Soup must stay at least 60°C for 2 hours, cost under $8, and weigh under 300 g. Which container should the team build?

Milk cartons must stay below 12°C for 3 hours in a 1 L carrier that costs $5 or less. Which design meets the criteria?

During a 45 minute walk, ice should remain mostly frozen in a reusable carrier under 150 g. Which design best fits that goal?

A glove warmer must reach at least 30°C in 5 minutes, last 20 minutes, and have mass under 60 g. Which design meets all criteria?

Medicine must stay below 5°C for 4 hours, with no leaking, and the cooler must cost under $6. Which design is best supported by the test?

A pizza sleeve must keep food above 50°C for 30 minutes, use recyclable materials, and cost under $3. Which test result meets the design constraints?

A cork sleeve around a mug keeps the outside cooler while the drink cools more slowly. Which heat-transfer path does the sleeve mainly reduce?

Under a heat lamp, a shiny cooler stays colder than a black cooler with the same foam thickness. Which heat-transfer path does the shiny layer address?

A bottle with two walls and a vacuum gap keeps cocoa warm much longer than a single metal bottle. What heat-transfer path is the gap designed to reduce?

Steam escaped from an uncovered soup jar, and the soup cooled quickly at the top. Which path would a tight lid mainly reduce?

A cooler insert divides the large air space above the food into smaller pockets. Which heat-transfer problem is the insert mainly trying to reduce?

In a cup test, the outside wall became hot while the lid stayed cool. The drink lost 12°C in 20 minutes. Which modification is best supported?

Two identical coolers were tested. The one in sunlight warmed 6°C more than the shaded one. Which modification follows from the evidence?

A cold box had samples near the loose lid 3°C warmer than samples near the bottom. What change should the team test next?

An iron-powder hand warmer reached 45°C in 4 minutes but cooled after 10 minutes. The goal is 35-40°C for 30 minutes. Which change is best?

An ice pack stayed at 0°C until all frozen gel melted, then warmed quickly. To keep samples cold longer, what should the team change?

A keeps soup above 60°C for 5 h, costs $18, weighs 700 g. B lasts 4 h, costs $7, weighs 300 g. Need 4 h and low cost. Which claim fits?

Foam shipper X holds vaccines below 8°C for 10 h but is single-use. Reusable shipper Y holds 8 h. The trip is 7 h and waste matters most. Which claim fits?

Hand warmer P lasts 4 h, costs $1, and is single-use. Warmer Q lasts 2.5 h, costs $12, and recharges. Hikers need 2 h and value reuse most. Which claim fits?

A seedling box must stay below 30°C and allow observation. A foil box stays at 24°C but blocks viewing. A clear box reaches 38°C. A clear shaded box stays at 27°C. Which claim fits?