Series Circuits

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Series Circuits

If a circuit is set up as a series circuit it will be set up as one continuous loop.

Series circuits

In a series circuit, components are added in a loop.
There are no branches in a series circuit.
For the components to work, the circuit must be complete.

Bulbs in a series circuit

The more bulbs you add in a series circuit the dimmer they will be.
The more cells you add the brighter the bulbs will be.
If there are two or more bulbs in a series circuit and one bulb breaks, the circuit will be broken and current will not flow.

Current in series circuits

Current in a series circuit remains the same everywhere in the circuit.

Potential difference in series

Potential difference is shared with all the components in the series circuit.
The total potential difference of the components will equal that of the cell or battery.

Parallel Circuits

If a circuit is set up as a parallel circuit it will be set up with branches.

Parallel circuits

Parallel circuits have branches.
The branches form different loops in which current can flow.

Bulbs in parallel circuits

If one bulb breaks in a parallel circuit the other bulbs will remain on.
If you add more bulbs to different branches the other bulbs will not get dimmer.

Current in parallel circuits

The current is split among the circuit's branches.
If there were two branches each with a bulb they would each share half the current that was originally in the circuit.
The current will be the same at the start and end of the circuit.

Potential difference in parallel circuits

The potential difference across the different components is equal to that of the cell or battery.
If there were two branches each with a bulb they would each have the same potential difference as the cell or battery.

Resistance

If you resist something, you try to fight against it and stop it happening. Resistance happens in electrical circuits when a component resists the flow of current.

Resistance

Most conductors will restrict the flow of current in a circuit.
If you want less current to flow, you can increase the resistance.
There is more resistance in a wire if:
- The wire is longer.
- The wire is thinner.
Insulators will have a very high resistance so a current will not flow through them.

Tasers

Some UK Police Officers carry a taser – this is used as a non-lethal method of restraining a violent person.
The taser can deliver a potential difference of 50,000 V.
However this is not deadly as the high resistance ensures it only delivers a very small current (around 0.002 A), just enough to make the suspects muscles relax.

Calculation

Resistance is measured in ohms.
The symbol for ohms is the Greek omega symbol (Ω).
Resistance can be calculated using the equation:
- Resistance (Ω) = potential difference (V) ÷ current (A)

Ohm's law

A resistor is said to follow Ohm's law if:
The current that flows through it is directly proportional to the potential difference.
This means if you double the potential difference the current will also double.
A directly proportional relationship when you draw it on a graph is a straight line through the origin.

