Hypothesis Practice

This week my students practiced writing a hypothesis. To practice writing a hypothesis have  your students complete this engaging activity that gives the them a chance to practice their hypothesis writing.  This activity requires a 2 liter bottle, water and tape (masking or painting). Prepare the bottle by drilling three holes vertically in a straight line  about and inch apart. The holes should be  slightly smaller than a pencil eraser. I have used scissors and twisted them until the a hole was made but a drill is much easier if you have it.  Once the holes are drilled place some tape over the holes and fill it with water.

 

 

 

 

 

 

 

 

Your bottle is now ready for the class.  Prior to getting started  with the hypothesis practice have the students create a chart that looks like the one below making sure they save room to write inside the chart. If students are using an interactive notebook have them place this chart on the right side.

 

 

 

 

 

 

 

On the left side of the their interactive notebook students will record their initial observations and their sketch. When students are done  with the entire activity it will look like this.

 

 

 

 

 

 

 

To begin this activity, walk around the room to each student so they can closely observe the bottle and record their observations. This is where  you can emphasize details in their observation records. After walking around ask the class for a volunteer who isn’t afraid of water. Bring the student to the front of the class and sit them in a desk and give them a paper towel to put on top of their head (optional).  The purpose for involving a student is for dramatic effect and student engagement and it works very well! In addition.I also ask students after we are done if it influenced what they thought might happen and then use that as an opportunity to discuss bias. They shouldn’t actually get more than a drop or two of water on them if all goes well.  While holding the bottle over the volunteers head ask the class to record their hypothesis about what will happen when the tape is pulled past the first hole. Ask students to write the hypothesis. Have the students share their hypothesis with the class. Next, pull the tape past the first hole while holding it over your volunteers head. If everything is done correctly, no water will come out of the first hole. Students record their observations and record why they think it happened the way it did or any questions they may have.  Move on and repeat this for the next two holes. Have the students make a hypothesis before each  a new hole is exposed. Water will come out of the next two holes so I strategically have a trash can to catch the water and avoid getting it on the volunteer. Though this activity is simple, students love it.

I overheard one of my IEP students talking to the Co-teacher and he said: “This is actually pretty fun!”

Explanation of the Observations

Hole 1

When the tape is pulled past the first hole you should observe that little to no water comes out of the bottle depending on how full it is. The more full it is the less water will come out.

Why? When you fill the bottle and close the cap, the top of the bottle becomes closed off from the atmosphere. When you remove the tape past the first hole, some water may flow out and decrease the pressure of the air that remains in the bottle. Once the pressure is decreased enough (usually only a few small drops of water) the water is held in because the pressure difference from the air inside of the bottle is less that outside of the bottle.

Hole 2

When the tape is pulled past the second hole, the water will flow out of the second hole. If you observe closely you will notice air is flowing into the first hole allowing the pressure inside of the bottle to increase and water to flow out of the second hole.

Hole 3

When the tape is pulled past all three holes, the air still flows into the first hole (top) allowing water to flow out of both the second and third hole.  The water in the third hole will stream farther than the second hole due to the increase pressure from the additional water.

Try it out. Comment below on how it goes!