SCIENCE SA 2 PRIMARY 5

 

1.        The function of lenses : magnify or reduce the size of the images of objects.

2.       Where the lenses are used? Lenses are used in magnify glasses, microscopes, spectacles, cameras, telescopes, binoculars, and corrective glasses.

3.       How the heat is transferred? Explain your answer! Heat is transferred through conduction, convection, and radiation

-       Conduction is the transfer of heat from one part to another within an object or between objects by direct contact.

-       Convection is the transfer of heat from one region to another by the movement of fluids.

-       Radiation is the release of heat from the surface of most bodies that is transferred directly from one region to another.

4.       What is refraction? The bending of lght at the boundary of the two media.

5.       Why the refraction occurs? Refraction  occurs because the speed of light changes as it enters a different medium.

6.       What are the component of electric circuit? Explain your answer! Four component of electric circuit are

-       Energy source. The example of energy source is battery. The function of energy source is produce an electric current when the positive and negative terminals are connected.

-       Wires.  Wires are electrivcal conductors. The function of wires is connect one component of the circuit to another for electric current to flow.

-       Output device. Output device is an electrical appliance that uses electricity to work. The types of output devices such as buzzer, small elecltric fans, and light bulbs

-       Switch. The function of switch is for flow the electric current in circuit.

7.       Circuit diagrams and symbols

8.       The components of an electric circuit can be arranged in series or parallel

9.       How can we construct an electric circuit? Draw circuit diagram for represent it. Uses different symbols to represent the component.

10.   How can we increase or decrease the amount of electric current flowing through the circuit? By changing the number of batteries, number of bulbs, and arrangement of bulbs.

11.    How does sound travel? Sound travels away from thsouce in all direction.

12.   Sound requires a medium to travels. Sound can travel through solid, liquid or gaseous material. Sound travels fastest through solid material.

13.   What makes up soil? How is it formed? Soil is formed by the weathering the rocks that caused by :

-       Wind

-       Waves

-       Plants and animals

-       Frozen water

-       Water

-       Heat from the sun

-       Human activities

14.   What is soil erosion? Soil erosion is the removal of soil by wind and rain

15.   What are the causes of soil erosion?

-       Speed and volume of running water.

-       Amount of vegetation

-       Slope of land

-       Dryness and size of soil particles

16.   Effects of soil erosion :

-       Changes the shape of land

-       Condition of land. The soil may lose its fertility

-       Condition of water. Washed away may end up in ponds, rivers, and stream

17.   How to prevent soil erosion?

-       not cutting down trees unnecessarily.

-       Growing plants and crops along the slopes of hills and mountains.

-       Building retaining walls to hold back slopes of hills and mountains.

18.   What is the effect of the moon’s gravitational pull on the earth? Due to the tides can be low and high.

19.   What is the stars? Stars are big masses of glowing gas that always in the sky, but we cannot see them during the day because of the glare of the Sun.

20.   How are stars and constellations useful to use? They have been used to :

-       Locate objects in the sky

-       Locate directions

-       Entertain people

21.   How many planets in the solar system? What are they? There are 8 planets. Inner planets : Mercury, Venus, Earth, Mars. Outer planets : Jupiter, Saturn, Uranus, Neptune.

22.   How do planets in the solar system move? The planets move in similar patterns. All of them orbit the Sun in elliptical orbits (oval or almost circular)

23.   The time it takes a planet to complete one orbit called period of revolution.

24.   Period of revolution each planet :

Planet	Period of revolution
Mercury	88 days
Venus	225 days
Earth	365 days
Mars	687 days
Jupiter	12 years
Saturn	29 years
Uranus	84 years
Neptune	165 years

 

25.   The sun is so large, the gravititonal force it exerts is very strong. Without the pull of this gravitional force, planets orbiting it will move in a straight line endlessly into space. The Sun’s gravity pulls the planets towards the sun, which changes the straight path into a curve. This keeps the planets moving in orbits around the Sun.