1Biology

1.1Cells, Tissues & Organs

1.2Reproduction & Variation

1.2.1Reproduction in Humans

1.2.2Male Reproductive System

1.2.3Female Reproductive System

1.2.4Gestation

1.2.5Pregnancy

1.2.6Puberty

1.2.7The Menstrual Cycle

1.2.8Reproduction in Plants

1.2.9Pollination

1.2.10Dispersal Method

1.2.11Variation

1.2.12Causes of Variation

1.2.13Inheritance

1.2.14Adaptations and Evolution

1.2.15Species & Selective Breeding

1.2.16Genetic Conditions

1.2.17End of Topic Test - Reproduction & Variation

1.3Ecological Relationships & Classification

1.4Digestion & Nutrition

1.4.1Balanced Diets

1.4.2Vitamins & Minerals

1.4.3Protein

1.4.4Lipids, Oils and Fats

1.4.5Carbohydrates

1.4.6Starch

1.4.7Energy Needs

1.4.8Dietary Fibre

1.4.9Diseases Caused by Nutritional Deficiencies

1.4.10Digestion

1.4.11Plant Nutrition

1.4.12Enzymes in Digestion

1.4.13Required Practical - Enzymes in Digestion

1.5Plants & Photosynthesis

1.5.1Roots

1.5.2Photosynthesis

1.5.3Leaves

1.5.4Rate of Photosynthesis

1.5.5Testing the Rate of Photosynthesis

1.5.6Water Transport in Plants

1.5.7Translocation

1.5.8The Carbon Cycle

1.5.9Human Activities & Carbon Dioxide

1.6Biological Systems & Processes

2Chemistry

2.1Particles

2.1.1Particles

2.1.2States of Matter

2.1.3Changes of State

2.1.4Properties of States of Matter

2.1.5Diffusion

2.1.6Changing State

2.1.7Pressure

2.1.8Temperature Increase in a Gas

2.1.9Conservation of Mass

2.1.10Purity of Substances

2.1.11Pure Substances

2.1.12Evaporation

2.1.13Mixtures

2.1.14Separating Mixtures

2.1.15Distillation

2.1.16Chromatography

2.1.17Solubility

2.1.18Investigating Solubility

2.2Chemical Reactions

2.2.1Chemical Reactions

2.2.2Common Reactions

2.2.3Acids & Alkalis

2.2.4Reactions of Acids

2.2.5Testing for Hydrogen

2.2.6The pH Scale

2.2.7Titration

2.2.8End of Topic Test - Chemical Reactions

2.3Atoms, Elements, Compounds

2.3.1Atoms

2.3.2Elements

2.3.3Compounds & Mixtures

2.3.4Electron Configuration

2.3.5Chemical Symbols

2.3.6Chemical Formulae

2.3.7Conservation of Mass

2.3.8Vacuums

2.3.9Molecules

2.3.10End of Topic Test - Particles & Atoms

2.4The Periodic Table

2.4.1Physical Properties

2.4.2Chemical Properties

2.4.3The Periodic Table

2.4.4Metals

2.4.5Non-Metals

2.4.6Alkali Metals

2.4.7Halogens

2.4.8Oxides

2.4.9End of Topic Test - The Periodic Table

2.5Materials & the Earth

2.6Reactivity

2.6.1Ions

2.6.2Ionic Bonding

2.6.3State Symbols

2.6.4Balancing Chemical Equations

2.6.5Relative Formula Mass

2.6.6Calculating the Relative Formula Mass

2.6.7The Reactivity Series

2.6.8Carbon & The Reactivity Series

2.6.9Displacement Reactions

2.6.10Displacement Reactions - Halogens

2.6.11Alloys

2.6.12Metal Alloys

2.7Energetics

2.7.1Measuring Gas Production

2.7.2Observing a Colour Change

2.7.3Analysing Reaction Rates

2.7.4Factors Affecting the Rate of Reaction

2.7.5Catalysts

2.7.6Testing for Oxygen

2.7.7Energy Changes During Reactions

2.8Properties of Materials

2.8.1Testing for Gases

2.8.2Alloys

2.8.3Density

2.8.4Density of Solids, Liquids & Gases HyperLearning

3Physics

3.1Energy

3.2Forces & Motion

3.3Waves

3.4Electricity & Magnetism

3.4.1Circuit Symbols

3.4.2Resistors & Diodes

3.4.3Electric Current

3.4.4Measuring Current

3.4.5Potential Difference

3.4.6Series Circuits

3.4.7Parallel Circuits

3.4.8Resistance

3.4.9Charges

3.4.10Static Electricity

3.4.11Magnets

3.4.12Magnetic Fields

3.4.13The Earth's Field

3.4.14Electromagnetism

3.4.15Uses of Electromagnets

3.4.16Strength of Magnetic Fields

3.4.17Circuit Symbols HyperLearning

3.5Matter

3.6Space Physics

3.6.1The Sun

3.6.2The Planets

3.6.3Other Astronomical Bodies

3.6.4The Milky Way

3.6.5Beyond The Milky Way

3.6.6The Seasons

3.6.7Days, Months & Years

3.6.8The Moon

3.6.9Light Years

3.6.10End of Topic Test - Space

4Thinking Scientifically

4.1Models & Representations

4.1.1Strengths & Limitations of Models

4.1.2Symbols & Formulae to Represent Scientific Ideas

4.1.3Analogies in Science

4.1.4Changing Models – Atomic Theory

4.1.5Working Safely in the Lab

4.1.6Variables

4.1.7Writing a Hypothesis & Prediction

4.1.8Planning an Experiment

4.1.9Maths Skills for Science

4.1.10Drawing Scientific Apparatus

4.1.11Observation & Measurement Skills

4.1.12Types of Data

4.1.13Graphs & Charts

4.1.14Bias in Science

4.1.15Conclude & Evaluate

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