Carbon Footprint Calculator — How Heavy Is Your Family's Impact?
Tween estimates the family's weekly carbon footprint by examining transport, food, and energy use. Parent facilitates data gathering and discussion. This activity reveals systems thinking, numerical estimation skills, and environmental impact awareness through a real-world applied maths lens.
Opens a guided voice session in TogetherTime.
What you'll need
Paper and pencil for calculations. Optional: a recent electricity or gas bill, knowledge of typical weekly driving distances, and a rough sense of grocery shopping habits. A calculator is fine for the arithmetic — the thinking is what matters.
How it works
- 1~45s
Let's start with transport — it's usually the biggest chunk. Ask your child: 'How does our family get around in a typical week? List every trip you can think of — school runs, errands, activities, commutes.' Once they has a list, ask: 'How far is each trip, roughly? And how many times per week?' Then share this: an average car produces about 200 grams of CO2 per kilometre. Can your child estimate the family's weekly transport carbon? Let them work through the maths. Tell me how they approaches the estimation — does they think in systems or get stuck on individual numbers?
Watch for: systems_thinking_transport_audit
- 2~45s
Now let's tackle food and energy. For food, share this: beef produces about 27 kg of CO2 per kilogram, chicken about 6 kg, vegetables about 2 kg, and rice about 4 kg. Ask your child: 'Based on what our family eats in a typical week, can you estimate our food carbon?' Then for energy: an average household uses roughly 20 kg of CO2 per week from electricity and gas. Ask: 'What uses the most energy in our house? Heating? Hot water? Devices?' Tell me how your child handles juggling these multiple categories — can they see how all three areas (transport, food, energy) connect into one system?
Watch for: data_estimation_multi_category
- 3~40s
Time to put it all together. Ask your child to add up the weekly total across transport, food, and energy, then multiply by 52 for a rough yearly estimate. Share this: the average person in the UK produces about 5,000 kg of CO2 per year; the global average is about 4,000 kg; and scientists say we need to get to about 2,000 kg per person to avoid the worst climate impacts. Ask: 'Where does our family land? And if we wanted to cut our footprint by a quarter, what would be the smartest changes?' I'm listening for whether your child can prioritise — finding the high-impact changes rather than just listing easy ones. Tell me what they proposes!
Watch for: environmental_impact_prioritisation