravity pull. Weight is measured in Newton’s coz it’s a force. unit of force is n.

Question 13

What’s renewable and non renewable?

Answer 13

Renewable is something that can be used repeatedly and does not run out because it’s naturally replaced. Non renewable is when something will run out or will not be replenished for thousands or even millions of years.

Question 14

What’s speed multiplying machines and force multiplying machines?

Answer 14

Speed multipliers are devices that increase the speed of, or distance travelled by, an object and force multipliers are devices that increase the force of and object.

Question 15

How can a mechanical advantage be obtained from simple machines?

Answer 15

Multiply the idea mechanical advantage of the simple machine

Question 16

Distinguish between simple and compound machines

Answer 16

Simple machines are levers, pulleys, wheel and axles, wedge, screws and inclined planes. Compound machines are two of these together

Question 17

Identify how simple machines work together in compound machines

Answer 17

Simple machines are attached together to make compound machines, for example a crane.. if there was no pulley, it would just be a lever moving up and down. That doesn’t make life easy.

Question 18

Explain the seasons in terms of the tilt of the earths axis and the orbit of the earth around the sun.

Answer 18

when the North Pole tilts toward the Sun, it’s summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it’s winter in the Northern Hemisphere.

Question 19

Describe the developments of models of the universe and solar system put forward by astronomers.

Answer 19

Firstly, Plato discovered that the planets followed perfectly circular motions around the sun. Then Heraclides decided to make a model of it by placing the planets in the correct order from the earth. They called it the geocentric solar system model.

Question 20

Explain why the amount of daylight varies from season to season and distance from the equator.

Answer 20

because the hemisphere is tilted away from the sun, it wouldn’t get as much light as the hemisphere that’s directly getting the sunlight. This brings warmer weathers meaning different seasons.

Question 21

How to reduce friction.

Answer 21

Machines and engines use grease and oil to reduce friction so they can last longer.