Semester 1 Science Review for Grade 8

It digest and absorbs most of the nutrients in food, such as carbohydrates, proteins and fats.

It is a change of state in matter where gas has become liquid.

Which of the following colors does not belong in the spectrum of white light?

Is used to coat the striking surface on the side of a matchbox.

It is made up of two or more different types of elements that are chemically bonded.

It forms the building block of all elements and matter around us.

Are the substances produced by our body to speed up chemical reaction.

These are needed for growth and repair of damaged tissues in our body

Helps our blood to clot so that we do not bleed too much when we have a wound.

Churns the food and has hydrochloric acids and enzymes.

What is an element made up of?

The group of atoms chemically combined is known as

Too little of this causes anemia in which one lacks healthy red blood cells.

Which of the following is not an example of a carbohydrates?

Is an arrangement of all the elements known to man in accordance with their increasing atomic number and recurring chemical properties.

The main function of this component of blood is to protect our body from infection and diseases by engulping foreign materials such as viruses and bacteria, and kill them.

It is an example of beam of light where light rays meet at a point.

An object in water seems to be nearer to the observer as a result of

It carries tha blood away from the heart to the lungs and the rest of the body.

The arrangement of particles in this state are in random.

The movement of particles from a region of higher concentration to a region of lower concentration.

It is a process where the solid has become a gas and bypassed the liquid state completely.

It produces bile to help in breakdown of fats.

State where the liquid has become gas

This vitamin is usually found in citrus fruits; it helps us prevent from falling ill easily.

What type of image is formed in a plane mirror?

When light rays hit a dull or rough surface, light rays get reflected in all direction.

Which of the following is not a non-luminous object?

It is a type of ray that is going towards the mirror.

When light rays hit a smooth surface, light rays are reflected in the same direction. All reflected rays are parallel.

The total resultant effect of these forces exerted by all the gas particles is known as

The particle theory states that all matter is made up of small particles that are in constant random motion.

Gullet/ esophagus pushes the food down to the stomach through a process known as peristalsis.

A valve ensures that blood flows only in one direction in the heart.

Red blood cells are responsible for carrying oxygen around the body. They contain a substance called hemoglobin.

Some white blood cells produce substances called anti bodies to kill bacteria.

Atherosclerosis is caused by the build-up of substances, known as plaque, on the wall of the arteries.

A pinhole camera works based on the fact that light travels in a straight line.

A non-luminous object gives a color because it is reflecting off certain light rays.

Dmitri Ivanovich Mendeleev was a Russian chemist who was an important person in discovery of the modern periodic table.

Chemical symbols are used to represent elements; it usually takes the first letter or first two letters of the element's name.

During absorption, water and mineral salts will first enter the root hair cell. Next, the water and mineral salts will move into the neighboring root cells until they reach the transport tissue in the roots.

Incident ray is the type of ray that is going towards the mirror.

When we place a capillary tube in colored water, the colored water moves up the capillary tube. The phenomenon of water rising up a thin tube is known as the capillary action.

Light from the part of the straw that is in the water bends away from the normal as it enters the air and into our eyes

As light rays travels across two transparent mediums, such as air and water, it bends.

Xylem vessel transport water and dissolved mineral salts from the roots up the stems and to the leaves.

The root hair grows outwards into the spaces between the soil particles, where there is water with dissolved mineral salts.

An object in the water seems to be nearer to the observer as a result of refraction.

The capillary have thin walls that allow the diffusion of gases and nutrients to occur at a faster rate.

After the food has been breakdown into smaller pieces, it moves through a series of organ called alimentary canal.

When we do not consume sufficient nutrients from a particular food group or when our body is lacking a particular vitamin, we may develop nutritional deficiencies in our body.

Nutrition is the process of getting food and turning it to living matter.

Capillaries allow oxygen and dissolved nutrients to diffuse through them.

Arteries have valve.

Veins have the thickest walls among the blood vessels

Divergent beams are forms when light rays move outward from the source.

Light travels in a straight line

A magenta light filter will allow green light to pass through it.

The light of different colors travel at the same speed.

The phenomena of water rising up a thin tube is known as the capillary action

If we shine a green light on the apple, the apple will appear black to us. This is because the apple only reflects red light, but not green light.

Anemia is a condition in which one's blood does not clot normally.

Condensation happens when solid has become a gas and bypassed the liquid state completely.

Cells form the building block of all elements and materials around us.

The image formed in a pinhole camera is inverted.

The image formed in the plain mirror is smaller than the actual object.

The distance between the image and the mirror is the same as the distance between the actual object and the mirror.

The angle between the normal and incident ray is called the angle of incidence

Because of refraction, the object in the water seems to be closer to the water surface.

Light ray bend towards the normal as they travel from water into air.

Blood passes by the heart twice, once as deoxygenated blood and the other time as oxygenated blood.

The wall of a capillary is one-cell thick.

Xylem vessels are thin tubes that can be found in the roots, stem and leaf veins

Too little vitamin D can cause rickets which leads to weakening or softening of bones.

Digestion breaks down food particles physically to be absorbed by the body.

Give at least 3 characteristics of the image formed in a plane mirror.

State the two laws of reflection

Give atleast 2 functions of the blood

Explain how temperature affects gas pressure.

Describe how the structure of a leaf is adapted for photosynthesis.

Which organs are involved in the human digestive systems?

Give 5 examples of element in the periodic table and state their uses.

Describe and draw the 3 examples of beams

Explain how does light enable us to see.

Describe the difference between the regular and irregular reflection.

Give at least 3 signs of nutritional deficiency

Name at least 2 enzymes and describe its function

What are the colors of spectrum of white light?

What are the organs involve in human circulatory system?

What happens to the right and left ventricles when the heart muscles are relaxed?