RespirationRespiration is a series of chemical reactions, in cells, that breaks down glucose to provide energy

and form new molecules. Most living things use aerobic respiration but switch to anaerobic respiration, which provides less energy, when oxygen is unavailable.

What happens to the pulse rate whilst someone is

running?The body needs to release more energy:

so oxygen and glucose need to reach

muscle cells quickly;

so blood is pumped around the body faster;

so the pulse is faster.

Diffusion is the net movement of

molecules or atoms from a region of high

concentration to a region of low

concentration as a result of random

motion of the molecules or atoms.

Glucose used as an energy source, to build new tissue, or store it for later use

Factors affecting rate of photosynthesis

Leaf adaptationsWhat do plants use the products of photosynthesis for?

Photosynthesis*Broad and flat – capture lots of sunlight

* Cells at top of leaf contain lots of chloroplasts – site of photosynthesis.

* Small holes called stomata in the underside of a leaf allow gases in and

out.

Key wordsChemical bond a force holding two atoms togetherEndothermic a reaction that takes in energy, the temperature drops.Exothermic a reaction that releases energy so the temperature increasesBond energy the energy needed to pull two atoms apart (break the bond).Hazard a situation that prevents a threat to people.Risk how likely something is to be harmfulControl measure an action taken to remove the hazard or reduce exposure to it.Benefit something good or helpfulCatalyst a substance that when added speeds up a reaction, but isn’t used up, so can be reused.

Assessing riskWhat risks/hazards do chemical

experiments pose?

How can we ensure that we are safe when we do

chemical experiments?

Key wordsChemical reaction a change in which a new substance is made – or bonds are broken in the reacting particles and new bond form in the product particles. The particles themselves have changed.Physical change one that changes the physical properties but no new substance is formed – or the particles are rearranged but the particles themselves have not changed.Fuel stores energy in a chemical store which can be released as heatReactants substances that react together, shown before the arrow in an equation.Products substances that are made, shown after the arrow.Conserved when the quantity of something doesn’t changeCombustion a substance reacting with oxygen, releasing heat and light.Thermal decomposition a single substance is broken down by heating

Mass changes in Chemical reactionsAlthough the total mass will stay the sameThermal decomposition reactions appear

to lose mass as gases are released.Combustion may lose mass as gases are

released.

Thermal decomposition

Can be represented by diagrams:

Copper copper oxide + carbonCarbonate dioxide

A magnetic material can be magnetized or will be attracted to a magnet. Some examples of magnetic metals are:

• Iron

• cobalt

• nickel

Attraction and repulsion:opposite poles attract, and like poles repel.

The magnetic field is strongest at the poles, where the field lines are most concentrated.

we cannot see magnetic fields, we can detect them using iron filings.

The iron spinning in the core causes a magnetic field to surround the Earth. This helps protect us from solar winds from the sun!

When an electric current flows in a wire, it creates a magnetic field around the wire. This effect can be used to make an electromagnet.

We can make an electromagnet stronger by doing these things:• wrapping the coil around an iron core• adding more turns to the coil• increasing the current flowing through the

coil.

Electromagnets have some advantages over permanent magnets. For example:• they can be turned on and off• the strength of the magnetic field can be

varied

The magnetic field around an electromagnet is just the same as the one around a bar magnet. It can, however, be reversed by reversing the current (turning the battery around).