Density Lab

Density Lab

Objective:

1. learn the meaning of density
2. use the scientific method

Materials:

large plastic tub or aquarium, water, 1 pint carton of whole milk. 1 pint carton of skim milk, 1 pint carton of cream

TEKS:

7.1B 7.2 A thru E 7.3 A thru F

Teacher Directions:

1. Discuss density with the students. One example that is helpful is two snowballs the same size. One snowball has been tightly packed with several handfuls of snow. The other snowball is loosely packed with one one handful of snow. The tightly packed snowball's snow flakes are closer together than that of the snowball that is loosely packed.

2. Give the students the lab page.

3. Ask the students to guess what they think will happen when the cartons of milk are placed in the water. This is their hypothesis. It should begin with "I think that..". It does not have to be correct as many real scientist's hypothesis are incorrect. That is why we don't have a cure for cancer. Much can be learned from being wrong.

4. Do the experiment.
Procedure:
1. Fill the tub or aquarium almost to the top.
2. Place the pints of milk in the water.
3. Observe the levels at which the cartons float. The cream should float at or near the top of the water. The whole milk will float deeper in the water, and the skim milk should float the lowest of the three cartons.

5. Have the students write what happens to each carton in the Data section.

6. Brainstorm as a class why the cartons float at different levels. Remember when brainstorming that all answers are acceptable.

7. After brainstorming discuss (analyze) which answers are better science answers. Get the students to eliminate some and examine the science behind the best answers.

Write comparisons and contrasts on the form. Some suggested questions are:
*If you place a quarter, a CD, and a rubber duck in water what will happen? Why?
* What is the shiny liquid that forms at the top of the bowl of stew?
*Where did it come from?

8. Have each student answer the question in the Identify the Problem.
Do all cartons of milk float the same? Their answers are their conclusions based on what they learned.

Density Lab Form

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