fuel cells

Real Engineering explains why biofuels, especially corn ethanol, are a poor energy source, looking at energy inputs, efficiency and carbon cost.

Sabine Hossenfelder explains why hydrogen is a poor answer for decarbonization, covering how most hydrogen comes from fossil fuels, the efficiency losses of green hydrogen and reliance on rare metals in fuel cells.

Randall Munroe of xkcd answers what would happen if you swam in a spent nuclear fuel pool, and how much radiation you would receive at the surface versus at depth.

Real Engineering examines the efficiency of hydrogen as an energy carrier. It follows production, storage and fuel cell conversion losses and compares hydrogen cars with battery electric vehicles.

AVweb's Paul Bertorelli explains why general aviation has failed to replace leaded avgas, blaming industry inertia, bureaucratic delay and an exemption that removes the incentive. This is part one of two.

AVweb's Paul Bertorelli explains in part two of a series why general aviation has not replaced leaded avgas. He covers industry inertia, bureaucratic delays and the exemption that lets the industry keep using lead.

Physics Girl compares hydrogen fuel cell cars and battery electric cars after driving 1800 miles in a Toyota Mirai. The video was part of a series sponsored by Toyota.

A Kurzgesagt animation giving a big-picture tour of the human immune system, its organs, transport network, and the cells it produces every day. It accompanies their IMMUNE book.

Kurzgesagt compares how many people nuclear accidents have killed against other energy sources. It walks through the worst nuclear accidents and puts their death tolls in context per unit of energy.

A 20-minute S3 episode touring Terraform Industries, a startup making synthetic natural gas from air and solar power. It walks through the reactor, injection system, direct air capture and electrolyzer, plus the company's cost goals and next milestone.

Wendover Productions explains why modern airliners fly no faster than they did decades ago, covering the economics of speed and fuel efficiency, and why supersonic travel faded.

Engineering Explained examines new research suggesting corn ethanol in US gasoline may emit as much or more carbon than gasoline. It covers the Renewable Fuel Standard and why ethanol was assumed to be a green fuel.

All Cars with Jon explains how EPA fuel economy rules, especially the footprint-based CAFE formula, push automakers away from small trucks.

Cleo Abram's explainer on whether nuclear waste is really the intractable problem it is portrayed as, looking at how spent fuel can be recycled and used. It features a collaboration with Johnny Harris.

Everyday Astronaut explains the basic physics of rocket engines, the main engine cycles and fuel types, then compares SpaceX's methane-fueled full-flow staged combustion Raptor to other engines. It runs nearly 50 minutes with chapter markers.

Engineering Explained compares the lifecycle emissions of keeping an old car with those of buying a new, more efficient one. It weighs manufacturing emissions against emissions from driving, and covers gas versus electric cars.

Steve Mould shows that LEDs and solar panels are both diodes made from semiconductors, so a solar panel can emit light and an LED can generate electricity. He demonstrates a small solar panel lighting up.

Technology Connections explains why heat pumps matter right now, covering their efficiency, how they hold up in cold weather and the energy savings over burning fuel. It follows his earlier explainer on how they work.

Practical Engineering's explanation of the February 2021 Texas winter storm and the resulting power grid outage. It lays out the facts about ERCOT, the grid's isolation, and how generation across fuel types failed in the cold.

Veritasium tells the story of Thomas Midgley Jr., who introduced leaded gasoline and CFCs, and covers the science behind lead exposure and ozone damage. It also touches on isotope geochemistry used to uncover the history.

Not Just Bikes explains how SUVs and light trucks have grown in size and share of US sales, and why that is dangerous for pedestrians, cyclists and city life. He covers the regulatory loopholes, such as fuel economy rules and the chicken tax, that favored them.

A 36-minute animated deep dive from Branch Education into how DRAM works. It shows how memory connects to the CPU and how billions of bits are stored in nanoscale capacitor cells. It also covers why DRAM sits between SSDs and the processor.

A 2011 remix of over six hours of talks by Kirk Sorensen and other thorium advocates, explaining thorium as a nuclear fuel and the liquid-fluoride thorium reactor (LFTR). It argues LFTRs could produce energy without long-lived transuranic waste.

Real Engineering analyzes whether electric planes are feasible, focusing on battery energy density limits compared with jet fuel. It concludes electric flight works mainly for short ranges.

An animated Kurzgesagt explainer on bacteriophages, viruses that kill bacteria, covering how they infect and burst cells and their potential as therapy against antibiotic-resistant bacteria.

Astrophysicist David Kipping presents the halo drive, a proposed way to propel a starship to a good fraction of light speed by gaining energy from a black hole. The video is based on his peer-reviewed paper and explains why energy is the main obstacle to interstellar flight.

A Kurzgesagt animation about how the immune system constantly detects and kills cells that are turning cancerous. It explains what cancer cells are and why stopping them is so hard.

A Kurzgesagt animation of how the immune system responds to a bacterial infection, depicting immune cells as an army defending the body.

Veritasium explains X-chromosome inactivation, where different cells in a woman's body switch off different X chromosomes, giving a mosaic pattern. It uses animation from the WEHI institute and connects to calico cat coloring.

A short Harvard animation narrated by Professor Rob Lue introducing mitochondria as the cell's powerhouses and how cells turn food and oxygen into energy.

Scott Manley explains the nuclear salt water rocket, Robert Zubrin's concept of a rocket fueled by a rapid nuclear reaction in uranium salt dissolved in water. He covers its extraordinary performance and the dangers of managing it.

PBS Space Time surveys five realistic options for interstellar travel, from conventional rocket fuel to antimatter and nuclear pulse propulsion. The options rely only on known physics.