mm Graph Paper

4.A.1 Collect data at different scales to answer scientific questions about the components found in blood.

See the key ideas listed on the previous page.

Take note of any students who seem confused or unsure about how to use the microscope, and be sure to check in with them first during the Investigate Blood with a Microscope lab on day 2. Also take note of any students who struggled to draw or describe specific differences they could see with the microscope versus without it or using different objectives. These students may need more practice and support with focusing the microscope before or during the lab on day 2. Consider rearranging groups who share microscopes for the lab on day 2 if you can pair more confident microscope users with those who are less confident.

Suggested prompt

Sample student response

What did you notice about what you could (or couldn’t) see with and without the microscope?

(Accept all responses.)

How did changing the objectives change what you could see? Why?

• The higher the objective’s number, the closer we were zoomed in.
• We know the total magnification changes with the different objective lenses. We could see much more detail at the higher numbers.

When you were looking at that millimeter graph paper at each of those magnifications, how much of it could you see?

• At 40x/low magnification, we could see about 4 or 5 mm.
• At 100x/medium magnification, we could see only 1 or 2 mm.
• At 400x/high magnification, we could see less than ½ mm.

The amount of space you can see at one time is called your “field of view.” How does the field of view change at different magnifications?

• At higher magnifications, there’s a smaller field of view--we can see less space but in more detail.
• At lower magnifications, there’s a larger field of view--we can see more space but in less detail.
• Summarize this discussion by saying something like, We can use this information to help us understand the scale of what we’re seeing when we’re looking at blood (or anything else) with the microscope.
• See sample poster on the right.

Ask, What else did you figure out about using the microscopes that we’ll want to keep in mind while we’re observing blood (or other things)?

Sample student responses might include:

The knob(s) on the side(s) of the microscope adjust the focus--they raise and lower the place you’re looking at. (Teacher may choose to name the stage.)

• You could see better by adjusting the light on the microscope. There is a dial you can turn to make the light brighter or dimmer.
• You really do have to move slowly, or even back and forth a little bit, to find the clearest view.

SUPPORTING STUDENTS IN MAKING CONNECTIONS IN ELA

Some students might confuse “microscope” with “telescope.” If you have a moment, ask students to try to infer what the “tele” in “telescope” means based on what they know about what microscopes and telescopes do (from Greek: “tele” means “far” or “at a distance”). You might also ask students to list other words that use “micro” and consider what part of their meaning is “small.”

Conclude today’s work. Display slide M. Say something like, Today we explored with the microscope because we were thinking using this tool might help us figure out more about what is in the blood. How could using the microscope help us figure out more about what is in the blood?

Sample student responses:

• We can see really close up what is in the blood.
• Since the blood is found in all the different parts of the foot that was injured, maybe we can see what is in the blood so we can figure out what it does in each of these parts.
• Say, Let’s plan to use this tool to look closely at some samples of blood next class and see what we can find out.

HOME LEARNING OPPORTUNITY

If your class did not read How do eyeglasses help people see better? from Lesson 6 of the One-way Mirror Unit, you might want them to read it as home learning now.