Learn.

You buy a sandwich. That small moment involves sunlight, a living body, something you want, and people whose work brings food to you. Follow the connections and the bigger picture appears.

One ordinary event connects the physical world, your inner life and the society around you.

Your lunch begins with sunlight.

Plants use energy from sunlight to make food molecules. They also need water and materials from their surroundings. Growing, moving and preparing your lunch all depend on physical supplies.

Energy flows through the system. Matter supplies the materials.

Inside the bread are molecules.

Bread contains substances such as starch, water and proteins. These contain atoms joined in particular arrangements. Chemistry explains how substances change as food grows, cooks and is digested.

The zoom means “made of”. The shapes represent molecules; their real structures are much smaller.

Your cells put those materials to work.

Digestion breaks food into smaller parts your body can absorb. Cells use these materials to build, repair and support the chemical reactions that keep you alive. Those reactions also transfer energy for cell work.

Food is broken down, absorbed and used. The cell picture groups many different chemical steps.

Your body and brain keep talking.

Hunger and fullness involve messages between your body and brain. Nerves carry signals. Hormones carry chemical messages. Eating changes these messages and helps influence what happens next.

Eating changes the body; the changed body influences the next response. This is feedback.

What you want shapes what you choose.

Desire is a pull towards something you expect to value. You may want a familiar taste, convenience or time with a friend. Body signals, memory, other people and available choices can all influence what you pick.

These influences interact. Their importance varies between people and situations.

Your spending becomes someone’s income.

You pay the café. Its income helps pay for ingredients, staff, energy and other costs. Those payments become income elsewhere. Many purchases connect what people want with what other people make and provide.

Food travels towards the customer. Payment travels towards the business and its suppliers.

The world also shapes your choices.

Food reaches you through roads, businesses, shared rules and natural resources. These affect what is available and affordable. Food production changes land and water use, linking today’s meals to future supplies.

Rules and resources influence production. Production changes the conditions that later choices depend on.

Each change can travel around the system.

A complex system has many connected parts that influence one another over time. Food changes your body. Experience shapes later choices. Purchases can influence what shops offer. Production changes the surroundings that future food depends on.

Feedback means a result returns and influences what happens next. Timing, circumstances and limits shape the outcome.

Physics

Matter, energy and the physical world

A cup has weight. Water heats up. Light reaches your eyes. Physics helps explain these physical changes.

What is everyday stuff made of?

What does energy do?

What is the physical world made from?

What are voltage and current?

Atoms interact and form substances

Chemistry

How atoms join and substances change

Air, water and food contain atoms. Chemistry explores how those atoms join, rearrange and make substances with different behaviours.

What is chemistry?

Atoms: small ingredients with different behaviours

Chemical bonds: joining and rearranging atoms

Water: the moving environment of cells

Living things use this chemistry

Biochemistry

The chemistry happening inside living things

Inside a cell, molecules help build parts, use food and pass messages. Biochemistry follows these chemical jobs.

Biochemistry: the chemistry of being alive

Proteins: folded molecules that do work

ATP: coupling reactions to cellular work

Metabolism: connected chemical pathways

Molecules keep cells working

Biology

Cells, living things and their surroundings

A bacterium, a tree and a person are living things. Biology explores how life works, from a single cell to whole organisms and their surroundings.

What is biology?

How do tiny parts make a living body?

Cells: organised chemistry inside a boundary

How do brain cells pass messages?

Your brain is part of your living body

Brain & psychology

Sensing, feeling, wanting and choosing

Your brain works with your body as you notice, remember and act. Psychology also explores how learning, relationships and circumstances shape behaviour.

What does your brain do?

How do we make sense of the world?

Reinforcement

Social norms

People make choices and act together