Explaining on Instagram: "Follow (us) @Explaining to learn something NEW every day 🧠‼️ In the 1960s, engineers developed a needle-free injector — a futuristic medical device that used high-pressure jets of liquid to deliver vaccines or medicine through the skin without a needle 💉➡️💨 It worked by shooting a fine stream of fluid faster than the speed of sound, penetrating the skin painlessly and reducing infection risks. Though the tech looked straight out of science fiction, it was actually us