Centrifugal Force


This is a great outdoor activity and was one of the class favorites of the year. Preparation: - one paper cup for each student (use a strong one, like those made for hot drinks - Tie a string to the cup by making two hole near the top across from each other and create a loop. Make it just long enough so that if a child holds the string with their arm relaxed, the cup will not touch the ground.

Can You Blow a Square Bubble?


We used this experiment as the class science fair project, and it worked out quite well. At the start of the class, I asked who had experience blowing bubbles. All but one of the first graders raised their hands. Then I told them that usually we blow bubbles using something like this (and showed them a typical bubble blower, a stick with a circle on the end), and then asked them about the shape of the bubble.

Red Cabbage as a pH Indicator


We learned last week that red cabbage is a general pH indicator. What is pH anyhow? The “potential” or “power” of Hydrogen: the pH scale measures the concentration of Hydrogen ions. If I had some phenolphthalein I would love to demonstrate turning water into wine. That page also has a great description of why pH indicators change colors when mixed with an acid or a base. “Different molecules absorb different colors of light, depending on their electronic structure.

Invisible Ink


There are many different ways to create inivisible ink. I didn’t want to use heat with a group of first graders, so we experimented at home with baking soda, vinegar, grape juice and red cabbage water (from wikipedia). It turns out after boiling red cabbage, the water turns a deep purple. This interacts with both vinegar (turning it bright pink) and baking soda (turning it blue-green). The color changes are dramatic when the liquids are mixed together – I thought that was even more fun than the invisible ink, which took most of the day to dry.

Flying Paperclips


Materials (for each child): 1 paperclip with a piece of thread tied to it 2 paper cups 2 popsicle sticks (we used large ones, might want 3 small ones) 1 washer tape The night before I practiced getting the paperclip to float in the air without touching the magnet to it. I did this with my six year old son to make sure that the kids would have enough dexterity for this.

Mixtures II: Vinegar and Baking Soda


In front of each child, I put a cup with the vinegar on top of a paper towel. Then I asked them to make observations about what was in the cup. Q: What does it look like? What does it sound like? What does it smell like? A: It looks and sounds like water. It smells yucky, like oil (sometimes it is mixed with oil and put on salads), like stinky socks (maybe your socks!

Mixtures I: Rocks and Salt


Before the class, I filled a cup of water for each student about 3⁄4 full and marked the water level. I put 5 rocks and a small cup of salt on a paper towel in front of each student. I asked them to tell me what they observed about the objects in front of them. My son shouts out “it’s salt!” I tell them to tell me what they observe, not what they think they know.



I thought this was going to be the most boring experiment ever. I didn’t have much time to prepare so I didn’t come up with anything more exciting than the basics. As it turned out, it was wonderful. Preparation (for class of 20): 20 droppers 20 cups of water 20 pieces (about 1” square) of: fabric (I used a small pices of flannel) aluminum foil wax paper

An Introduction to Time


My friend Max Carlson volunteered to be a guest scientist for our regular Tuesday first grade science class. He suggested that we teach about time. We started out planning to do time-lapse photography with his fairly high-end setup, but as we brainstormed how to get the kids involved, he suggested doing something more immediate: stop motion animation. I found a nice review of stop motion software tools where I found MonkeyJam.

Sink or Float?


First grade was a long time ago for me, so it took some getting used to that some of the basics are still new territory for these kids. I had a big science day planned. 1) an assortment of object to test whether they sink or float in water 2) 5 objects for which to form a hypothesis 3) conduct an experiment with those five objects and record the results