Fun fact: Did you know you can float more easily in the Dead Sea than in any swimming pool? That’s because saltwater is denser, and we explored this and much more at this year’s Isle of Barra & Vatersay Science Festival!
On the 3rd and 4th of July, the beautiful islands of Barra and Vatersay hosted their Science Festival 2025 edition, a celebration of nature, science and creativity for all ages. This year’s theme, “The Land, the Sea, the Sky,” inspired a wide range of activities: from inspiring talks to hands-on experiments for the whole family.
The Decentralised Water Technologies (DWT) group brought along three interactive exhibits across both days, each designed to spark curiosity and start conversations around science and our environment. As for the 2023 edition, we included posters in Gaelic again to ensure inclusivity, as Gàidhlig is the first language of the Outer Hebrides.
From Land to Sea to Sky: Discover the Life in the Scottish Islands
Our biodiversity board invited visitors to help map the wildlife of the Outer Hebrides. Armed with stickers, people marked where they’d spotted local species: from sheep and red clover to seagulls and the (less beloved) midges. We were especially thrilled to see participants of all ages contribute their own colourful drawings, some of which were worthy of an art gallery! Whether professional or playful, each illustration added charm and helped us build a vibrant community mural of local life.
Hold Back the Waves!
Day one featured our flooding challenge, with interactive flooding models kindly provided by the Glasgow Science Centre. Participants first built their own LEGO homes, which they then tested against simulated wave conditions using various materials, including wood, grass, and rocks, to protect them. As the waves rolled in, the science flowed! Families learned how climate change and rising sea levels are especially serious for island communities like Barra & Vatersay. We explored how vario
us flood defences, both natural and artificial, can mitigate damage. It turns out that rocks helped break the waves’ energy, but grassy, absorbent soil offered the best protection, especially in a place as naturally soggy as Scotland!
Participants also shared their own experiences with flood barriers, from sandbags to temporary walls they’d seen both on the islands and the mainland.
Swim or Sink: The Science of Density
On day two, we explored why it’s easier to float in the sea than in a swimming pool, and it’s all about salt and density! We offered three different water samples: tap water, local Barra seawater, and a super salty simulation of the Dead Sea. Visitors dropped everyday objects into each and observed whether they sank or floated. Then came the challenge: could they guess which water sample was which based only on how the objects behaved?
Spoiler alert: things really floated in the Dead Sea simulated water!
With a 35% salt concentration, this salty solution was incredibly dense, much denser than tap or regular seawater. The higher the density of the liquid, the more it pushes up on objects placed in it. That’s why even objects that normally sink in tap water bobbed right to the surface. It’s nearly impossible to sink in the real Dead Sea, and our experiment gave a pretty good demonstration of why!
The Rise and Fall of the Water Industry
Professor Bill Sloan delivered a powerful and thought-provoking talk on the history of water systems in the UK. His presentation took us from the early days of water treatment, driven by public health, to the modern challenges of sustainability, equity and energy use.
Prof. Sloan highlighted the need for innovation but also addressed the systemic corruption and commercial pressures that too often slow progress. His message was clear: we need to put people and the planet before profit, and push for an industry that’s transparent, sustainable, and truly serves the public good.
From building LEGO houses to creating beautiful drawings and dropping balls into buckets of saltwater, the Isle of Barra & Vatersay Science Festival 2025 was a joyful mix of fun, learning, and community spirit. We were delighted to connect with local residents, visiting families, and curious minds of all ages.
Thank you to all who stopped by to explore the land, sea and sky with us, and to everyone who shared a story, a drawing, or a smile. See you at the next adventure!
