teach.GLIN.net
GLIN Daily News About GLIN
AboutEnvironmentHistory/CultureGeographyPollutionCareers/BusinessTeachers' Corner
water photo
What's New?

Lessons in sailing, science
Superior Telegram (8/16)
A workshop offered by the Great Lakes Sea Grant Network has local educators on a six-day boat trip as part of the Duluth Tall Ships Festival.

NOAA to work with MTU scientists out on Lake Superior
WLUC-TV - Marquette, MI (8/16)
With the help of The National Oceanic Atmospheric Administration or NOAA, Michigan Technological University scientists continue to learn about their surroundings.

Sturgeon hatchery to offer tours in Onaway
WPBN-TV - Traverse City, MI (8/10)
The Michigan Department of Natural Resources is offering tours of the Black River sturgeon hatchery in Onaway. During the free tours, researchers will be available to talk about sturgeon biology, reproductive ecology and this year’s research.

Watch 4 months under Lake Michigan pass by in just 3 minutes
MLive (7/29)
Ever wonder what goes on underneath the surface of Lake Michigan? If so, you're not alone. Scientists wonder, too.

UMD researchers reveal data from wetland studies in the Northland
KQDS-TV - Duluth, MN (7/27)
From Green Bay Wisconsin to Duluth Minnesota, research is being conducted to figure out the current status of our lakes and rivers when it comes to invasive species, and other aquatic trespassers.

TEACH Calendar of Events
What's going on in your neighborhood this month? Meet other people and learn together at recreational and educational events! Our new dynamic calendar is updated daily with current educational events.
TEACH Questions & Answers

Do the Great Lakes have tides?
from Jean in Milton, Massachusetts and Thor in Davisburg, Michigan

The same forces are at work on lakes as on oceans -- the moon pulls on inland lakes, too. However, you won't find large tides on lakes as you do on oceans; lakes just don't have enough water in them for large tides to occur.

Dr. David Hollander -- a specialist in lake systems at Northwestern University -- was asked about tides on inland lakes. He said that the Great Lakes sometimes experience slight changes in water levels over short time scales, and in spring, there's a substantial influx of water due to melting of winter snows farther north. Yet, none these changes in water level can be called a true tide.

Click to see larger image. However, there is some disagreement on the subject. According to the Canadian Hydrologic/Hydrographic Service, the Great Lakes experience tides from 1 to 4 cm, the strongest being on Lakes Superior and Erie. These tides are often masked out by meteorologically induced phenomena, such as a seiche (pronounced "sayshe"). When wind pushes down on one part of a lake, the water surface rises in another part, producing waves (most noticeable on Lake Erie because the lake is so shallow).

Read TEACH's segment, Great Lakes water levels, for more information; if you'd like a more in depth explanation, download the Great Lakes Commission's Living with the Lakes brochure.

Thank you both for your question!


Answered on October 1, 2000

 

Return to Great Lakes Vault of Knowledge