Science Experiments

Archive for January, 2010

Question: How do you measure different amounts of CO2 (gas) to put in a flask?

This is for a science experiment.
One of the steps is to use four flasks and put different amounts of CO2 (from dry ice) in each flask and seal the flask.
Flask A will have 62.5mL of CO2.
Flask B will have 125mL of CO2.
Flask C will have 187.5mL of CO2.
Flask D will have 250mL of CO2.
Any suggestions as to how to measure the amount of gas and how to put the gas in a flask without any of it escaping?

Answer: CO2 is denser than O2, so it will settle on the bottom of the flask. It will only spill out of the flask if you overfill it–just like a liquid does. I’m not sure how you would measure it, though. I’ve never tried to pipet it. That might work. I’m assuming your flasks are not graduated to 0.5mL. If they are you can just fill the flask to the appropriate gradation.

If your teacher lets you, it’s kind of cool to put a few pieces of dry ice (maybe six) into a lab sink and turn on the water. You’ll see the gas fill up the sink, then spill over it like it was liquid. It’s very cool.

Scientific Tuesdays – Awesome Dry Ice Experiments

Below is a video of instructions on how to make a compass with a needle. With just a needle, you can make your own compass easily at home. Follow the instructions on how to make a compass in the vidoe below. But, be sure to be supervised by an adult when doing the compass making experiment.

How do you make a compass?

How to Make a Compass instructions for Science Experiments

In this video, we show you how to make a compass with a needle and a piece of foam but you can use anything else to hold the needle in place. Sometimes, people refer to this making a compass science experiment or activity as how to make a compass out of soap when they use a piece of soap to hold the magnetized needle in place.

Video of instructions on how to make a compass

Question: Ideas for an experiment….?

Hello,
I am a student in high school and currently doing Physics and Chemistry. We are supposed to do an experiment in groups of four involving students from Physics, Chemistry, Biology and Environmental Systems. There should be some kind of a role of all these subjects. Anyone with any ideas, for a good experiment as it is going to be assessed??
I need an experiment which can be done in a day or in a maximum of two days. Any help will be appreciated thanx.

Answer: You could try making a Winogradski Column. It’s a common microbiological experiment where you pack layers of pond mud and water with wetted cellulose (ripped paper) layers in a glass measuring cyclinder (500mL-2L is really good) and culture the microorganisms in this column over a period of time.

The biological side… you can look at the microorganisms you have under the microscope (paramecium are common in pond water and motile in a drop of water on microscope slides).

The chemistry side… microorganisms deep in the column grow anaerobically (without air) and you will get hydrogen sulfide producers that can be detected by the smell of rotten eggs and the visual presence of black hydrogen sulfide waste deposits deep in your cultured column.

The environmental side… observing the flora in an environmental niche (making columns from flowing verses stagnant ponds may grow different types of columns, or comparing garden mud and tap water to pond mud and water would give visible differences).

The physics side… measuring the electrochemical potential between the top and bottom of your cultured column (see http://www.biofilmsonline.com/cgi-bin/biofilmsonline/ed_contruction_winogradsky.html) before and after culturing the column, and discussing the results in relation to your cultured microorganisms.

It’s a very easy experiment to set up, and you can measure a lot of things over a period of time (eg. measurements every week for five weeks). You can also set up a column exposed to day-light verses one covered with foil to see the difference on what you grow.

You will find protocols for the column on Google… read a couple and follow, making sure you seal the top of your columns whilst culturing them (plastic wrap or parafilm is good).

Best of luck!

High school chemistry Mentos & Coke experiment