Energy and Momentum

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Objective

Students learn that energy and momentum make objects or people move faster or slower by testing the speed of marbles on ramps.

Big Idea

Students learn that objects need more energy to move faster.

Introduction

10 minutes

Students are asked to sit on the meeting place rug to begin a new lesson on energy and momentum.

When students are all set and ready to listen, we review what we learned about the definition of energy. Energy is: the ability to do work. Energy is needed to make an object or a person move.

I explain to students that when you use force to make an object move, you are also using energy.  The more energy you use, the faster an object can go. When an object or person uses more energy, the faster that object or person can go.

I tell students that, "we are going to race marbles down two different ramps to see how fast they go".

I show the students the ramps and the marbles as everything is already set up for the experiment.

Before we begin, I ask students to go to their seats where their science journals are waiting for them. I pass out a page that we will glue in our journals that we will record our predictions on before we test the marbles. 

I have a page under the document camera so that I can show students where and what to write.  There are sentence starters on sentence strips in the pocket chart to help students who may need that guidance. Modeling is an important practice to help students meet our expectations for them. Using sentence starters helps them to talk and eventually write like a scientist. 

I explain to students that we will make a prediction about whether the marble will roll down the ramp that is taller or shorter. Students will then write their prediction down on the form in their science journals.

Experiment - Whole Class

10 minutes

When students have all completed their predictions, I have them close their journals and come sit in a half circle around the ramps that I have set up.

There are two pieces of a store bought marble run. Both are the same length. I used the same amount of pieces for both. I also use the piece that will catch the marble at the bottom. This marble run toy was purchased at a local big box store. You can also purchase it here.

I have several hardbound books that we use to prop up the ramps at different heights. One will be propped higher and the other lower.

I also have a long wooden block on hand so that we can make sure that each ramp is ending at the same distance. 

I explain to students that it is important that our ramps are the same length and that they end at the same distance to have an experiment that is concise. Scientist do this with their experiments as well.

I have two students come up to be helpers to hold and let go of the marbles when I say, "Go".  These two students will do a couple of practice runs in order to make sure they understand the directions.

When they have practiced a couple of times, we begin the experiment. The students watch carefully as the marbles are let go on the ramps. We keep a chart on chart paper of which marble gets to the bottom the fastest. We do 10 different runs to assure that we've collected sufficient data.

By conducting the experiment as a class this models for students how to properly plan and carry out an investigation Practice #3. Eventually, I want students to conduct their own investigations that include making a prediction and collecting data. 

Closing

10 minutes

After the class completes 10 different runs of the marbles, I ask students to get up and go back to their seats.

I have them open their science journals and compare the results to our predictions.

On the form, they will circle yes or no for whether their prediction was correct or not.

I then ask students some questions and we have a class discussion about energy and momentum.

Questions:

1. Why do you think the marble that rolls down the tallest ramp always wins?

2. What do you think would happen if we made both of the ramps the same height?

3. What do you think would happen if we made one even lower and one even higher than we had them?

The reason for the questions are to get the students thinking critically about the experiment and making predictions in their heads.

The ramps and marbles will then be part of our free choice activities so students can engage their natural curiosity further explore these concepts.