Here's the picture!7th Grade Life Science Curriculum
Lesson 2: Scientific Thinking
Objectives:
After completing the lesson, students will be able to:
· Demonstrate the difference between an observation and an inference
· Write good procedures for completing a task
Key Questions:
· What is an observation? Inference?
· How is an observation different from an inference?
· How do you write an accurate procedure?
Overview:
Day 1: Students write procedures for making a peanut butter and jelly sandwich
Day 2: Students will use posters, cartoons, and pennies to make observations and inferences.
Day 3: Students will look at makings at an archeology site and make observations and inferences.
Day 4: Students will test their ability to distinguish the difference between an observation and inference by observing a candle and cartoons.
Time Required: 4+ class periods
Materials:
Peanut Butter, Jelly, Bread, Plate, Knife
Interesting Posters or Cartoons
Pennies
Archeology Mystery Overhead
Banana, Almond Sliver, Plate, Matches, Goggles
Procedure:
1. Introduce the need for writing procedures when doing experiments.
2. Ask students to write a detailed, step-by-step procedure for making a PB & J sandwich for someone who has never made one before.
3. Then have students take turns reading the directions as you try to follow them. Deliberately make mistakes by being naive (try to stick knife in jar before opening it, spread jam on the crusts, put entire jar of jelly on the bread while it’s still in the bag...).
4. After the routine, emphasize the importance of details and something that can be easily followed by a person without any background info.
1. Explain the difference between an observation and an inference. An observation is information collected through the five senses. An inference is an interpretation or explanation of an observation.
2. Show a poster with people or a cartoon on the overhead. Ask students to write a list of observations and inferences. Provide examples and discuss responses.
3. Penny Observation – Give each student a penny.
4. Ask them to make three columns on their paper. Allow students two minutes to write down as many observations as possible about a their penny. Then give them some time to share in groups of three or four the observations they made. Any observation that is new is written in the second column.
5. Then bring the class back together and ask for their observations one at a time. Write the observations on the board or overhead. Ask students to write any new observations not made by their group in the third column.
6. Different students will notice different things about their pennies and not all pennies are exactly the same. Use this opportunity to explain how different students and groups will make different observations and why it is important for scientists to share their ideas with others.
1. This assignment is intended to be done on an overhead projector. Copy the set of foot prints onto an overhead transparency. It shows two sets of footprints, one small, one big in three areas on a sheet of paper labeled A,B, and C. The first area shows the two approaching each other. The second show the steps mixed in a circle and the third show the bigger one moving away.
2. Ask students imagine the class as a group of explores traveling through unmapped jungles of Africa. As they reach a clearing, they spot a series of markings on a large slate of rock no one has ever seen before.
3. Slowly reveal one section at a time on an overhead. For each section, have students write 3 observations and 3 inferences. Pause to allow time to write and discuss answers at each step. Correct any mistakes made by students.
4. After the entire page is revealed, ask students to make an inference about the entire picture. Common answers are (a predator eating a prey, line of ants meeting, parent picking up a kid)
1. In secret, make a "candle" out of a straight section of a banana and put an almond sliver at the top at the wick. Because of the oils in the almond, it will light with a match and burn it for about 20 seconds. A banana prepared ahead of time on a plate ahead of time works nicely.
2. Prepare the students for a quiz and ask them to write down as many observations as possible without talking. Emphasize that only OBSERVATIONS are to be written down, not inferences. Any inferences written will cause a failing grade. Then SLOWLY pull out the candle, pull out matches, put on goggles, light the match, light the “candle”, and blow it out. Purposely pause at each step to allow students to write. Then for the last step, making sure everyone is watching, bite off the top part of the candle and chew. Usually this elicits a reaction from the class. By this time, most students have written down candle in at least one of their observations. You can then tell them that by writing candle any where on their paper other than the title means that they made an inference. Allow the students a chance to correct their mistakes.
3. On the other side of the paper, you can give a real quiz (true/false) by stating observations and inferences about the series of cartoons. The page of cartoons can be copied on to a transparency and projected from an overhead projector. For example, statements for the first picture could include “the person has something behind him” (observation) and “the man is pulling a heavy box” (inference).
Homework:
DAY 1: Write a procedure for brushing your teeth.
DAY 2: Write 10 observations and 10 inferences about the school.
DAY 3: Using both your observations and your inferences, write a story about what led to the markings.
OUSD Science Content Standards (State of California Science Content Standards):
References:
Prentice Hall: Science Explorer Focus on Life Science
Think Like a Scientist p. 758-759, p. 376, unit 2 resources
Archeology Mystery
Observation vs. Inference Quiz
Why is mitochondria important for the cell? After this activity, you will have a better idea!
Procedure:
| TRIAL # | 1 | 2 | 3 | 4 | 5 |
| # of Hand Presses | | | | | |
cell membrane differences activity:
Making Your Own Indicator Solution:
NaHCO3 -> Na+ + HCO3
HCO3- + H+ <-> H2CO3<->H2O+CO2
PHOTOSYNTHESIS
6CO2 + 6H2O +
