Friday, 3 June 2016

How Fish Breathe - A Science Experiment

This week's Unit Study Roundup is on the theme of aquariums. We attend a monthly Science Club and one of the experiments or demonstrations that we did is showing how gills work, or how fish breathe.

Humans use their lungs for breathing and the lungs are part of the respiratory system. Fish have gills that extract or take oxygen out of the water.

H2O is another way of writing water. Hydrogen times 2 and Oxygen is what water is made up of. Here is a photo of water molecules. My daughters both thought it would be funny to tell me that they spilled water on the sofa. This is what I found:



The red represents hydrogen and the white represents oxygen - H2O. The fish extracts the oxygen gas from the water.

A fish opens its mouth and gulps water and pumps it over the gills. The gill cover is open when the mouth is closed. When the mouth closes, the gill cover opens and this forces the water into the gill chamber. Inside the gill chamber, they have fabric like threads that are called filaments that are connected by a gill arch that is in two rows.

There are also thin plate-like structures called lamellae. Blood flows through the lamellae and filters the oxygen from the water and releases carbon dioxide into the water.

After the fish gets its oxygen from the water, it passes out through the gill openings and the breathing process begins again.

Here are some pictures of fish gills, the real fish in the picture is a carp. The other pictures show the parts labelled:


To demonstrate this, you need:

- A clear glass (or a plastic cup),
- coffee grounds,
- a coffee filter or a piece of paper towel,
- an elastic band,
- and some water.


First mix the water and coffee grounds. Then, put the filter over the cup and secure it with the elastic band.


Pour the water and coffee ground mixture over the filter and watch the water go through the filter down into the glass. The coffee grounds will stay in the filter. I wasn't very careful and managed to get the mixture on my table.


The filter represents the gills. The coffee grounds represent the oxygen that the fish gets from the water. The water that passed through the filter into the cup represents the water that the fish pushes out through the gill chamber with the carbon dioxide in it.

Here is the final product:


This picture is of my daughter presenting the experiment to the other families in our Science Club:

Here is a video that you can watch. We used this in our presentation at Science Club.

Please be sure to read the other posts from the Unit Study Roundup. The theme for this week is Aquariums.







Aquarium Animals Letter Find Worksheets from 3 Boys and a Dog

Under the Sea Fun Octopus Vegetable Platter from Crafty Mama in ME

Aquarium Arithmetic Seek and Find from Look! We're Learning!

Fish Books for Kids from The Jenny Evolution

How Fish Breathe - A Science Experiment from Tales of Education at Home

Fun Things to See at the Newport Aquarium from Something 2 Offer

Aquarium Scavenger Hunt Printable for Kids from CraftCreateCalm

Aquarium in a Bottle: Ocean Sensory Idea from A Little Pinch of Perfect

Aquarium I Spy from Schooling a Monkey

Finding Fish Learning Placemat from Books and Giggles

Snorkeling with Kids in Thailand: A Live Aquarium from FrogMom