Download this free classroom poster to help your geography students understand how waterfalls are formed.
We’ve created this free waterfalls poster to help your students better understand how these spectacular features of river landscapes are formed.
How are waterfalls formed?
Waterfalls usually form in the upper stages of a river. As the river flows over bands of different rock, the water erodes soft rock more quickly than hard rock.
This undercuts the hard rock and leaves it overhanging. Because it is no longer supported by the soft rock, it eventually collapses.
When the hard rock overhang collapses, it falls into the plunge pool at the bottom of the waterfall. As it breaks up and the fragments swirl around, the rock causes more erosion.
The process is repeated over time and moves the waterfall further and further upstream.
As the waterfall retreats, a steep-sided gorge is formed.
See waterfalls in action
We offer several geography school trips that give students the exciting opportunity to see waterfalls in action. After learning how waterfalls are formed in the classroom (from differential erosion to undercutting, plunge pools and gorge formation), there's nothing quite like standing in front of one and seeing those river processes at work.
See waterfalls in action in Iceland
A school trip to Iceland is one of the best ways to help students experience waterfalls, erosion and fluvial landforms up close. On our geography trip to Iceland, groups can visit some of the country's most spectacular waterfalls, including Gullfoss on the Golden Circle and Seljalandsfoss and Skógafoss on the South Shore.
Skógafoss is one of Iceland's largest waterfalls, with a width of around 25m and a drop of 60m. Because visitors can walk right up to the wall of water, it's a brilliant opportunity for students to appreciate the sheer power of a plunge waterfall at close range.
Nearby Seljalandsfoss offers an even more unusual perspective, as visitors can walk behind the waterfall itself. This gives students the chance to see the falling water, spray and overhang from a completely different angle (which is a great way to bring waterfall formation to life).
Then there's spectacular Gullfoss. This waterfall is made up of two separate cascades, with the upper section dropping 11m and the lower section dropping 21m. That means students can compare different waterfall forms in one destination, helping them understand that waterfalls don't all look, behave or develop in the same way.
See waterfalls in action in the Americas
On a geography trip to Costa Rica, groups can visit La Fortuna waterfall in the Arenal region. Fed by the Fortuna River, this impressive waterfall drops around 70m through lush rainforest at the base of the dormant Chato volcano. The walk down to the waterfall includes around 530 steps, with places to pause on the way, giving students time to take in the tropical ecosystem around them. Once there, they can see how water, rock and vegetation interact in a dramatic rainforest environment.
A school trip to Toronto can include a visit to Niagara Falls, one of North America's most famous waterfall systems. Niagara Falls is actually made up of three waterfalls (Horseshoe Falls, American Falls and Bridal Veil Falls) on the Niagara River, which drains Lake Erie into Lake Ontario. Students can take a boat trip to see the Falls up close, feel the spray and hear the roar of the water. It's a powerful place to explore not only river processes and erosion, but also tourism, landscape management and hydroelectric power.
And on a West Coast USA geography trip, Yosemite National Park offers more extraordinary waterfall case studies. Bridalveil Falls drops 189m and flows all year round, while Yosemite Falls drops a total of around 740m, making it the highest waterfall in Yosemite National Park. Yosemite Falls is made up of three sections: Upper Yosemite Fall, the Middle Cascades and Lower Yosemite Fall. Together with Bridalveil Fall, these waterfalls help students connect waterfall formation with glaciation, hanging valleys and the wider story of how Yosemite Valley was carved.
Ready to start planning your trip?
Whether you choose Iceland, Costa Rica, Canada or the USA, we'll help you build a geography school trip that brings the topic of waterfalls and fluvial systems to life. Enquire today and tell us what your students are studying, what pace works for your group and what support you need, and we'll shape an itinerary that's safe, purposeful and unforgettable.