By John Smith and Jane Doe Grade: 5 Mr. Gill’s Class

We began by forming groups of two and researching what materials were needed in order to construct our own thermometer. We came across these useful sites: thermometer.htm Do-it-yourself-science/Physics- experiments/thermometer-activity.aspx

As the temperature affects our daily lives by determining what clothes we wear and the activities we do outside, we thought it was important to understand the concept of temperature and how it is measured.

We gathered the materials that were needed: a clear bottle or container with a tight lid a clear drinking straw food coloring a permanent marker clay or adhesive water Note: In some variations of this experiment rubbing alcohol is mixed with the water because it is more sensitive to changes in temperature.

Materials:

First, we took the label off the bottle and filled it about 3/4 full. We added a few drops of food coloring to the water so it would be visible through the straw.

Next, we pushed the straw through the top of the bottle and firmly fitted the clay around the seal so that no air could escape.

We screwed on the top of the bottle, ensuring that the straw was about half way sticking out the top. We blew air in through the straw just enough so that the water level rose up the straw. This was made possible by the air-tight seal. We let the thermometer sit at room temperature for 10 minutes. Finally, we made a small mark with a permanent marker at the current water level, signifying room temperature.

Our thermometer was finished! It was time to test it out...

We decided to place the thermometer by the heater to see what would happen. As the temperature rose, the contents of the bottle expanded and the water level rose, causing the liquid to rise up the straw!

We then placed the thermometer outside, and of course we noticed the opposite effect. The water level dropped!

We used this weather observation sheet to track and record our findings. Each day for one week we measured the temperature outside and inside the school.

We wanted to do some research to explain our findings. We found that: “The thermometer uses the fact that most things expand as they warm up and contract when they cool down. If you raise the temperature of a gas, the particles that make up the gas absorb heat energy and begin to move faster. This causes the gas to expand. When the air inside the bottle expands, the pressure inside the bottle increases, pushing down on the liquid inside the bottle and pushing more liquid up the straw. When you cool the air again, it loses energy and decreases the pressure. The coloured water will then be pushed back down the straw by the pressure of the air outside.” 11

The End We hope that you will try this experiment at home!