Weather month continues, and this week we’re talking thermometers. Understanding temperature is pretty important if you want to talk about weather.
To begin, we made our own thermometers at home following these great tutorials at Steve Spangler Science and Lemon Lime Adventures. They’re pretty similar and both use materials that you probably have at home (or could easily get your hands on).
To make your own thermometer, you’ll need:
- a bottle, lid optional
- a clear straw
- poster putty
- cooking oil (optional)
- food coloring (optional)
- medicine dropper, pipette, or eye dropper (optional)
Both versions of this activity had the same main idea: fill the jar to all the top with water, put in your straw, seal the jar tightly.
Danya at Lemon Lime Adventures also adds extra water to her straw with the eye dropper until it’s about 2 inches above the opening of the bottle, and she adds a drop of cooking oil on top of the water in the straw to help prevent evaporation.
We tried out both and had some missteps and successes along the way.
If you’d like to use colored water, color it with food coloring or water color before adding it to your bottle. It’s just easier to mix up this way. This is a totally optional step but does make it a little easier to see the water in your straw.
Next fill your bottle all the way to the top. The eye dropper was helpful here in getting it to the very top. This is important because the thermometer works by showing a change in the water level. If the water has a long way to rise inside of the bottle, you’re not going to see it in the straw. This is also why Danya adds a little extra water to the straw.
Next, drop in your straw and seal the bottle. If you have a lid with an opening for the straw, use that and seal in the straw with poster putty so that it’s held in place with no leaks. If you don’t, you can use poster putty to seal the whole bottle.
This was so much easier on the soda bottle, by the way. For our peanut butter jar, we used a combination of plastic wrap and poster putty. With that method, it was pretty hard to get the jar to stay filled to the top and pretty easy to make a mess.
If you’d like to add a little water to your straw, add it in a little at a time with the eye dropper. Wait a while to make sure that the water stays in your straw. If it doesn’t, just add a little more.
If you’ve added water to your straw, you can also seal it by adding a little drop of cooking oil.
It took a few tries for me to get this one right, and in the end it wasn’t necessary to get the thermometer to work (but it’s my guess that it does work really well if you use the appropriate bottle).
When your thermometer is done, all you need now is to test it out.
We tried placing it by a sunny window, but there was no change.
Next I heated a bowl of water and placed the thermometer inside. It worked!
The water rose up the straw when it was placed in the hot water.
How this thermometer works:
When the water is heated, the water molecules expand. This makes the water to travel up the straw. This can only happen when your bottle is completely sealed and filled to the top because there’s nowhere for the water to go but up the straw.
We had plenty of leaks in our peanut butter jar thermometer, which is likely why we never got it to work.
Now that we had the basics of thermometers, we were ready to talk about temperature and practice drawing thermometers.
We used Kids Weather Report to talk about weather forecast and practice drawing thermometers. This site shows the weather in a way that even young children can understand.
This was also a fun way to teach Peas and Pie a little about the weather around the world. We typed in the location of all of our family members and saw how different the weather was in every location.
We talked about what the temperature means, and practiced showing the temperatures in the weather forecast by drawing thermometers. This helped us draw conclusions about where it was hotter and colder.
They were fascinated by the idea that it was not the same weather for family members in other parts of the country.
Next we looked up interesting places in the world, like Helsinki, Finland and Antananarivo, Madagascar.
Of course as we did this, there were all kinds of questions about the weather. I used Weather Wiz Kids a lot to answer them.
What’s the weather like where you are?
Learn about the water cycle and crystals in your own home with the Make a Crystal Experiment. It’s a little bit of chemistry, a little bit of weather, and a whole lot of cool science. Get the workbook with instructions, fun facts, and printable observation sheets now in the Free Trailblazer Club.