Science Grade 8 Semester 1

What is the basic unit of life?

The cell

What is the difference between prokaryotic and eukaryotic cells?

Prokaryotes have no nucleus; eukaryotes have a nucleus.

Which cell structures control cell activities?

Nucleus

Which cell organelle provides energy?

Mitochondria

Name two features only found in plant cells.

Cell wall and chloroplasts

Why do cells divide?

For growth, repair, and reproduction

What is the function of the vacuole?

Stores water and nutrients

How do you calculate total magnification of a microscope?

Eyepiece lens × Objective lens

What are the parts of a microscope?

Eyepiece, objective lenses, stage, mirror/light, fine & coarse focus

What is DNA replication important for?

Ensures genetic material is passed on during cell division

Convert 1 mm to micrometres (µm).

1 mm = 1000 µm

Define an element.

A pure substance made of one type of atom

What is a compound?

A substance made of two or more elements chemically combined

What is a mixture?

Two or more substances not chemically combined

Give the formula for carbon dioxide.

CO₂

Is air an element, compound, or mixture?

Mixture

What are common features of metals?

Shiny, conductive, malleable

What does a particle diagram show?

Arrangement and movement of particles

What is the purpose of the periodic table?

To organise elements by atomic number and properties

What side are metals found on the periodic table?

Left side

What are non-metals like?

Dull, poor conductors, brittle

What are the 7 main types of energy?

Heat, light, sound, kinetic, potential, chemical, electrical

What is an energy transformation?

When energy changes from one form to another

What is an energy transfer?

When energy moves from one object to another

State the Law of Conservation of Energy.

Energy cannot be created or destroyed, only transformed

How do you calculate energy efficiency?

(Useful energy ÷ Total energy) × 100

What does an energy flow diagram show?

Energy inputs, useful output, and wasted energy

What are the three methods of heat transfer?

Conduction, convection, radiation

In which direction does heat flow?

From hot to cold

When does thermal energy transfer stop?

When both objects reach the same temperature

Which material keeps heat best in the cup investigation?

Insulating materials like foam or wool