3rd Grade Science, Unit 1 Changes in Motion
“What is gravity and what does it do?”
GLCE
P.FM.E.2 Gravity – Earth pulls down on all objects with a force called gravity. With very few exceptions, objects fall to the ground no matter where the object is on the Earth.
P.FM.03.22 Identify the force that pulls objects towards the Earth.
S.IP.03.11 Make purposeful observations of motion of objects in terms of direction.
Background
1. Gravity is the force that pulls objects towards the Earth.
2. The term gravity is very abstract. Third grade students do not need to define the term gravity. They need only to observe that dropped or thrown objects eventually fall to the ground. Some exceptions are helium and hot air balloons, or objects rising in water. Third graders may be aware of the exceptions but do not need to understand the science behind it.
3. Gravity is the attraction between all matter; it is the force that pulls objects toward each other. The larger the object, the greater the force. Because of the Earth’s size, the pull of gravity is very apparent.
4. The downward force of gravity is called weight. Weight is the measure of the pull, or force, of gravity on an object.
5. Weight is measured using a scale, whereas mass is measured using a balance.
6. The emphasis of this expectation is that gravity is the force that pulls objects to the Earth. Weight is the measure of the pull of gravity.
7. Students describe objects as having more or less pull by the Earth and more or less weight.
8. A common misconception is that only large objects have gravitational force.
Vocabulary
Gravity
Weight
Materials
2 identical small balls
a piece of copy paper
a rock
“What is gravity and what does it do?” student worksheet
pencil
Procedure
1. Hold arms straight out at sides with one ball in each hand
2. Predict what will happen when the balls are let go at the same time.
3. Let go of the balls at the same time.
4. Discuss and record what happened.
5. Hold arms straight out at sides with paper wadded into a ball in one hand and a rock in the other.
6. Predict what will happen when the paper ball and rock are let go at the same time.
7. Let go of both items at the same time.
8. Discuss and record what happened.
Lesson taken from http://www.cape.k12.mo.us/blanchard/hicks/News%20Pages/Force%20pdf%20files/Gravity.pdf
Extensions
· Complete a KWL Chart about gravity
· Video clip(s)-gravity
www.discoveryeduction.com (need subscription)
www.brainpop.com (need subscription)
· Worksheet(s)-gravity
www.edhelper.com (need subscription to access some
worksheets)
· Read book(s) about gravity
· Complete ‘Falling Dominoes’ lab
o Objects dropped from equal heights fall to earth in equal time, regardless of weight and size, ignoring air resistance
· Further Questioning: ‘What would Earth be like if gravity were gone?’
Name ______
3rd Grade Science, Unit 1 Changes in Motion
“What is gravity and what does it do?”
1. Predict what will happen when the balls are dropped:
2. Record what did happen when the balls dropped:
______
3. Predict what will happen when the paper and rock are dropped:
______
4. Record what did happen when the paper and rock were dropped:
______
5. Define gravity:
Lesson taken from http://www.cape.k12.mo.us/blanchard/hicks/News%20Pages/Force%20pdf%20files/Gravity.pdf